MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: OllieVRS on June 15, 2022, 01:12:55 am

Title: Dyno Day Disappointment
Post by: OllieVRS on June 15, 2022, 01:12:55 am
Went to the dyno before work to see how my car was performing stock with just a cold air intake, Rev G DV and on Irish 95 octane (raised roughly to 98/99 octane with octane booster).

(https://i.postimg.cc/6p1qmTQ7/IMG-20220614-133407.jpg) (https://postimg.cc/DSL7WvLF)


Got to say I'm pretty bummed to have gotten 184hp. I expecting 195+, especially considering the cold air intake is supposed to add a few horses even without a map.

But my engine's compression was 145psi last time I checked 6000km ago, so that may be part of the reason for such a disappointing result.

The guy doing the dyno run also pointed out the weird bumpiness in the graph, and suggested something may be wrong with the spark plug gapping  :stupid:. I changed out the spark plugs 1000km ago with some NGK BKR7EIXs so I dunno.

I'm planning on returning in a month or so to get remapped on 95 octane without any booster, hopefully that won't be the final nail in the coffin for my engine  :grin:
Title: Re: Dyno Day Dissapointment
Post by: Clarkj93 on June 15, 2022, 06:49:42 am
Any reason for sticking to 95 and not 99?

A really good service could raise the numbers. Mine had a creation motorsport intake, miltek cat back, pre cat delete followed by a good service (fuel filter, r8 coils, oil etc.) And an inlet valve and fuel injector cleaning and made 220bhp before mapping. May have been less before the inlet cleaning mind. Your torque curve also seems to drop before mine did when it was stock, mine dropped at about 5500 rpm. It does look quite bumpy though as said already.
Title: Re: Dyno Day Dissapointment
Post by: rich83 on June 15, 2022, 08:03:37 am
Odd. Torque numbers are about right.  :thinking:
Title: Re: Dyno Day Dissapointment
Post by: OllieVRS on June 15, 2022, 10:55:55 am
Any reason for sticking to 95 and not 99?

I'm in the Republic of Ireland, unfortunately all we get is 95 octane.

My engine is too abused from having low oil pressure and not enough maintenance to justify spending money on having the injectors cleaned. But it's also not worth spending €2k+ on replacing it with another used engine if I'm only losing 16hp.

The fuel filter was changed 20k miles ago. I also got a P0441 'Tank venting system, incorrect flow, Permanent' code that's somehow not throwing up a CEL, but I don't think that should affect the engine's horsepower. Oil and filter was changed less than 1k miles ago. No misfire codes or anything like that.

Odd. Torque numbers are about right.  :thinking:

Yeah that is pretty weird, I thought they were directly linked/correlated? Since 280NM is factory spec, shouldn't the horsepower figure be in or around 200hp too? Could the dyno be off a bit?
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 15, 2022, 11:15:44 am
after my experience with so called octane boosters im gonna guess without it added you will see better numbers slightly,
these cars are supposed to run on superunleaded, if you run it on 98 your performance will be around 197bhp i bet..
Title: Re: Dyno Day Disappointment
Post by: pudding on June 15, 2022, 01:00:45 pm
HP implies measured at the wheels, otherwise it should be BHP if a crank figure.

Did Mr Dyno man state if his readings are wheel or crank power?

I wish all dynos would just quote standard kilowatts  :stupid:

Bumpiness in the line is likely detonation if he applied smoothing to the graph.
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 17, 2022, 11:20:58 am
after my experience with so called octane boosters im gonna guess without it added you will see better numbers slightly,
these cars are supposed to run on superunleaded, if you run it on 98 your performance will be around 197bhp i bet..

Well I'm going to be going back in a month for a remap after running the car on a tank or two of just 95. When he dynos the car before the map we'll see if you're correct and if the booster's useless.

I'm kind of hoping you're right though, that it'll still be 180hp+ on 95. Otherwise if the octane booster actually works it should read ~170hp on pure 95, which would put me on par with a diesel vRS  :scared:
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 17, 2022, 12:16:22 pm
it would be interesting if you could fill up with 99ron fuel from newry for your next dyno, dont know how close you are to them but it would give you an idea of how close you are to quoted bhp using the recommended fuel, generally 1 extra octane generates an extra 5bhp i found,  so if you got 180 bhp on 95, add 15bhp from 3 extra ron bringing it to the recommended 98 ron that would give you 195bhp which is only 2 bhp down from quoted when new figures which for a 16 year old car would be brill..
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 17, 2022, 12:40:31 pm
it would be interesting if you could fill up with 99ron fuel from newry for your next dyno, dont know how close you are to them but it would give you an idea of how close you are to quoted bhp using the recommended fuel, generally 1 extra octane generates an extra 5bhp i found,  so if you got 180 bhp on 95, add 15bhp from 3 extra ron bringing it to the recommended 98 ron that would give you 195bhp which is only 2 bhp down from quoted when new figures which for a 16 year old car would be brill..

I'm in Dublin but after I get it mapped and I'm in the north I'll definitely fill up there, then come back for another dyno. Although some people on the forums do say that it being '99 octane' is a load of bollocks, since it's the only pump in Northern Ireland (afaik) selling above 97 octane.
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 17, 2022, 09:43:22 pm
are you sure theres no where in dublin that sells super?  seems odd, 
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 17, 2022, 10:11:18 pm
are you sure theres no where in dublin that sells super?  seems odd,

I'm 100% positive nowhere in the entirety of the Republic of Ireland sells above 95 octane. There is premium stuff of course, but even that still says 95 octane on it. I've done hours of googling, all with the same conclusion that it's simply not imported to the republic, and not imported because of environmental policies/green party/not enough demand etc.

There's been a few occasions in the past where people have found 97 octane on pumps here, but it has always been an error and fixed quickly by the petrol station.
Title: Re: Dyno Day Disappointment
Post by: RBS on June 17, 2022, 10:21:48 pm
Weird!?! :thinking:
Title: Re: Dyno Day Disappointment
Post by: RBS on June 17, 2022, 10:24:06 pm
Was it a hot day when you went on the dyno?? Heatsoak is an enemy…
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 17, 2022, 11:06:25 pm
Was it a hot day when you went on the dyno?? Heatsoak is an enemy…
   catch yourself on...lol    this is in ireland    wish some of that nice english weather would blow over here..
Title: Re: Dyno Day Disappointment
Post by: ROH ECHT on June 18, 2022, 02:46:21 am
NGK BKR7EIX are a 5k Ohm restricted plug. You really should consider going back to the 1k Ohm plug (NGK 1675 PFR7S8EG) w/gaps at 0.8 mm, and allow more voltage to pass through the plug when stock as yours is. At stock there's no need to restrict the power for the arc it can generate. Because your combustion situation is not likely to disturb its arc.

You may consider, if just seeking higher power numbers, try a lower visc oil to 0W20...if using 5W30. Or 5W30...if using 5W40. That always makes more power....but you might want to change it back after the dyno day.

Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 18, 2022, 03:18:05 pm
NGK BKR7EIX are a 5k Ohm restricted plug. You really should consider going back to the 1k Ohm plug (NGK 1675 PFR7S8EG) w/gaps at 0.8 mm, and allow more voltage to pass through the plug when stock as yours is. At stock there's no need to restrict the power for the arc it can generate. Because your combustion situation is not likely to disturb its arc.

You may consider, if just seeking higher power numbers, try a lower visc oil to 0W20...if using 5W30. Or 5W30...if using 5W40. That always makes more power....but you might want to change it back after the dyno day.

I'm not really too familiar with the technicalities of the gapping but I just bought what is recommended by other members on this forum.  But the car's getting remapped soon, so it hopefully there is a big difference in the the remapped power and it can take advantage of the spark plugs I bought (if I understand what you're saying correctly).

There's no way that I'm going back to 5W-30 though. My oil pressure on hot idle on 5W-30 was 15.3psi where the normal range is 14.5-17.4, so I upped the oil to 5W-40 to raise it to 16.6 which I deemed acceptable.

Also even on 5W-40 I'm using about 0.8L/1000km, so going back to 5W-30 would make that even worse, for the sake of a couple horsepower.

But that begs the question: how much does switching to 5W-40 lower horsepower?

Nevertheless tanks for the suggestions, always appreciated  :smiley:
Title: Re: Dyno Day Disappointment
Post by: ROH ECHT on June 18, 2022, 04:28:52 pm
I'm not really too familiar with the technicalities of the gapping but I just bought what is recommended by other members on this forum.  But the car's getting remapped soon, so it hopefully there is a big difference in the the remapped power and it can take advantage of the spark plugs I bought (if I understand what you're saying correctly).
I'm not a proponent of switching plugs without the need for it. I used a 1k Ohm plug (and OE stock coils) even when I added the K04 & tune and it was then over 320bhp. That first tune I ran for six years and its boost was 22psi ±1psi. I didn't need a 5k Ohm plug until I switched its tune to one which boosted more than 25 psi and made more than 340bhp.

There's no way that I'm going back to 5W-30 though. My oil pressure on hot idle on 5W-30 was 15.3psi where the normal range is 14.5-17.4, so I upped the oil to 5W-40 to raise it to 16.6 which I deemed acceptable.

Also even on 5W-40 I'm using about 0.8L/1000km, so going back to 5W-30 would make that even worse, for the sake of a couple horsepower.

But that begs the question: how much does switching to 5W-40 lower horsepower?

Nevertheless tanks for the suggestions, always appreciated  :smiley:

It is in fact minimal...30 to 40 or 40 to 30, at 200bhp is near ±2 bhp.

Generally the oil pressure on a healthy engine isn't affected more than near 11% (average I found based on what others report seeing with a 10 viscosity change)...so at 15.3psi, going 30 to 40 would typically raise it to 16.9psi (15.3*1.11=16.9).

Oil does evaporate, but not at a rate of 0.8L/1000 km. It likely needs work before adding HP to it. When mine got to 1L/800 miles...I had to rebuild the head (new valve stem guides and seals), new rings, one piston (for a ring stuck in its piston-groove) and went ahead and replaced the rod bearings.
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 18, 2022, 05:40:58 pm
I'm not really too familiar with the technicalities of the gapping but I just bought what is recommended by other members on this forum.  But the car's getting remapped soon, so it hopefully there is a big difference in the the remapped power and it can take advantage of the spark plugs I bought (if I understand what you're saying correctly).
I'm not a proponent of switching plugs without the need for it. I used a 1k Ohm plug (and OE stock coils) even when I added the K04 & tune and it was then over 320bhp. That first tune I ran for six years and its boost was 22psi ±1psi. I didn't need a 5k Ohm plug until I switched its tune to one which boosted more than 25 psi and made more than 340bhp.

There's no way that I'm going back to 5W-30 though. My oil pressure on hot idle on 5W-30 was 15.3psi where the normal range is 14.5-17.4, so I upped the oil to 5W-40 to raise it to 16.6 which I deemed acceptable.

Also even on 5W-40 I'm using about 0.8L/1000km, so going back to 5W-30 would make that even worse, for the sake of a couple horsepower.

But that begs the question: how much does switching to 5W-40 lower horsepower?

Nevertheless tanks for the suggestions, always appreciated  :smiley:

It is in fact minimal...30 to 40 or 40 to 30, at 200bhp is near ±2 bhp.

Generally the oil pressure on a healthy engine isn't affected more than near 11% (average I found based on what others report seeing with a 10 viscosity change)...so at 15.3psi, going 30 to 40 would typically raise it to 16.9psi (15.3*1.11=16.9).

Oil does evaporate, but not at a rate of 0.8L/1000 km. It likely needs work before adding HP to it. When mine got to 1L/800 miles...I had to rebuild the head (new valve stem guides and seals), new rings, one piston (for a ring stuck in its piston-groove) and went ahead and replaced the rod bearings.
with regard to spark plugs, im running a stage 1+  around 255bhp,  i have the ngk7iex, would you suggest going back to stock plugs tuners seem to recommend going down a heat range for every 50 bhp increase?
Title: Re: Dyno Day Disappointment
Post by: ROH ECHT on June 18, 2022, 07:51:19 pm
...with regard to spark plugs, im running a stage 1+  around 255bhp,  i have the ngk7iex, would you suggest going back to stock plugs?
I do suggest doing so. For the reason the 5k Ohm BKR7EIX further restricts voltage and current. And can force a need to reduce plug gaps. The original 1k Ohm PFR7S8EG will allow more arc to span a greater gap which burns fuel more efficiently. So long as a violent (added boost and heat) combustion isn't disturbing the arc. So yeah, I never suggest following a general statement made by tuners suggesting their general rule. I personally would only go from 1k Ohm to 5k Ohm when you've upgraded coils to a known higher voltage coil...or if an increase in boost and heat begins disrupting its arcing. You will feel this when boost and heat affects the arc in that you'll feel a stumble when approaching upper revs at full throttle. Even then you may first try simply reducing the gap of a 1k Ohm plug to 0.65mm to 0.7mm, from the standard 0.8mm gap for ours.
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 18, 2022, 10:49:17 pm
...with regard to spark plugs, im running a stage 1+  around 255bhp,  i have the ngk7iex, would you suggest going back to stock plugs?
I do suggest doing so. For the reason the 5k Ohm BKR7EIX further restricts voltage and current. And can force a need to reduce plug gaps. The original 1k Ohm PFR7S8EG will allow more arc to span a greater gap which burns fuel more efficiently. So long as a violent (added boost and heat) combustion isn't disturbing the arc. So yeah, I never suggest following a general statement made by tuners suggesting their general rule. I personally would only go from 1k Ohm to 5k Ohm when you've upgraded coils to a known higher voltage coil...or if an increase in boost and heat begins disrupting its arcing. You will feel this when boost and heat affects the arc in that you'll feel a stumble when approaching upper revs at full throttle. Even then you may first try simply reducing the gap of a 1k Ohm plug to 0.65mm to 0.7mm, from the standard 0.8mm gap for ours.
is it possible to gap the iridiums if your very careful or is that a no go,
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 19, 2022, 12:43:54 am
Thanks for all the replies guys!

It is in fact minimal...30 to 40 or 40 to 30, at 200bhp is near ±2 bhp.

Generally the oil pressure on a healthy engine isn't affected more than near 11% (average I found based on what others report seeing with a 10 viscosity change)...so at 15.3psi, going 30 to 40 would typically raise it to 16.9psi (15.3*1.11=16.9).

Oil does evaporate, but not at a rate of 0.8L/1000 km. It likely needs work before adding HP to it. When mine got to 1L/800 miles...I had to rebuild the head (new valve stem guides and seals), new rings, one piston (for a ring stuck in its piston-groove) and went ahead and replaced the rod bearings.

EDIT: I miscalculated, the oil consumption is actually 0.4L/1000km

My engine is definitely not healthy. It has suffered low oil pressure twice during my ownership and at least once in its previous ownership, based on physical evidence on the oil pump (scratches showing that the balance shaft sprocket had come lose in the past). It has had far too long service intervals too, which I stupidly ignored while viewing the car.

The compression is 145psi, which is far worse than what @ald1717 (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=103199) said he got in his post from a few hours ago and my mileage isn't that much greater at 121k miles.

Two of the exhaust valves were found to be slightly wet with oil when the turbo was being replaced by my mechanic, but nothing drastic. I expect this to be a major cause of the oil usage, other than the piston rings. I can't say 100% it's as much as 0.8L/1000km since I live in a hilly area where it's hard to get an accurate reading, but it's my best estimate.

But I have replaced the connecting rod bearings (in situ), as they were pretty cloudy with a few scratches when I took them out. Thankfully the crankshaft looked fine, but I took a risk and didn't measure its diameter.

I am planning on running this engine till it dies, with a replacement rather than a rebuild in mind, since it's already gone through so much neglection. The rings, pistons, cylinder walls, valves etc would all have to reworked/replaced I think.

Also I would have to pay a mechanic to do the rebuild as I simply don't have the space in my house nor do I have access to a garage, and a professional rebuild would be much more than a used engine. I'm already budgeting money for this, and will only get a remap once I know I have enough money saved to replace the engine.

If I can squeeze 220hp+ out of this engine on 95 RON without it self-destructing, then I'd be delighted :grin:

...with regard to spark plugs, im running a stage 1+  around 255bhp,  i have the ngk7iex, would you suggest going back to stock plugs?
I do suggest doing so. For the reason the 5k Ohm BKR7EIX further restricts voltage and current. And can force a need to reduce plug gaps. The original 1k Ohm PFR7S8EG will allow more arc to span a greater gap which burns fuel more efficiently. So long as a violent (added boost and heat) combustion isn't disturbing the arc. So yeah, I never suggest following a general statement made by tuners suggesting their general rule. I personally would only go from 1k Ohm to 5k Ohm when you've upgraded coils to a known higher voltage coil...or if an increase in boost and heat begins disrupting its arcing. You will feel this when boost and heat affects the arc in that you'll feel a stumble when approaching upper revs at full throttle. Even then you may first try simply reducing the gap of a 1k Ohm plug to 0.65mm to 0.7mm, from the standard 0.8mm gap for ours.

Is it worth spending another €50 on getting those exact spark plugs, rather than sticking to my current ones? Would it solve the dyno bumpiness and add a few horses? Sorry if I'm throwing to many questions at ya, I just want to see my Octy performing its best without financially ruining myself in the process :smiley:
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 19, 2022, 01:09:25 am
if your stock probably worth sticking stock plugs in as i only went colder as im tuned,
Title: Re: Dyno Day Disappointment
Post by: ROH ECHT on June 19, 2022, 07:34:10 pm
 

EDIT: I miscalculated, the oil consumption is actually 0.4L/1000km

The compression is 145psi, ...

Two of the exhaust valves were found to be slightly wet with oil when the turbo was being replaced by my mechanic, but nothing drastic. I expect this to be a major cause of the oil usage, other than the piston rings.
Prior to the rebuild of mine at 120k miles, the compression I had was 191 to 195 in all four. But this is how oily/wet the combustion chambers were in mine with worn valve guides, bad valve stem seals, and stuck piston rings in #3 and #4. It is obvious that most of the oil, if not all, was due to the rings:
(https://i.postimg.cc/yY12HgLR/head-removed.png) (https://postimages.org/)


Is it worth spending another €50 on getting those exact spark plugs, rather than sticking to my current ones? Would it solve the dyno bumpiness and add a few horses?
I would and then just hang onto the BKR7EIX for when tuning possible requires them. Because even when tuned, the original 1k Ohm plugs will likely perform better with the stock coils and provide better fuel mileage.

Title: Re: Dyno Day Disappointment
Post by: pudding on June 20, 2022, 11:37:26 am
Two of the exhaust valves were found to be slightly wet with oil when the turbo was being replaced by my mechanic, but nothing drastic.

Yep, the head needs a rebuild.  Exhaust guides always the first to go on VAG engines.

Fitting a refreshed head is a quick way to restore compression and reduce oil consumption.....providing the cylinders/pistons aren't screwed.

Don't waste time or money with spark plugs, that isn't your issue.  It's just a tired engine, but hopefully just the top half.  A new engine will be 3-4000 from TPS.  I would sell the car now if I were you.  The money pit only gets deeper.  There's always something with these engines......just when you get it running how you want, the bloody injectors go down and that's another £800 + labour.  It never ends.
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 21, 2022, 04:58:15 pm
Two of the exhaust valves were found to be slightly wet with oil when the turbo was being replaced by my mechanic, but nothing drastic.

Yep, the head needs a rebuild.  Exhaust guides always the first to go on VAG engines.

Fitting a refreshed head is a quick way to restore compression and reduce oil consumption.....providing the cylinders/pistons aren't screwed.

Don't waste time or money with spark plugs, that isn't your issue.  It's just a tired engine, but hopefully just the top half.  A new engine will be 3-4000 from TPS.  I would sell the car now if I were you.  The money pit only gets deeper.  There's always something with these engines......just when you get it running how you want, the bloody injectors go down and that's another £800 + labour.  It never ends.

I've already gone through this dilemma of selling vs. keeping it and running it until it dies (and then fixing it again).

The car is worth ~€4000-€4500 at 121k miles in the current Irish car market, second lowest mileage petrol MK2 VRS I've ever seen for sale. A replacement engine with similar mileage can be bought anywhere between €1000-2500, most likely imported from the UK. I'd plan on renting an engine crane and doing the work outside my house, I estimate another €500 for the crane, extra tools, fluids and stretch bolts. I can borrow my dad's mighty Volvo V50 to transport the replacement engine if I can't get it shipped :smiley:

So that's €1500-3000 to get a decent used engine, also gives me the opportunity for an easy k04 conversion and to put on a stronger clutch.

Or I can sell it now for €4000. There are no other petrol MK2 VRSs for sale in Ireland currently, so I would have to replace it with something else of similar age & mileage.

These are my options (not to mention insurance difference which at my age for these cars would be a lot higher):
MK5 GTI - €7000
Leon Cupra - €8000
Civic Type R FN2 - €8000
Astra OPC/VXR - €7000
Megane RS225 - €7500
Focus ST - €7500 (and has annual road tax of €1250)

(I would love to get an S3 or TTS as my next car, but they are both €12000+).

As you can see the difference in value between my car and these other comparable cars is roughly the same if not more than the price of a replacement engine. Combine that with the fact that I am paying a very reasonable insurance price as Irish insurance companies class my Octavia as a family car, making it even cheaper to insure than my dad's bog standard 1.8 petrol V50.

Hopefully this is good enough justification for my financial suicide, as a petrol head I don't see any other option than to stick to what I've got. As I said before, I'll only get the remap when I've got enough money to comfortably throw in another used engine.

If anything expensive goes (e.g. the injectors, clutch or whatnot) it'll be enough justification for me to replace the engine. But until that happens I'm running this one 'till it dies.

I will be going back the Dyno in a few weeks on just 95 octane, and I think I'll get those spark plugs, if I'm able to get similar power without 100ml of the Millers VSPe PowerPlus Multishot I had in last time I'll be happy. Although I am crossing my fingers that either the octane booster didn't work or having slightly incorrect spark plugs caused the disappointing result.



Also here's a video I posted before of the valves, it's not that bad right?  :wink:

Title: Re: Dyno Day Disappointment
Post by: Irish_Mk5 on June 21, 2022, 10:22:46 pm
Where did you get it dyno’d?  There is huge variety in figures between dynos from what I’ve seen.

And I’ve heard mixed reviews about air intakes. VW put a lot of effort into designing the car, what makes people think a replacement is any better? without the proper remap an intake can reduce bhp.

And you’re correct about being limited to 95 octane unfortunately :(
It’s possible to get remapped for 95 but I don’t know if this brings any extra power
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 21, 2022, 11:41:19 pm
Where did you get it dyno’d?  There is huge variety in figures between dynos from what I’ve seen.

And I’ve heard mixed reviews about air intakes. VW put a lot of effort into designing the car, what makes people think a replacement is any better? without the proper remap an intake can reduce bhp.

And you’re correct about being limited to 95 octane unfortunately :(
It’s possible to get remapped for 95 but I don’t know if this brings any extra power

Sportchip in Ballycoolin, Dublin 15.

Remapping on 95 definitely brings extra power. Usually on Donedeal ads you'll see people selling MK5 GTIs saying 'Stage 1 250hp' or some other nonsense like that. That figure is based on a generic map on 98 octane.

The guys who actually dyno the car after getting it mapped say '238bhp' or '236bhp' in their ad, which for 95 octane sounds about correct where the remaining horsepower is lost due to not using 98 octane.

I added enough octane booster to raise the octane to an estimated 99, and that's why I'm so disappointed about the HP I got on the dyno. I need to back without octane booster and the correct spark plugs and see what it does then, hopefully not under 180hp  :scared:

If every dyno is different, it would be stupid to go to another dyno now as I won't know whether or not the octane booster and spark plugs made any difference. I'll stick to Sportchip for now.
Title: Re: Dyno Day Disappointment
Post by: ald1717 on June 22, 2022, 11:08:52 pm
Two of the exhaust valves were found to be slightly wet with oil when the turbo was being replaced by my mechanic, but nothing drastic.

Yep, the head needs a rebuild.  Exhaust guides always the first to go on VAG engines.

Fitting a refreshed head is a quick way to restore compression and reduce oil consumption.....providing the cylinders/pistons aren't screwed.

Don't waste time or money with spark plugs, that isn't your issue.  It's just a tired engine, but hopefully just the top half.  A new engine will be 3-4000 from TPS.  I would sell the car now if I were you.  The money pit only gets deeper.  There's always something with these engines......just when you get it running how you want, the bloody injectors go down and that's another £800 + labour.  It never ends.

I've already gone through this dilemma of selling vs. keeping it and running it until it dies (and then fixing it again).

The car is worth ~€4000-€4500 at 121k miles in the current Irish car market, second lowest mileage petrol MK2 VRS I've ever seen for sale. A replacement engine with similar mileage can be bought anywhere between €1000-2500, most likely imported from the UK. I'd plan on renting an engine crane and doing the work outside my house, I estimate another €500 for the crane, extra tools, fluids and stretch bolts. I can borrow my dad's mighty Volvo V50 to transport the replacement engine if I can't get it shipped :smiley:

So that's €1500-3000 to get a decent used engine, also gives me the opportunity for an easy k04 conversion and to put on a stronger clutch.

Or I can sell it now for €4000. There are no other petrol MK2 VRSs for sale in Ireland currently, so I would have to replace it with something else of similar age & mileage.

These are my options (not to mention insurance difference which at my age for these cars would be a lot higher):
MK5 GTI - €7000
Leon Cupra - €8000
Civic Type R FN2 - €8000
Astra OPC/VXR - €7000
Megane RS225 - €7500
Focus ST - €7500 (and has annual road tax of €1250)

(I would love to get an S3 or TTS as my next car, but they are both €12000+).

As you can see the difference in value between my car and these other comparable cars is roughly the same if not more than the price of a replacement engine. Combine that with the fact that I am paying a very reasonable insurance price as Irish insurance companies class my Octavia as a family car, making it even cheaper to insure than my dad's bog standard 1.8 petrol V50.

Hopefully this is good enough justification for my financial suicide, as a petrol head I don't see any other option than to stick to what I've got. As I said before, I'll only get the remap when I've got enough money to comfortably throw in another used engine.

If anything expensive goes (e.g. the injectors, clutch or whatnot) it'll be enough justification for me to replace the engine. But until that happens I'm running this one 'till it dies.

I will be going back the Dyno in a few weeks on just 95 octane, and I think I'll get those spark plugs, if I'm able to get similar power without 100ml of the Millers VSPe PowerPlus Multishot I had in last time I'll be happy. Although I am crossing my fingers that either the octane booster didn't work or having slightly incorrect spark plugs caused the disappointing result.



Also here's a video I posted before of the valves, it's not that bad right?  :wink:


let me know if your interrested in a mk5 gti as mine is going up for sale tomorrow sadly as i just purchased a 7.5R  but if i do sell it i will be very sad great cars if looked after and hard to beat for old scool handling and steering feel, thing is ive spent that much on keeping it in tip top that i will loose aroung 2-3k even if i get a fair price..
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on June 23, 2022, 01:22:06 am
let me know if your interrested in a mk5 gti as mine is going up for sale tomorrow sadly as i just purchased a 7.5R  but if i do sell it i will be very sad great cars if looked after and hard to beat for old scool handling and steering feel, thing is ive spent that much on keeping it in tip top that i will loose aroung 2-3k even if i get a fair price..

Thanks, but no thanks, I wouldn't be able to insure it until November anyways, and my current insurer wouldn't let me unfortunately.
Title: Re: Dyno Day Disappointment
Post by: OllieVRS on July 21, 2022, 07:56:06 pm
A month later and I've finally done a compression test and measured the oil consumption.

155-154psi, on a lukewarm engine after 3.5 hours of being turned off.

Oil consumption is 0.416L/1000km, but there is a small leak on the vacuum pump.

Turbo was rebuilt, spark plugs replaced, oil wasn't changed too long ago and timing belt is also pretty new.

How much risk is there in getting it remapped? I now have enough money saved to replace the engine if it comes down to that.
Title: Re: Dyno Day Disappointment
Post by: pudding on July 22, 2022, 09:17:37 am
10-14 bar is in the acceptable to good compression range, so why not.

8 bar is rebuild time, as decreed by VW.

Oil consumption is a tad high to be honest, possible piston rings if compression is at the lower end.  But you never know until you pull it all apart as it could also be poor valve seating, particularly on the exhaust valves.

I say go for it.  If you've got a contingency fund, life's too short to procrastinate.