This car is kind of unique in not a good way. The compression before I started to tune it was only 100psi across. Its not from ring wear, because the engine is completely fresh and new. We tuned it anyways upon owners request.

Its supposed to be a 10.5:1 piston and with R2 cams with a mivec head it would most likely be around 170psi or so. Well this was only 100psi.

Then to top that off we got E60 fuel only to work with. However anyone who has played with flex fuel and various ethanol blends, knows that 60% is as powerful as 85% almost. Even 40% ethanol is very powerful. The more ethanol, the better cooling affect (liquid FMIC you could say).

The turbos rated for 550hp, and thats basically what it did.

The engine is being torn back down now to see why the compression was so low from day one before any tuning, so I will re-tune it once its back together again with proper compression. I am not charging to retune it, since its the least I can do to someone that has to go through all that labor twice. I haven't told him that yet though. He will know after he reads this thread.

Mods are:
Evo 8 converted to Evo 9
2.1L 10.5:1 de-stroker
Ported Evo 9 Mivec head
GSC R2 cams
Sparktech non Cdi cop
Qm 8 leg twin disk clutch
Precision 1200cc injectors
Fore innovations inline fuel filter
Walbro 465lph modded fuel pump with rewire
Fuelab adjustable FPR
Oem ported and ceramic coated exhaust manifold
Map EF3 Turbo
3" downpipe and exhaust
3.5" FMIC /w upper/lower piping
3" SD intake + Big K&N Filter
Tial Q BOV
Hallman pro
Grimmspeed 3 port
Tephra v7 Speed density /w hybrid boost

Graph displaying two different boost levels:

 

That sucks... A few questions, was this self built or by a shop?

Could the head to 4g64 sealing that some people sometimes have cause this intense compression decrease, or would there be signs of such, į.e oil consumption etc...?

What I'm trying to ask is, could there be another reason other than the usual piston ring failure that would cause a brand new build to fail miserably?

 

Its not ring related I wouldn't think. Each cylinder has exactly 100psi across. I dont think it increased with a cap full of oil either.

I never seen or heard of the 8/9 head on 4g64 block cause any issues. If it was HG related or something of that sort, it would be most likely not consistent across all 4.

He built it himself. He will figure it out, hes pretty smart and knowledgeable.

 

What rod and piston combo did he use? I'm just wondering if he was sold the wrong pistons for his 2.1 build.

 

Was the vehicle wired for the mivec or was this disabled?

 

Super good numbers for 100PSI compression! Car looks super clean also! Sux to rip down a motor right after building it. That is prob not very fun.

 

That I am not sure.

It was wired for mivec and enabled.

Ya it does for sure suck. I would not be to happy, but at the same time i would be motivated to want to know what the issue was and more curious then ever.

 

Any update on what caused the low compression?

 

That is low. Mine is the opposite. I have 10.5:1 pistons and have 230+ PSI across all cylinders. Let us know what was going on. Hopefully he tried a different compression tester and a leak down test before tearing it apart.

 

Did the car owner check cam timing? A miss timed cam causing more overlap would decrease dynamic compression.

 

Is it smoking? was the compression test done correctly?

Power looks great Tom! Have a similar build build that just went kaboom. Dropped a valve into a cylinder on this build compression was 9:1 it was a 2.1L also with EF3, map long runner and R2.

 

100psi is really low if thats correct. had a car in here once that had 90psi. by definition I would say it wouldnt start. I did get it started by installing a huge battery and jump starting with as many amps I could get to the starter. starter needed to turn twice its normal crank speed before it started.

 

It runs and drives fine. I don't think he tore it down yet. Mivec engines are lower compression just naturally when doing compression tests.

I do think it should be atleast 70psi more then it is though with a 10.5:1 compression with the cams & mivec.

If anyones interested in knowing what hes doing with it now i can send him an email and ask. He doesn't use evom I don't think.

 

Tell him to use a different compression tester. Results can vary.

100psi on all 4 and make 550hp doesn't make much sense at all.

 

I bet he used a 2.4 piston which would be a lot less compression if used on a stock 2.0 crank. I would do a leak down and compression test again to see if it has issues or if it was just a misused set of pistons.