rhodes_96_2

Mate, it looks like you are going to need some tuned length pipes to take advantage of the extra puff the larger turbo is producing.

mutant_matt

What do G-Force think the problem is?

Matt

john banks

There are so many factors to control when comparing two cars like this to be able to easily comment.

A possibility is that the hotside (turbine wheel) of the turbo is the limiting factor.

If you don't change this bottleneck you don't make more power, you just raise back pressure and reduce flow.

The only way to find out is to try another turbo on the same car.

Other thing you could try before that is to try running the same boost at the top end as the VF35 and try to advance the ignition. 1.4 bar at the top end on a VF turbine with a P18 housing lost me power - it was sweetest at 1.2-1.25 bar, and the sort of power figures you are at are about what you might expect from such a small turbine wheel.

Flow is about the hot and cold sides of the turbo and they need to be sized correctly.

[Edited by john banks - 9/26/2003 9:45:25 AM]

R19KET

John,

It's very confusing. The same turbo is making 391bhp on Alan McRae's car, and 396bhp on Jonno's car, both at similar boost.

The MD321 has a Garrett GT30 core, 52 trim wheel, and the exhaust side is massive compared to a TD05, let alone the P15/IHI exhaust wheel on the VF35.

IIRC, Alan's car pulls 1.5bar at well below 4000rpm on the road, so I'm not certain why it's so late on Conrad's car. Having said that, John said that his spools up much earlier on the road, than is indicated on his graphs.

355bhp from a VF35 running 1.2bar is amazing.

I've made a few suggestions to Conrad, so we'll see what happens.

Mark.





[Edited by R19KET - 9/26/2003 11:26:36 AM]

john banks

Is indeed puzzling, didn't realise it was a Garrett core and cannot remember all the MDxxx numbers, he said P18 "wheel" so I presumed wrongly it was a VF turbine in a P18 housing.

So it is clear the turbine is not too small so we can rule that out.

john banks

How about:

Leaking manifold/uppipe
Blocked cat if you have one
Leaking dump valve
Intercooler holed/leaking
AVCS not working

aus73

I am just curious as to where some of these problem areas come from?

If the manifold/Up-pipe was leaking, or the dump valve was leaking, or the intercooler was holed or leaking the two cars would not achieve an identical boost curve - or would have major problems at idle with these air leaks.

The car is a de-cat, although the up-pipe was changed at the owner's request as he had been un-reliably informed the STi 8 has a cat before the turbo - I guess from somebody that has never worked on one.

The AVCS works on both cars - and the map is almost identical between the two cars.

There is one big difference between the two cars.........

Johnno's car was run here on NF octane booster with Optimax. It will be around 101-102 octane - as opposed to these two cars which are run on Optimax. Decent race fuel or an octane booster mix will give an extra 10% bhp and torque (roughly). Johnno's car made 398.2bhp and 350 ib-ft. Apply the same principal to the STi 8 in question and see what you come up with - 315 ib-ft and 362.3bhp.....

I'd like to stay and chat a bit more - but Steve and I have an STi 7 to map - on the standard turbo..........

Sorry if this sounds a little short - but there aren't enough hours in the day.

Chris Davies
G-Force Motorsport Ltd.

P20SPD

iTrader: (1)

Re the up pipe leaking, it would not affect idle IMO, but would affect boost and spool up and top end.

**** what do i know?

Steven

Trout

iTrader: (1)

To get 101-102ron requires a lot of NF - half a bottle?

Certainly never seen a normal amount - e.g. a one shot produce anything like a 10% power increase. This is also reflected in the performance testing of my own car - on both the dyno and doing quarter mile runs.

Rannoch

Andy.F

I have

NF helped my car make 440 bhp, it made 408bhp on Optimax at the same boost (1.45bar) with less advance. So not far off 10%

A recent turbo I supplied to someone in Europe made 60 bhp more using C16 race fuel (and appropriate map) than it did on 98 octane pump fuel

Andy

The Fixer

Been out in the car with the guy who has looked after and mapped by bikes for years, on the road compares realistically with the graphs, the car really doesn't get going untill at least 4500rpm.

One thing he did point out was that the outlet of the turbo (compressed air side) was longer than the standard turbo and as such the hose from this point to the intercooler hard pipe went through an over exagerated "S" shape, almost flatening the hose, could this be a restriction?

I have spoken with Steve (who mapped the car)about my hot start problems and these are going to be addressed when I return from Africa in two weaks. His opinion (Steve, correct me if I'm wrong please) was that the turbo simply did not flow the required amount of air to produce 400 & above as the APS SR40 Turbo does on G-Forces demonstrator (404BHP on Optimax)?????

There is definitely no leaks on up-pipe etc.....
Interesting point though would be a leak on the compressed air side, bleeding air off, Dump valve is APS recirc then Atmos at higher pressure version. Where is the pressure on the graph red from? Post intercooler or before it?

Mark, do you have the compressor map for the MD321? What CFM of air is it supposed to flow at what pressure?

I'd like to compare this with the APS SR40 compressor map, Chris can you provide the APS map please?

As Mark pointed out above, we have also had discussions and things will be looked at when I return.

Any other thoughts?


Conrad

PS On another note John B, I have a set of those SR20DET injectors as they didn't fit if you know anyone who wants them, brand new & unused.

Bob R, can you explain to me why you thought the APS dump valve didn't work and recommended the Forge Recirc Item instead? Could it be something to do with the problem I'm having?

[Edited by RSVR Racer - 9/26/2003 3:59:48 PM]

David_Wallis

That turbo does flow enough air for 400+ bhp..

Id be interested in seeing the fueling and timing maps for both cars too..

David

marcin@klubsubaru.pl

I believe I have a similar problem, although my car is not an STi but fully rebuilt GT. Went to the dyno and made the first run before any mapping - damn, it's 305 bhp only And the spool-up is far from what I expected, and turbo maxes out at 1.4 bar, very much lower than expected.
As the dyno is 350km from where I live and we could only be there for few hours we concentrated on mapping. We reached 330 bhp on 98 fuel and than changed for Elf TurboBoost. Final result - 374 bhp on elf and it's I think 29 deg advance on that fuel.
Not so bad, but not satisfactory so the car went back to the garage and my mechanics found leaks on almost every joint in my Greddy FMIC piping. Got that fixed, spool up is quicker by app 200 rpm and turbo reaches 1.5 bar but still not where it should be. Checked the turbo, wastegate etc and finally we found that my Gruppe-S collector has a significant leak on the joint in the middle. We found it yesterday in the evening so I don't know the results of fixing it yet, but tomorrow there is a final round of 1/4 mile championship, so I will know the time, but won't know the rr result for some time.
Anyway - I was told that I can't just weld those two pipes because the collector will break and I'm afraid that any other solution will be only temporary.
I hope to go to the dyno soon and present a chart which would reach above 400

The Fixer

David, could the APS Cold Air Intake be starving the turbo? Surely the turbo can only generate sufficent pressure if its fed with enough air? or am I clutching at straws?

I will say one thing about the map, the car runs very well whilst on boost, no hesitations, glitches or anything out of the ordinary. ??? So surely the fuelling is OK??? Maybe too much ignition retard?

Or am I just clutching at straws?

I will try & get picture of "S" bend pipe so you can see what I mean....

Conrad

R19KET

Marcin,

I'd check the flanges that bolt to the head too. When we checked the flanges before fitting a set of Groue-S recently, EVERY ONE needed sorting out.

Andy, how much NF did you need to get the 10% increase ?

I can see how the Elf race fuel, that costs circa £4.50 + vat a lt over here would give 10%, but it would seem a little optomistic with 60ml of NF in a 60 lt tank. A bottle of NF to a tank may do it though.

Conrad,

I will email you.

Mark.

The Fixer

My Headers are the standard ones, only changed up pipe to tapered APS cast version.

Mark, please send to conrad_bradley@yahoo.com

[Edited by RSVR Racer - 9/26/2003 5:42:49 PM]

[Edited by RSVR Racer - 9/26/2003 5:52:54 PM]

The Fixer

Here is a few pics from under the bonnet. *PICTURES REMOVED TOO BIG* Links placed instead. CB

The dodgy bent "S" pipe...Restricting Turbo Outlet or Not?

click here

Turbo Outlet Compressor Side.

click here

Exhaust Out Side.

click here

Samco Induction hose & Part Of APS C.A.I. Kit

click here

Generally under the bonnet.

click here

APS Cast Tapered Up-pipe

click here

APS Dump & recirc valve.

click here

APS Cast High Flow Turbo Outlet

click here


Bodged Electrical connection, Subaru plug to 3 bar Map Sensor, anybody know where I can get the correct plug to remedy this?

click here


Bloody hell the pictures have come out BIG!



[Edited by RSVR Racer - 11/11/2003 7:44:41 PM]

john banks

Bottle of NF to a tank had about +10% for me too.

Bob Rawle

Well the APS bov leaks, the piston has (or had) no piston seals in it so as you try and come on boost there is a leakage path from the top (adjuster) side of the bov, its pretty hopeless and does restrict spool. Also affects the build up of pressure on cruise and so affects the way the turbo spools from cruise as well as rolling road runs. Since its leaking there is then always a pressure differential across the valve when there shouldn't be. I spoke to APS about this two years ago, they didn't want to know at the time offering to prove the bov was superior using their 250,000 dollar rolling road .... lol. A well set up Forge recirc will gain you loads of rpm wrt turbo spool in comparison.

I suspect the other reason for your low top end is the std headers, Jonno has HKS headers and that makes a huge difference to mid and top end, they are not as lively in the mid but, his torque curve is very classic shape (or was with factory ecu) making 385 bhp with EcuTek remap. the turbo still had more to come from it at that and was holding 1.25 bar as mapped.
Maybe I'll ask John to let me prove the point some time. What internal diameter is the up pipe, does it match the turbo, whats the surface finish like internally, how well is it lagged, all this will again affect turbo spool and how well the engine responds. The exit pipe is not helping, ask whoever installed to do it right, only needs trimming by the look of it. Also is the APS CAK pipe diameter smaller now ? Looks like it, if so another difference and a possible contributer to the difference to Johns car.

I've spent a lot of time working with the '321 and I'm suprised to hear it said it can't get to 400 bhp, not true in my view, as with any turbo its only good in the right setup, if the components don't suit each other then the results don't come and its not down to any one thing. saying it "won't flow air" is inaccurate in my view and a bit misleading.

My offer to do an unbiased assessment of the SR40 still stands open, if someone would just let me know when. if its good I'll say so.

So sort the bov and headers and exit pipe out then you stand a fighting chance.

cheers (no axe to grind just advice)

bob

edited to add that I doubt John is running with 102 ron, maybe 100/101 at a push depending on the base fuel quality and at that it won't buy you 30 bhp just like that, serious remapping needed in the ignition area.

[Edited by Bob Rawle - 9/26/2003 7:49:06 PM]

David_Wallis

My two pence is..

I dont like the up-pipe..

I dont like the downpipe..

and I dont like the intake path.

What ecu are you using..

agree about heat wrap..

And as for the s shape, its not killing the power, but again I dont like it.. Its not Ideal.

Too many joints.. in the D/P and U/P for my liking..

Just my two pence.. and 100% agree witb aps dumpvalves.

David

P20SPD

iTrader: (1)

Big enough pictures, i only have 56k at home, gave me time to go get a drink for me and Emma

I agree with David, i dont like all the joints, more places for leaks IMO. I personally dont see the need for all the joints. APS dump valve is sh1te IMO. My car was terrible with it on.

Neither can i see the need for the short cast turbo outlet, why??

I cant believe your struggling for boost on this turbo, in reality your car does not have much different mods to mine, and my turbo, an MD304, will hold 1.3bar all day long.

By comparison, your turbo makes mine look like a puppy, so you should be making the power, especially at 1.5bar.

There is definately something wrong, cant say what as i am not that technical, but i know there is something wrong.

Compare your spec to that of Gadget Daz's in Japanese Performance, and you should see what you should be getting.

Steven

[Edited by P20SPD - 9/26/2003 8:51:15 PM]

PSI3

"Bodged Electrical connection, Subaru plug to 3 bar Map Sensor, anybody know where I can get the correct plug to remedy this?"

Yes, i have those in stock, call or mail me.

Simon
07796 992992

The Fixer

Bob,

Bob, thanks for your comments, I actually bought the Forge Motor Sport Dump Valve but was told it was "too small" and would have to be mapped around, hence I went for the APS one. I still have it and so may try that also.

Interestingly the G Force demonstrator has HKS headers, would be good to see what happened if they went back to the standard versions.

Turbo exit hose, I thought about cutting back the intercooler hard pipe and getting a straight length of samco tapered hose (turbo outlet is one diameter, hard pipe is another) to give it a more straight run.

Uppipe is a cast unit which is tapered, this combines with fexible hose (smooth finish inside)

Not sure if the CAI pipe is smaller than a previous version as I've never seen one but I have got the non standard large BMC filter on rather than the little APS version.

David, what dont you like about the intake path, two long or two small? ECU is GEMS.

Stephen, Sorry about the pics m8, just uploaded them from my cam, didn't have time to edit the size. Get yourself on broadband! Yorkshire blokes, tight as.....oops! lol

PCB. please drop me a mail re:connector, I want the car to look like it was original. Cheers.

marcin@klubsubaru.pl

Mark, all the flanges needed some work and they don't leak anymore.
Just came back from tests - after the collector was fixed we noticed a small (if any) improvement. After that we checked the GFB BOV and it leaked. Replaced and the test drive gave us .4 bar @ 3000, .7 @ 3500, 1 bar @ 3800 and 1.6 bar @ 4100. Held to above 5500 and then about 1.5 (or slightly less) up to 7000. Run out of time and ideas - even checked with the brakes servo (is it the right word?) disconnected from the manifold but no more changes. There are no leaks in the FMIC and it's piping, no leaks on the hot side so if there is any then it must be the inlet manifold or throttle. But fixing all the minor leaks finally gave some results. I will report my times by Monday.

Trout

iTrader: (1)

Andy,

I didn't say I hadn't seen NF produce another 10% of power - I said that with the normal one shot - half to a bottle per tank would give an excellent increase in power - possibly even 10% - if you want to run a bottle a tank!

On my car the results were not quite as good as that - although I was running WI - which gave the same level of advance as a whole bottle of NF - then it was diminishing returns.

Am surprised at the results on RSVRs car - also surprised at the results on the standard turbo!

Rannoch

tweenierob

What are the downsides to running a whole bottle??

Rob

Andy.F

Price

Rannoch

I was just trying to throw some light on why Jonno's car had produced some 10% higher results than the Sti8 (assuming the Sti8 was on plain Optimax)

Andy

[Edited by Andy.F - 9/27/2003 8:03:42 AM]

Trout

iTrader: (1)

Andy,

fair point - but do we know how much NF Jonno was using?

Rannoch

Bob Rawle

Rannoch, I've given a bit of a clue on that.

Also think about how much timing differing amounts of NF allow over and above straight Optimax. I can only comment on Johns car as I've seen it but its "a good one".
These cars vary tremendously in their ability to run boost and timing without det irrespective of turbo, and anything else so its not suprising to me to see cars vary like this.

John also uses an oil catch tank.

David_Wallis

if gems doesnt use a maf.. then I would get a filter as close to the inlet pipe / turbo as possible.. get some ducting for cold air..

unnecessary restrictions..

im sure andyf once said 'as smooth a flow in as possible'

Port the std headers??