MaeckyMY98

Hello!

Where you have the Limiter for your 2.5 Engine with the normal European Specs GT Heads?

How much boost are you running on the standart USDM2.5 Internals?

reg

Markus

Tim W

iTrader: (1)

Markus, if your using standard European market heads then stick with the same rev limit as the standard 2.0 litre...because it is the heads that are the limiting factor.

On the subject of max boost on standard EJ257 internals it seems that 1.4 bar is the safest bet (mapped correctly), much over that and there seems to be problems with the ringland on the hypereutectic cast pistons cracking, and/or the head gaskets leaking...although that maybe a temperature cylcing issue...

MaeckyMY98

Hello

fine so 7000rpm is ok.

How much power will be there on 1.4bar?

Tim W

iTrader: (1)

That entirely depends on your turbo, mapper, other mods etc...although enough to break the gearbox is perhaps a good way of putting it

MaeckyMY98

Hello!

Here are the mods i have:

USDM 2.5
TD05/06
Header
3 inch turboback
Link ECU
FMIC
740cc Injectors
MRT Inletpipe

how much power should be there?
How long to hold the 1,4bar boost? up to redline??

R19KET

RPM limit isn't just about the heads, you also have to consider the rod bolts. The higher the RPM, the more stress is put on them, and eventually they can stretch, and cause baring problems, or worst case, snap.

On the standard rods/bolts, personally, I would have a 7000rpm limit, for safety.

I can never understand why people apply a "max" boost limit to an engine, unless it also applies to a specific turbo too.

1.4 on a TD04, or 1.4bar on a GT35R ?

I would expect 1.4bar on a TD05/6 to be ok through the low/mid range, but a bit too much for the turbo at higher rpm.

The best person to advise on this combo' is John Banks, who has run the same set up. Or check out his thread in "Projects".

Mark.

MaeckyMY98

Hello!

Im sure that the 1.4 on the TD05/06 is too much to hold it up to redline.
I think i set the 1.4 till 5500 and then slowly back to 1.1 at 7000.

john banks

Try doing power measurements at 1.4 flat, 1.2 flat, 1.0 flat. Overlay them, then you will see the ideal boost profile to run. I would think that you would get about 400 BHP out of it on 98 RON with headers, 3" exhaust, good intercooling etc. I got 434 BHP and 395 lbft running 1.4 bar mid, 1.2 bar at the top with 90% Optimax, 10% methanol, on rollers that read a decat MY00 at about 220 BHP.

I tapered off to 1.2 at the top with 20G and EJ257, running some extra octane. 1.1 is probably more sensible on Optimax.

The iON is happier running 1.2 to the top, can run 1.3, 1.4 and it is quite difficult to avoid detonation on Optimax.

Take a guide from the duty cycles required to hold the boost, boost creep if excessive can cloud this. A flat duty cycle on a weak actuator should mean you aren't overdoing it too much, but it is only a guide.

My 20G crept to 1.1 from memory at about 6000 RPM but then dipped down again.

Re rev limit, I've run mine to 7500 RPM. What they don't like is wild timing with 1.7 bar of boost on a methanol fuelled top speed frenzy

Some would argue that 1.7 bar isn't sensible on pump fuel full stop, even on a built motor.

Quirt Crawford posted in his forums that he thought 8000 RPM was OK for a stock EJ257, rod failures seem rare. Some report that the balance leaves something to be desired compared with a "proper" EJ207 STi motor. Certainly they feel smoother revving their nuts off. The EJ257 pistons are brittle if you allow detonation or chase timing, which these engines don't take and don't like. I found I couldn't be quite as hashy with it as I got away with multiple times on the EJ20.

My current plans on this engine are to try a larger turbo running 1.4 bar but breathing freely at the top, will be interesting to see what power it makes and how it stands up to it.

MaeckyMY98

Do youn think the European GT Heads can stand 7500?

John wich ECU are you using?

911

John, did you deliberately drop the boost from 1.4 to 1.2/1 as revs rise? (on the 20g)
I'm just removing the sports cat off my 2 litre/20g as the Apexi could only hold 1.2 @ 3400, 1.4@ 3800 and started dipping boost at 5000/5500 finishing at 1.2 at 7800.
AndyF thought this was due to the flow restriction of the cat fitted.
Full 3'' decat back-on tonight with a tweek via the Commander to allow 1.4 from low 3000 to 7800 red line.
With the cat on the power/torque delivery was very smooth.

Graham.

Andy.F

Graham, John is referring to the 2.5 engines ideal boost profile on the 20G. (he has also ran the same turbo on the 2.0 though)
A turbo supplying a 2.5 at 1.2 bar at 6000rpm is flowing the same air as a 2.0 at 1.75bar at the same rpm (assuming similar VE)

Andy

john banks

MaeckyMY98, I'm using the OEM ECU, reflashed so far. I'm changing to an Apexi for the GT30R setup if Andy and I can get the MAF well mannered, or failing that I can get the MAF simulator box (with 10 rather than 8 bit DAC and faster update for simulated MAF output, code is part done, hardware needs just a few wiring swaps if that) working well with good transients - Andy got it near, but it needs road car miles to setup, in other words the transients are a pig to map, and it would take a week or so driving to work to do it I think P20SPD has lent me his P&P MoTeC M800 to play with, impressive as it is, the throttle will have to be adjusted to stop it stalling (which I'll do when it stops snowing and I feel better), and it really needs other sensors to work correctly, but it has huge potential, but also massive costs.

I found the 20G seems to peak power about 10% lower revs on the 2.5/STi heads/big bore manifold than the 2.0/UK heads/OEM manifold. I had to run very very silly boost on my 2.0 setup to get 406 BHP because I didn't have the manifold. I think the power you can get is similar, but needs less boost than the OEM manifold. When I tried similar tricks on the 2.5 to try to dyno queen as near to 500 BHP as I could, it said **** you Banksie. You need to treat it like a nice lady, not a common prostitute like you can get away with on the 2.0 it seems That 2.0 that I ran nearly 2 bar through is still running (not at that boost).

911

Bit off thread, but I will need to ring you Andy to go through the Commander setting for the decat that is now bolted on.
Thanks for the tech answers, always something to learn...

911

P20SPD

iTrader: (1)

My standard uk heads were fine at 7500 on my 2.5 with the GT30R running 1.6bar through them.

Deep Singh

Why an Apexi John?

john banks

Apexi, because you can live map it, with or without a laptop, adjust a few things you can't on the OEM ECU, it is a lot cheaper than other standalones and has the manners of the OEM ECU. It has the right level of complexity to do a nice job on a lot of cars. Only downside is getting the MAF working properly with a big turbo that can send funny airflow patterns back over it.

MaeckyMY98

So i you put 1,6 thru your GT30R and standard UKHeads at 7500 i should be fine if i put 1,4 trhu my european standard Heads (mildly ported) till 7500 on my TD05/06 setup? Anyone getting scared from my ideas?

Andy.F

As long as you don't blow up that nice turbo Markus

I think your first plan is best
Trying to hold 1.4 at 7000 on a 2.5 with a 20G will probably result in less power than 1.1-1.2 bar

Andy

MaeckyMY98

Andy i dont whant the same nightmare again so i will take much care for the Turbo! ;-))

So i will Dial in 1,4bar up to 5500 and the move down to 1,1bar at 7000 i think this will be no Problem at all and there should be a nice Power curve.

Andy what you think how much Power will be there with my mods if its well mapped?

Wich AFR you would take for safety?

I think i need a longer 5th Gear cause the Gearbox i have right now has a topspeed in 5th gear at 7000 of 233km/h!

cu

Markus

Andy.F

Depends on the fuel octane/ambient temperature/driving style ?

MaeckyMY98

Fuel will be Optimax with 100 Octane and Driving Style will be Fast Road Use ;-))

Engine is Running now fine on Idle, today in the afternone i go out for a drive to see what it does while cruising if this is fine i will apply a little boost

Anyone have some more tips wich i had to know to tune the Link?

Good night or good morning

Markus

harbering1

My car 1.4 bar till 5500 Rpm and 1.1 a 1.2 bar till 7000 Rpm

my98 2.5 sti block td06/05 550 injectors FMIC link ecu

the injectors where @ 96 % between 3500 Rpm and 5000 Rpm

From 5000 till 7000 it was 92 % injector duty

fuel pres was set @ 3.5 bar with the !@#@#$$% FSE

The td06/05 on a 2.5 is midrange monster

MaeckyMY98

harbering1

Can you mail me your LINK map to have a look at it?

i have set the Fuel Press to 3,4 on my 740cc´s but idle is not very fine so i think i had to take out a little bit and try again

anyone with a suggestion about the power it will make
or anyone wich have a car with same setup and who was on a dyno?