Hi all

1st off a quick list of engine mods to help with my query...
CT26 stage 2 with ported wastegate
HKS silent power back box with 3'aussie pipes through to downpipe
Blitz SUS induction
HKS dumpvalve
Blitz sbc boost controller
AEM air/fuel ratio gauge

Ive been reading old posts on what would be the maximum boost i could run with the above parts , would i be right in having 0.9 bar for regular driving and when i want to go some 1.2 bar?
Also what is the standard compression ratio?

Ive also noticed that boost creep seems to be an issue particually in cold weather conditions and also over fuelling seems to be an issue aswell.

I havent actually driven my car since fitting the above parts as im waiting on getting an MOT so i cant account for these issues on my car specifically, its just the threads ive been reading, they all seem to have similar modifications to mine.
Is it a generic problem with similar modified 4's or just depend on each individual car?
If its generic then what sort of measures can i take to prevent the above from happening?

I only want to know so i can get off to a good start with mine and have it running as sweet and safe as possible as im sure you can all appreciate!

Many thanks
Matt

The limiting factor in your spec sheet is the lack of charge cooling. This can be achieved by using a front mount intercooler or water injection using something like the ERL kit. Not everybody is a fan of water injection but it is a very cost effective way of pulling charge temps down by around 25 deg C to ~30 deg C and significantly reducing the chance of detonation ocurring.

0.9bar would be quite safe and 1.2bar for limited bursts. If you fit an FMIC or WI then you could run 1.2bar fairly safely at any time.

Regarding overfueling, this is partly down to the way Toyota designed the engine to run under boost to keep everything cool and avoid lean AFR's which could result in melted pistons. This is made worse by removing the catalytic converter and running a downpipe. So long as its not extreme enough to result in bore wash its not a problem. I originally ran a Dastek Unichip piggyback to pull some of the fuel off the OEM map but it was on maximum and still the engine ran rich on full boost. Short of fitting a fully programmable ECU there's not much more you can do.

If you set up your boost controller in cold weather then it won't be so prone to overboosting in the dense cold air.

Standard CR is 8.5:1 on the ST205

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Thanks for the info Don very helpful indeed!

Where should i be looking to get hold of a water injection kit and how much roughly do they cost?

As regards to the boost ill run it at 0.9 bar all the time and maybe set it to 1.1 bar for the odd short burst to keep things safe, also where i live tempratures aren't really getting much above 5 degrees at the moment anyway so should be ideal for setting up the boost, i should have the AFR gauge fitted in by the wk end to so that'll give me a good idea aswell.

One option for water injection is http://www.aquamist.co.uk There are prices there too. There are other similar suppliers but I had an earlier verion of this kit and it works fine.

_________________
Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp