Pavlo

António,

You have my sympathies, though fortunately not from personal experience.

I beleive the engine you have is very similar indeed to Christian's, certainly in terms of the block and internals, and the company that supplied them! He was getting 360hp at 1 bar boost with his setup, again on a Motec ECU.

I find it difficult to totally comprehend how the SR50 could be so very different to how it's advertised. You could forgiven for thinking that APS have never even run a 500hp engine with the turbo.

What I find harder to believe is that sort of power has been seen on EJ20 engines in the uk with just a hybrid VF turbo, using less boost.

Could there be a way that you're losing boost somewhere, but measuring is with the motec and boost gauge close to the turbo? That could account for some of the loss, but I imagine the boost is being read on the manifold.

Bananas in the exhaust? Or more feasable, someone's left a rag or other object in an exhaaut component?

Paul


[Edited by Pavlo - 12/11/2002 8:24:18 PM]

nom

Could also be a banana (or small animal) in the inlet (well, between the turbo & cylinder). Where's the boost measured? Plenum? And any idea of chare temperature (intercooler or interheater)?
I'm just throwing wild accusations about here; brain is definately at idle

Hmm, reading a little more carefully this time was the garrett taken out & the APS stuck in - no other changes/(mechanical) work but there's the drop in power?
In which case it's unlikely any stray animals have got in anywhere.
It certainly doesn't even remotely match up with the blurb or "compressor maps" that they have on their website.

[Edited by nom - 12/11/2002 8:59:08 PM]

António Correia Jr

Hi,

I've purchased an APS SR50 Turbo for my 2,5l engine project.
I was expecting 450-500hp at the flywheel using a motec, but I had no success yet. Best result was 360hp at 1.6 bar.
With the same mapping a Garret 450hp turbo produced 400hp at 1.3 bar.
I've been researching and I've read some comments about this turbo, namely, that its exhaust side is rather small for the 500hp figures APS claims it to be ready.
Before I present my case to APS, I'd like to know if anyone has experience with this turbo series.
Any other comments?

Thanks in advance,

António Correia Jr.

Pavlo

The inlet is rather small too. As pointed out to me by an "expert witness" so to speak.

All that air through a std size turbo inlet?

Any dyno plots? Torque at various rpm?

any more info gratefully received

paul

R19KET

António,

I suggest that you compare the intake diameter, and exhaust housings of both turbo's.

I would also suggest comparing the back pressure in the up pipe. You just need to weld a small boss on the up pipe, so that you can attach a boost gauge.

Which Garrett is it.

Mark.

hypoluxa

360bhp with a 2.5L and running 1.6bar on a supposed 500bhp turbo is might disappointing to say the least...

From the reports I've heard, I don't think anyone has made anywhere near 500bhp with an SR50.?

As Mark suggests measure the turbine inlet pressure - I think you will be surprised.

Trout...

Wasn't there a post a while back where APS 'claimed' to have three cars running in Oz - Sti 7s with standard 2.0l internals - running 450bhp with the SR40 turbo. If that is true then 360bhp at 1.6bar is a little disappointing to say the least. (My 2.0l car pushes out close to this at 1.3bar and only 2.0l )

On that thread APS were very keen to demonstrate the capability of their turbos - although they had no graphs to back it up at the time.

Mind if you, if you took your car to the States I am sure it would be pushing out at least 500bhp with this set up

Trout

R19KET

I suspect that there is something else going on here, other than the ability of the SR50 to produce more than 360bhp @ 1.6bar.

I have my own opinions about it producing the 550bhp APS rate it at, but it should certainly do better than 360bhp @ 1.6bar.

I would also check the wastegate actuator on the SR50, it may well be blowing open under boost.

You really need to give a little more info, such as,

1) at what RPM was the Garrett producing 400bhp @ 1.3bar.

2) at what RPM was the APS turbo producing 360bhp @ 1.6bar

You say it was with the same mapping, and this could also be an issue. How did the fuelling compare, at a given rpm, at a given boost ?

Mark.

António Correia Jr

Hi again,

Thanks for your comments.

Unfortunately I’ve no way to measure the turbo’s intake or exhaust.
Let me explain where I’ve gotten myself into:

About a year ago I started researching for a project: a 500hp Impreza.
I’ve spent several days surfing the net for the best options for my project.
APS enjoyed great reputation and the SR50 series turbos were in development. I immediately thought that this could be the way to go. I bought the cold air intake and the FMIC and immediately placed an order for the SR50 turbo.

I then came across with an Australia-based firm whose name I won’t be disclosing at this point. They prepared me a closed deck EJ25 engine with all the goodies (forged pistons, stronger conrods, gas-flowed heads, etc.)

Because any engine is useless if it’s not correctly tuned, I asked this firm to handle the job using the parts I had bought from APS.
They are using a Motec E48 that is more than suited for the work. They enjoy an extensive experience in Imprezas and they have designed a twin-turbo version with 600hp.

So, after almost a year, I was expecting to receive my long-awaited engine. I would be more than glad with 400+ hp, but 360???? As someone pointed out, I could have obtained this sort of figure without resorting to an EJ25…

It’s obvious that something is wrong, but who’s to blame?

I’m still searching for answers. For now, I’m starting to see that many people are complaining from the figures presented by APS regarding their turbo’s capabilities.

On the other hand, there is a project from Cobb Tuning – Conebasher – that is said to be delivering 420hp at the wheels, with a similar setup to mine.
I’ve contacted the owner of the car and I hope he can shed some light on this.
Incidentally, Cobb Tuning has ceased to represent APS in the US. Of course there is a statement saying that the reasons have nothing to do with any of the companies…

I'm waiting for a more detailed report from the tuner and I'll post here any more info I can get.

Until then, I'll be greateful for any more comments you might have.

R19KET

It's always going to be very difficult, when the work is being carried out so far from home.

Firstly, be very careful when comparing power figure from the US, with the rest of the world, they rarely equate to each other.

We would still need the type of information I mentioned, to get a better idea.

Whilst I'm not a fan of some of the APS products, I don't believe the SR50 is THAT bad either. IMO, something else is going on.

Ask the guy (Robin ?) to email you a copy of the Motec map, and a datalog using both turbo's. If you then send it to me, or whoever, so it can be looked at, and see if it indicates where the problem may be.

I assume that the guy who built/mapped it has an opinion, what is it ? and I'd still like to know what Garrett turbo was used.

Mark.

Pavlo

I'm afraid small animals seems like a good explaination so far!

I just don't see how mapping could be that far out?

More seriously, I would get them to put the garret back on and test, or strip and inspect. You never know, but something could have gone amiss at the end of the first garret run (assuming it was first) to screw up the next set of results.

Other things that spring to mind:

Cam timing slipped sometime
Rings broke
Intermittant ignition fault from faulty wiring
MAP sensor has bust (unlikely)
Exhaust blowing (would hear it though)
Run out of oil (you never know!)

Data like exhaust back pressure and inlet temperature would be good, you would expect to see big changes to make such a difference in power, given the APS is supposedly a higher power turbo to start with.

Paul

António Correia Jr

Thanks again for your comments.

I'm still waiting for a detailed report from the tuner.

I know that the APS had the first run and was then replaced by the Garrett (I recall this garret is part of a kit developed locally - don't know the model name or if it has some mods or not, but I'll find out).

R19KET, you've guessed right (regarding the firm).
I still have faith in the firm that is handling this package since any query I submit to the web is returning me good information on their services.

As the engine was built from scratch and is being tuned on the dyno bench, I can only think of two valid causes for this issue:

a) as good as the tuner may be, he is not adapting to the sr50;
b) the sr50 is indeed being over-rated by APS and a non-aggressive mapping will not produce satisfactory results.

Hope to have some raw data soon to share with you.

Trout...

Pavlo,

I quote..."What I find harder to believe is that sort of power has been seen on EJ20 engines in the uk with just a hybrid VF turbo, using less boost."

There are a number of cars in the UK that have done between 350 and 360 (on rolling roads to be fair) with VF hybrids (or in one case a Power Enterprise turbo) running between 1.25 and 1.35 bar.

Or have I misunderstood your statement?

Trout

R19KET

António,

If the engine has been run on an "engine dyno" there should be printouts available with lots of info.

Mark.

Pavlo

Trout,

I mean that cars here with EJ20 engines, using VF hybrids, are making 360hp with less than 1.6bar of boost.

Which would suggest that however shy of 500hp the APS turbo is, it should still compare favourably/similarly with an IHI hybrid.

Which I think is just what you have said?!

paul

Adam M

Pavlo,

the APS turbo is a IHI hybrid.

It just has a custom compressor cover over an IHI core.

Adam M

ooops.

moray is of the belief (and I think he may be right) that the exhaust housing is custom to allow it to be fitted in standard place but accept a garrett core. He also seems to think it has a garrett cover.

This is actually ringing bells for me now, but I wonder if it is a garrett cover why they retained the poxy inlet diameter. Perhaps to allow it to mate to standard pipework and sod the fact that the turbo is being strangled?

sphazell

Found out some very interesting figures
Chassis dyno
APS SR50 (525hp) turbo max power at wheels 220kw
AVO 400hp turbo on the same car and dyno on the same day. Guess what max power 220kw.

On engine dyno APS SR50 (525hp) 360hp max at 1.5bar (What the F***) and hp fell off after that. Figures are genuine.
On same Engine dyno 440hp GT25 Garret produced 430hp

This is no suprise to alot of people in Aussie