I would say that a hybrid is perfect for your sort of power goals.

That CAT looks fubar!

On the lambda thing - I thought a lambda below 1.0 indicated a rich mixture?

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GT4DC Events Co-ordinator
1996 ST205 UK

ah really well i need more air somehow then, on my dyno print out they have put leaning out in high revs.

If it is leaning out then that is very bad! I would suspect your ECU.

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GT4DC Events Co-ordinator
1996 ST205 UK

no ive changed the ecu since then, but i havnt had the dyno re done since then though. it could be a lambda probe maybe? im also leaning towards a duff cat like mine giving a rubbish reading to the second lamba probe. It only leans off in the last 500-600 rpm.

The ST205 does not have a 2nd lambda probe. The one at the bottom of the CAT is a temperature sensor.

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GT4DC Events Co-ordinator
1996 ST205 UK

what is your afr mate ?

my stock ecu runs 10.5:1 under WOT to the redline

I don't have a clue the afr levels aren't on the dyno.

bit of a bugger that, usually they print you afr along with the boost you are running, usually a fair indicator of somethings to see if somethings wrong

Hi and welcome to the club. It was good to meet you briefly at Japfest.

Lambda equates to AFR - AFR = Lambda x Stoich (14.7 for petrol) The sensor measures lambda, and the AFR is calculated from this for the fuel type. Higher number = weak, lower number = rich.

Turbo engines normally run stoich (14.7AFR or lambda 1) for idle and cruising as this gives the best ecconomy and preserves the cat. On boost, the mixture needs to be richer to keep things cool. Generally, 12 AFR is considered the safe upper limit. Standard ECU is normally about 10.5, aftermarket ones tend to be mapped at about 11.5 - 12 depending on the safety margin vs power requirement.

Lambda 0.85 equates to 12.5:1 AFR which is rather a dangerous figure to be running on boost. This could just be an incorrect mapping with the ECU or it could indicate a fuel system problem such as blocked filter, old/weak pump or it could be the ECU not switching the fump to full power. The latter can be checked with a voltmeter between FP and E1 on the diagnostic connector. With engine idling it's normally about 9V, if you give the throttle a good blip it should go up to 12V-13V.
YOU SHOULD SORT THIS ISSUE OUT BEFORE RUNNING FULL BOOST.
If you can post your dyno printouts with lambda may be helpful.

Re. turbo, many/most hybrids will lose a lot of drivability. Going up hills in 5th becomes a thing of the past. Others on this club have experience with the TT one and can comment further.

I agree with Don about not restricting the exhaust, this is very much a sticking plaster fix. More restriction = more hot exhaust gas left in the cylinder to mix with the incoming mixture and negate the advantage of a good intercooler. IMO either use a hybrid that doesn't suffer boost creep or go for an external wastegate. Maybe consider a Garett or Borg Warner turbo. Andycaca made nearly 350BHP at 1 bar on an otherwise standard engine at the last RR day I attended with (from memory) a 3076 Garett and motec ECU.

Re. MOT's, according to my current tester, anything after 1992 requires a CAT test, however if it fails they are then allowed to do a non cat test for anything up to 1995 as long as exact emission figures aren't in the database. (They aren't for an import).

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If at first you don't suck seed, try drier grain.

Okay need to point out that the rolling road was not done by me but the previous owner so I have never seen any afr print out unfourtuently. Since the rolling road I have changed the ecu and I hav not been on the rolling road since so I have no idea if the problem still exists.

I have not changed the fuel filter so that will be my first port of call, I'll test the fuel pump to as that seems simple enough. Can a faulty lambda produce these results?

I'm probably gonna avoid a hybrid and stick with a stock turbo, I'm not aiming for high figures approx 320, I'm happy to be on level par with scoobies and evos. The cat is very much a weekend car as I cycle to work but I drive to Brighton (about 75 miles) every weekend so I want some drivability.

You say you are not aiming for high power but 320bhp is still 33% more power than stock and at the limit for stock internals. Using a standard CT20b ST205 turbo you will have two issues:
1. The CT20b turbo ceramic shaft is not as strong as a steel hybrid and;
2. Running high boost levels using an OEM CT20b the compressor will be feeding extremely hot air which the standard water to air intercooler can't cope with. The net result is an increased risk of detonation and possible ringland failure.
As a workaround and as a cheaper, simpler alternative to fitting a front mount intercooler I used water injection to keep the plenum temps down to ~35degC. Without this, the temps are north of 60degC.
If you still want 320bhp I'd definitely recommend a hybrid turbo.

_________________
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

I am planning on a front mount at some point soon probably around august when I have some time off. This water cooling idea is that easy to fit, I've not really heard of it before.

Forgive me if I'm wrong but don't wrc models have some sort of water injection?

Cat looks melted on my small screen. Coupled with a previous did turbo it might point to anti-lag use or just high afpr readings and hence high egts

As nibbles said you need to get a rr printpout of afr as a matter of some urgency. Even club type shootouts usually include afr if you can find anything local going on - generally itro 30 snots rather than much more for a dedicated run

I did look at my fuel filter today and it looks like its not been done in a while as it has Japanese writing all over it so got one on order. I'll change the turbo and exhaust once I done that I'll get on the rolling road.

Annoyingly the only 4wd dyno near me is the one where all the guys on the gt4oc are today but I wasn't going to do a power run with the state the turbo is in today.

some of us on the OC are ok.

we had a good day at Surrey Rolling Road yesterday, a couple of ST205 running over 400bhp.

Matador came and put his Audi RS5 on the rollers as well, 409bhp.

My ST205 is poorly so I cheated and ran 526.9bhp in the car I took along instead. They would not let me have the trophy for the Best Power Run as I wan not in my ST205.