chet123

iTrader: (7)

Me too, I think it's surprised us all. Although leaving the mapping session the car did and does drive very well which is important to me, but I'm also very sure that it would've driven even better with it's expect figures.

dynamix

iTrader: (3)

Was indeed a strange one. Boost is strong, timing is good compared to normal engine and fueling should be all co-inciding to produce the power. No gains to be had from optimising the cam timing either as that was tried too and made a 1bhp gain. Maf flow was high and no unusual fuel tendencies such as running rich indicating boost leak post turbo.

Difficult to pinpoint why it is not showing the figures on the dyno as the bum dyno says otherwise...

Exhaust is 2.5 inch which may be a restriction but it is an expensive process for the OP of trial and error to change parts to find where the loss is occurring.

ScoobyDoo69

iTrader: (17)

Wouldn't have thought a 2.5" exhaust would be restrictive though, given that most suggest 3" is overkill at this level?

dynamix

iTrader: (3)

agreed but changed a backbox on a car with a 2.5 system last month and made 20bhp more on the dyno on a straight back to back. Was quite a shock.

ScoobyDoo69

iTrader: (17)

Just a back box? Wow that's something!

What system is on Chet's car?

Tidgy

different cars get different results, fueling is good, boost is good, timing is good (from what was said) so its just the car won't give any more. I know a classic uk that wouldn't go over 245bhp no mater what they did to the map and that expected around 260bhp, some cars just dont make the expected power.

if its made 4bhp more then its at 322bhp (unless i missed a figure somewhere), 330bhp is an average figure for what they make, your only 8 off that, so in the ball park so just enjoy.

Not worth going from a 35 to a 34, if you change go for an sc36 or sc40

o and bum dyno is notoriously inaccurate lol

harvey

iTrader: (48)

It is not necessarily a change in diameter but a change in design to a much less restrictive back box. I have been involved with 2 litre cars with 3" open neck D/P and 2.5" system producing well over 400 bhp with no apparent restriction on the exhaust. One was a TD05 20G Hybrid of my own and the other an SC46.
Secondly, take the car, once warmed up, to some speed on a level straight road, get it into neutral and let it free wheel to a stop. You are looking for drag from the centre diff particularrly, front or rear diff or even brakes. Wiout using the brakes, do they feel hot?

Chet, give me a ring please.

dynamix

iTrader: (3)

Checked the brakes on the dyno Harvey and no heat in them, no excessive heat in tyres either. Obviously couldn't check drag on diffs on dyno dynamics though.

MartynJ

Yes you can, you just need to know how

harvey

iTrader: (48)

I have made an offer to Chet he can hardly refuse but travelling may be an issue for him.

ScoobyDoo69

iTrader: (17)

Sounds exciting!

chet123

iTrader: (7)

As promised new charts posted

Flywheel
http://www.flickr.com/photos/7683311...7631435352384/

At Wheels
http://www.flickr.com/photos/7683311...7631435352384/

Air Fuel Ratio
http://www.flickr.com/photos/7683311...7631435352384/

Geomentary setting - so we know the wheels are not wanting to drive in all sorts of directions
http://www.flickr.com/photos/7683311...n/photostream/

chet123

iTrader: (7)

Bugeye_scoob, Curious to know how you got on with your recent setup?

L.J.F

iTrader: (31)

I would suggest having a compression test carried out as a next port of call.....

MrNoisy

iTrader: (28)

You've got the power at wheels and at flywheel back to front again mate!

In regards to mine, the car initially only ran 355/330, but we found a couple of minor issues which needed to be resolved.
A subsequent test run on the dyno to confirm what the problem was showed the car should hopefully be running about 370bhp or a little more, so if Simon can extract that I'll be happy

Even so, the car pulls like a train in every gear now with the 20g, and overtaking is SO much more fun

Chet - mate if Harvey has made you a friendly offer of help I would strongly recommend you take him up on it.
He is a TOP bloke and really knows his stuff.

Thanks,

Giles

dynamix

iTrader: (3)

The compression is even from the sound of the car starting up although may be down on all four evenly I suppose...

Bob Rawle

What were the gm/sec peaking at ? Its not too much down and could simply be a very minor air bleed somewhere. Headers and up pipe change won't get you any greater headline power as such since the std items were not a restriction in the first place at this level but they will improve response.

Do you have an after market intake pipe fitted or a std one?

Std air box is good for nearly 400 bhp with a K & N so thats no restriction.

Just because a car makes boost does not mean its flowing enough air to make power, you can have pressure in a completely blocked pipe which means nothing goes anywhere. Try the garden hose trick. You get best flow from a hose with least pressure, if you restrict the end to increase hose pressure flow drops. Odd analogy but the principle is the same.

But its possible the engine is just a bit different in terms of cam timing, if thats off line then power will suffer (bank to bank).

Duncan did you actually push it to the det line to see where that was? Ignition numbers can look normal but in fact be misleading as I am sure you know.

A few thoughts.

cheers

bob

dynamix

iTrader: (3)

Bob it was peaking at around 275gm/s so the air was flowing through the engine.

Yes I took to the det line as far as ignition is concerned to try and get the most from it and also played with cam timing as you would expect. Ignition was good and estimates from air flow would suggest higher power output should have been seen.

Tried lower boost too to see whether they netted an increase in power but no joy.

It wasn't a low reading dyno day as some can be as had two great results on the two previous cars - just this wasn't wanting to show the power. It isn't a lot out but it is at the lower end of the power expectations for the mods done.

chet123

iTrader: (7)

Thank you all, especially the renowned engine builders/tuners for sharing your experiences. Its nice to see a passionate bunch of guys, who each have different opinions but are working together to achieve the same goal (my goal ).

I've pointed out in posts #1 & #28 which mods I have had fitted since I've owned the car.

Clearly I am not gaining the power figures which I should be expecting with these list of mods.

As mentioned in my first post I am one for maximising what I have and not one for replacing unecessary parts when the standard internals would see me good for around 400.

- A 2.5" turbo back exhaust system is good for 380
- A Standard K&N Panel filter upgrade is good for 400
- A 255 Walbro fuel is a safe recommendation for fueling
- A 3 port boost solenoid allows a mapper better control of the boost
- Harvey Smith (Wrapped) Slip Jointed Up-pipe (numerous benefits, as you will all know)
- Harvey Smith (Wrapped) OEM Ported Headers (as above)
- Standard Pink STI Injectors good for 380
- VF35 good for around 340 (without meth etc)
- At most maximum boost on this turbo and internals @1.5
- TMIC is good for 380
- Standard 6 Speed STI gearbox good for 400+
- Dyno Mapped (OS)

Its so strange to read several WRX's with similiar mods seeing 330 which is up from 225 standard (imports can vary) where an sti type uk standard is 265.

I understand what the average performance is for similiar modded cars but having read claims of what potential gains can be had by upgrading certain parts and to have not achieved that is a little dissappointing. I appreciate its not always about chasing numbers, if it was I would go down the route of a 2.1 forged, SC46, FMIC, CAIK blah blah blah - thats not my goal here. For me its about making use of what I have and to try and establish reasons behind potential restrictions/faults/problems.

Subaru's! funny old things!

On the up side I have a set of NKGPF7B's and rear Whiteline 22mm ARB to go on soon. Am also going to get a compression test done to be sure. The engine has covered 63k miles

chet123

iTrader: (7)

Harvey, thank you for your kind offer. Personally, time as well as distance is an issue here but I will consider it.

L.J.F

iTrader: (31)

I agree that with the mods you have the power should be at Least 330-340 and think further investigation is needed starting with the comp test who is the nearest respected Subaru specialist near you?

rickya

iTrader: (18)

I'd consider a 3 inch bell mouth decat downpipe and what and how old is clutch?

harvey

iTrader: (48)

On a recent car we could not fathom out the problem but soon got to grips with it. The aftermarket rear silencer box had collapsed. Once revs were increased under load the flow through the box was seriously restricted but there was no evidence of this whatsoever on light throttle.
We would start with a general look over, compresion test, leak down and go from there looking for leaks, checking the secondhand headers were our handywork, checking the ACTs and see where the investigation would take us.

chet123

iTrader: (7)

Rickya, I've already got a 2.5" open bell mouth decat DP on the car already. Claims have being made that 2.5" is sufficient enough, although I'm in no doubt a full 3" system incl. DP will make a big difference.

chet123

iTrader: (7)

Have had a new pink exedy clutch fitted a year ago when the old one started to slip

MrNoisy

iTrader: (28)

What make of exhaust system do you have fitted mate?

chet123

iTrader: (7)

Afterburner down pipe, decat cat pipe and centre (non. Res) with ninja2 backbox. I am now considering a 3" down pipe tapered to the rest of the 2.5" system. Probably won't do this until my next turbo upgrade I think.

MrNoisy

iTrader: (28)

Sounds like it should be fine to me; you could always try a back to back test and swap out the backbox, but the Afterburner is what my friend was running and if that's good enough for 450bhp, it should be more than adequate to get you to around 350 I'd have thought!
Maybe the Ninja backbox is the weak point?

dynamix

iTrader: (3)

saw this inside a full 3 inch blitz system yesterday ...



Would actually struggle to see that it was 2 inch in there tbh. Quite a restriction.

ScoobyDoo69

iTrader: (17)

Was that the centre section or the backbox, Duncan? My Blitz doesn't seem to be a restriction