v5/6 WRX engines (non STI) what CR?

[gazzy2000]

 Stoffa said:

sweet we maybe onto a winner with my ecu then, i'll get it sent today, sorry i was too busy yesterday

yea cheers, just when you can manage, thanx

I have also Emailed NZ EFI in CH-CH and ask the same question.

[gazzy2000]

Wicked!! i have solid evidence that the v5/6 GC is 8:1 CR and the GF is 9:1

will post again soon, still reading...

[gazzy2000]

K, looks like all JDM WRX non STI GF8's (wagons - non STI) are 9:1 Compression Ratio, dunno about NZ new.

I would have to say this is pretty conclusive, yea? So i am after a GF8 v5/6 ECU non sti ;D

From the web site http://english.auto.vl.ru/catalog/

Click the pics to see bigger versions.

99 GC8 (sedan - non STi) 8:1 Compression Ratio

99 GF8 (Wagon - non STi) 9:1 Compression Ratio

99 STI Wagon GF8 8:1 Compression Ratio

[newsuba]

NZ new v5/6 WRX sedan & wagon ran 8.0:1

[gazzy2000]

 newsuba said:

NZ new v5/6 WRX sedan & wagon ran 8.0:1

interesting stuff, good to know!

[gazzy2000]

BTW - it was todgat that put me on to that site, thanks man!

[Stoffa]

i just put the ecu in a courier bag at the post shop so you should see it tomorrow

[gazzy2000]

 Stoffa said:

i just put the ecu in a courier bag at the post shop so you should see it tomorrow

sweet thanks! so was that out of a wagon?

[Stoffa]

yep, nz new, auto, v5 wagon

[gazzy2000]

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

[pl0x]

 gazzy2000 said:

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

hmmm changes thoughts on a few things then...

where did the everyone thinking it was the CR causing the DET ever come from?

[gazzy2000]

 pl0x']

[quote name='gazzy2000 said:

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

/quote]

hmmm changes thoughts on a few things then...

where did the everyone thinking it was the CR causing the DET ever come from?

i thought it mainly spanned from the findings with my BH TT to ST conversion...

- i tried a stock STI v5/6 ECU firstly, never ran right, always in safe mode i.e. MAJOR det

- after major troublshooting i spoke to a tuner around that time he said my engine is 9:1 & STI ECU is 8:1

- it was suspected that the STI ECU ran far too advanced timing for the 9:1 CR engine causing det

- i brought a Link ECU (off a tuner)

- i told him all about the CRs etc, he said being that the link is tuned for a 8:1 engine (his wifes) i wud definately have to pull some timing

- i fitted the link, it deted bad still, untill we took 10 degrees timing out then it was mint

- Kevin at PBMS said yea 10 degrees +/- when playing with 8:1 & 9:1 compression ratio engines sounds about right

Begs the question if that car that the link i brought came out of had stock BH heads or STI heads? my car drives pretty bloody good though

[Stoffa]

 pl0x']

[quote name='gazzy2000 said:

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

/quote]

hmmm changes thoughts on a few things then...

where did the everyone thinking it was the CR causing the DET ever come from?

Revision D Legacy's running 9.0:1 CR, thats where

[gazzy2000]

i actually think the fact that where i had an ECU tuned for 8:1 CR (all beit a Link ECU) was detonating on the 9:1 CR engine, then pulling the timing 10 degrees 100% fixed the det problem is rather definitive, and proves that the engine to ECU CR missmatch is the main casue of the Det problem.. dont you think?

The Rev D Det problem IMO, is slightly different in that they are tuned for 100 Octane and have 9:1 compression ratio, they function fine until we in NZ start running 95-98 octane which causes the det, but yea pull the timing and the rev D 9:1 engine runs fine.

So yea that guy i spoke to today prolly has a fair point about cam profiles etc, and it may well be in the BH ST conversion that the det prob is made worse when using a ECU like the STI ECU on a non STI engine...

But bugga me... wheres the scientific proof LOL... we need a dyno day, 2-3 cars including BH5, Rev D, WRX v5/6, WRX v5/6 STI & a heap of ECUs to swap in and out (sedans, hatchs, STI & WRX)... not ganna happen!

I am just trying to make the right decision on what OEM ECU to use.

[Stoffa]

I got my hands in a B4 short block today that I'm about to strip down, if I can find some v5 sti pistons I can compare them.

[gazzy2000]

 Stoffa said:

I got my hands in a B4 short block today that I'm about to strip down, if I can find some v5 sti pistons I can compare them.

^^ i have an old v4 STI piston if thats any good?

The chap Ewan i got my link off has offered me a 9:1 ECU out of a JDM wagon, so once i get that i will trial (carefully) that NZ new one and the JDM one.

[Stoffa]

nah version 4 is no good, they run a different pin height

[Jord]

Sweet good stuff gaz! Please get back to us with your findings.. If the JDM GF8 ecu works there may be a few more 3rd gen ST conversions going on!

[Stoffa]

how did you get on?

I'm picking up some v5 sti pistons today so should be able to compare

[mattapo]

 gazzy2000 said:

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

balls, the profiling of the gtb cams is very very close if not the same as the sti

[gazzy2000]

 mattapo']

[quote name='gazzy2000 said:

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

/quote]

balls, the profiling of the gtb cams is very very close if not the same as the sti

i wud need scientific data before i believed anyone or anything on this topic anymore lol,

I am just going to try the ECUs that i have, listen for Det (with my listening device), pick the best one based on performance and lack of det, then get a AFR test done, then i am done

[gazzy2000]

 Stoffa said:

how did you get on?

I'm picking up some v5 sti pistons today so should be able to compare

hey, havnt done anything as yet, waiting for another ECU to turn up before i start

Will let you know

cheers

[pl0x]

Mind you, when i rang the people who re-built my engine (Mitchel Motorsport?)

Asking what compression they built it to as i wanted to convert to single turbo etc they said a similar thing - Well sort of, saying the cams and sti ecu is to advanced for my engine or something.

Basically just trying to get rid of me cause they didn't calculate the compression.

[gazzy2000]

 pl0x said:

Mind you, when i rang the people who re-built my engine (Mitchel Motorsport?)

Asking what compression they built it to as i wanted to convert to single turbo etc they said a similar thing - Well sort of, saying the cams and sti ecu is to advanced for my engine or something.

Basically just trying to get rid of me cause they didn't calculate the compression.

yea right, who knows if its only a v5/6 STI and a BH thing..

coz v3/4 all seem to be sweet i.e. say a 97 GTB engine with the single turbo conv done runs a v3/4 STI ECU no worries.

[nt_a_foz]

 gazzy2000']

[quote name='gazzy2000 said:

Got a phone call back from a chap at PF automotive (subaru specialists in Tauranga) to chat about CRs etc

Told him my what i have leanrt on this thread and about the det issues is had during my TT to ST conversion due to compression ratios etc

He reckons the Det on my BH TT to ST conversion was prolly more-so due to the cam profile being completely wrong for the tune of the STI ECU i first used.

Meaning he reckons the CR is much of a muchness and he wud be more concerned with using a STI ECU on a non STI engine that dosnet have the right heads/ports/cams

So its almost down to... use a non STI computer on a non STI engine and you'll be sweet (regardless of CR) ???

Interesting!

/quote]

balls, the profiling of the gtb cams is very very close if not the same as the sti

i wud need scientific data before i believed anyone or anything on this topic anymore lol,

I am just going to try the ECUs that i have, listen for Det (with my listening device), pick the best one based on performance and lack of det, then get a AFR test done, then i am done

If you were talking to Dave from PF Automotivbe hes the owner and very well respected in the Rally Circles from what i know. Kooms mates rally car from CHCH gets looked after by him even though hes in Tauranga. Had subarus for years and when i went to the workshop last year had some REAALLYYY cool cars in there lol