Jam Performance

iTrader: (3)

Whats the max bhp anyone has ever achieved with the old black slanty intercooler??Is it possible to gain over 300bhp with full supporting modz including apexi power fc mapped by a top mapper

Tidgy

the intercooler doesn't give you any direct performance parsay, it just keeps inlet temps down, so on hot days you'll loose a hell of alot of power

Jam Performance

iTrader: (3)

so my power figures or torque wont be affected in anway on a dyno ?

Tidgy

the newer one iirc is slightly larger, so reduces inlet temps. but on hot days aftera few mins of driving they get heat soaked and you loose roughly 1 bhp per 1 degree (and engine temps can increase temp by 50 degrees).

if your lookjng for 300 personally i'd go for a front mount

R4LLY

iTrader: (1)

Your dyno figures will all depend on the coolong capabilities of your chosen Dyno. However it will still be difficult to get over 300 without changing to a front mount or bigger topmount

Normski

I have a STi slanty intercooler (silver), and my car makes 307 BHP. Japanese Performance magazine had two project STi Ra's with the same slanty intercooler as mine and they made 330 BHP on the both of them.
I'm not sure of the difference to the Wrx intercooler, but you could pick a STi one pretty cheaply.

ZEN Performance

Make no mistake, the intercooler has a very real and direct affect on power, and also spool up.

A small ineffiecient intercooler will hurt spoolup due to reduced charge density, just as much as an overly large intercooler can hurt spoolup due to excessive volumn to fill

It is possible to get over 300hp, but on the PowerFC which doesn't have knock control it's going to need to be mapped conservatively do it doesn't det with prolonged WOT. I would say 280hp is the safe limit, but you can never tell. Usual rolling road results caveats apply.

dan83590

The early silver STI one is slightly larger and flows slightly better. The pipework to the STI IC is different too and also flows a little better. The flow difference between the two is very small. Both will swap like for like though.

RA95

My RA pushes mid 300 bhp with a slanty intercooler (conservative dyno @ 333bhp 98RON 1.35 bar - but I run 1.5 bar with CVL booster 102RON+). Significant engine, fuelling mods as well of course, APEXI PFC/AVC-r.

The intercooler is by far the limiting factor on my car due to heat soak, I could fit a front mount and get significant timing advance probably.

Tidgy

once mapped for spool up is not much different on front mount to top mount.
lets face it though, top mounts are ok, untill the engine warms up, then there about as much use as a chocolate tea pot lol.

StudentScooby

If this is the case then why do subaru still make the new cars with them! surely they carnt be that bad can they!?

Tidgy

who knows.

y have mitsubishi switched to front mounts on the evo's?

ZEN Performance

Subaru have improved the TMIC as time has gone by, the latest STI ones are very good.

robsw

The increase in flow between the WRX slanty with WRX feed pipe, and the STI slanty with STI feed pipe, is 80cfm. This equates to an increase of 56% in flow, which is quite a lot in my opinion. Found the info here...

AutoSpeed - Top-Mount Trial - Part One

ZEN Performance

that doesn't mean much at all I'm afraid.

dan83590

Did you not read this bit?

This imported Version 2 STi intercooler is a rare find. Visually, only the silver finish and a different rear end-tank shape distinguish it from the contemporary WRX part. So how much better does the STi intercooler perform? Well, not much. A slightly larger charge-air entry into the rear end-tank allows a tad more flow than the standard WRX 'cooler - 285 cfm versus 282.7. Thermal mass and core volume, meanwhile, is identical to the stock WRX - pretty minimal.

While the STi intercooler holds a slim flow advantage over the base product, its cast alloy/silicone hose feed pipe flows considerably better than the standard plastic part; the absence of a convoluted section (which causes massive in-pipe turbulence) is the major reason for this improvement. Once bolted together, the STi intercooler and feed pipe assembly outflows the standard WRX combo by more than 50 percent - a good net gain. Note that the Version 2 STi feed pipe won't bolt onto the conventional WRX intercooler

I've read this before, very interesting indeed.

robsw

Please correct me if I am wrong, but I think it means the STI set up flows better than the WRX set up, which isn't really surprising I know.

robsw

Oh, and in case anyone is interested here is the concluding part of the intercooler test. It has been posted on here before, but for those who have'nt read it.....

AutoSpeed - Top-Mount Trial - Part Two

The Chief

I know someone who has a Spec C and is running a reliable 400bhp with his top mount. and technically he really knows what he's on about, above that ok maybe invest in a front mount, but i'd say up to 400 you'll be ok.

dan83590

Mmm. The chart at the end is interesting. The early slanty STI intercooler with O/E feedpipe attatched is on of the best. Thats a surprise..

robsw

It is a surprise, I am thinking of obtaining the early STI intercooler and feed pipe for my 93wrx, as it is a direct swap, so no need to butcher a fmic or a later spec tmic on to my car.

I know that later tmic intercoolers will have better cooling properties, but I do not track my car, and the roads around me only allow the odd blast here and there, so it should suit my needs.

kbahus

Just wanted to chime in. I had the stock slanty intercooler on my swap and just upgraded to a Forester XT intercooler. It actually made a significant difference in spool up and overall performance. I also picked up about 2 psi of boost without changing anything (had to turn it back down due to lack of injector). I highly recommend this conversion.

robsw

Nice work!

kbahus

Thank you!

harvey

iTrader: (48)

Rob : Thanks for posting these interesting links. I was going to ask where I could find part 2 but you had that covered.
How can I subscribe to Aotospeed.

I think some of you are missing the point. I guess, if you have a 500 bhp engine you can put nearly 500 bhp through a top mount or something approaching that for a very short time.
To operate reliably and efficiently your engine needs low temperature charge air. The turbo compressor supplies hot air that must be cooled and the more boost you run the more heat there is to get rid of. Hence the need for some form of intercooling on turbo engines.
Hot charge air results in poor power output but the engine does not like hot charge air which can also result in DET and that can be terminal. A big hole in your piston and bank balance.

I monitor ambient temperatures and charge temperatures on my cars and have fitted this equipment to numerous other cars, not just Subarus. The charge temp guage, harness and sender is change out of £50 including postage.

Until you have monitored charge temperatures on a Subaru with TMIC, you are in the dark and may find some of the very high temperatures hard to believe unless you see them yourself. I believe that a signifigant proportion of Subaru engine failures are because of prolonged high speed running with inefficient TMICs

The guages I refer to stop reading at 69.9C.
On an STi 3 Wagon (335 bhp) not many mods, on a sprint from 0-140mph, the guage is off the clock well before 140mph. On hard cross country driving the guage is similarly off the clock with plenty WOT. Motorway cruising may be 6-12 C over ambient.
With a good FMIC, M-Way cruising may be up to 2 C over ambient and a maximum of 12 c over ambient cross country and I have had 20 C over ambient on a very hot summer day on track at ten tenths for 25 minutes.

Bear in mind that the scoop and TMIC have improved from the STi3 but I have seen frightening figures on an STi7. I am now looking for an opportunity to monitor STi8 figures.

robsw

https://autospeed.drive.com.au/cms/access/join.html

Harvey, follow the link above, you have to register first before you can subscribe.

Thanks for the interesting info on charge temps, I have heard about high inlet temps on Imprezas before, seems like it is something that is worth monitoring. Where can I get the temperature guage etc from?

harvey

iTrader: (48)

Thanks for that Rob.

I was getting these gauges from Nomad but he stopped doing them and I now get them from Mike Rainbird at R&B Motorsport, Norwich. 01508 557822. Fax 01508 558011 or mike@randbmotorsport.co.uk and he has a website R&B Motorsport.co.uk | Suppliers of everything you need for your trackday or fast road Ford RS vehicle. .
A word of caution. Someone sent me to a link on e-Bay where I could get a very similar gauge for around £26 posted. They did not take credit cards, only cleared cheques or postal orders. After I ordered one none of my e-mails were answered and then I had a couple of PMs and e-mails from guys on this board who had purchased on e-Bay and had nothing but trouble. Further e-mails remained unanswered so I cancelled the cheque and was then threatened with being reported to e-Bay and blacklisted etc.. I encouraged the guy to do that and I would highlight my experience and e-mails received etc. etc.. After numerous more threats I heard no more and as far as I know my e-Bay record is still 100%.
The company was somewhere in the Leeds/Huddersfield/Wakefield direction.

I do feel that if I was not monitoring the temperatures on the STi 3 Wagon there is a good chance I would have killed the engine by now.
I have also just completed a series of tests involving bonnet scoops and this has been very interesting.

robsw

That is brilliant Harvey, thanks for the contact details. Sounds like a very good idea to keep an eye on inlet temps, especially if I am using an Sti version 2 intercooler. I would enjoy reading a write-up on bonnet scoop testing, if you ever divulge your findings.

harvey

iTrader: (48)

Hi Rob : Quite happy to divulge my findings. No secrets.
The guage goes off the clock at 69.9 deg. C and with the STi 3 intercooler and OE scoop and a sprint from standstill to 140 mph the guage was off the clock well before 140 mph.
With the STi 7 scoop it was still off the clock but the temperature rise was a little slower and heat soak from traffic lights or whatever dissipated quicker. In the cruise on the motorway the charge temperature was down a few degrees, closer to ambient but only slightly. The STi 7 scoop was also working a few mph before the STi 3 OE scoop which was noticably working at 60 mph.
Now with the STi 8 scoop on the 0 - 140 sprint on a cold day the temperature on the first run was only 55 C, the scoop was working below 50 mph, heat soak dissipated much quicker and in the cruise temperatures were to within 6 degrees of ambient.

My overall impression is that the STi 8 scoop was a big help but I don't think it was the full answer. These tests were done with typical ambients between 2 and 6 C. so in summer even with the STi 8 scoop, charge temperatures will soar far higher.

On my front mounts I typically see 2 degrees over ambient in the cruise and except on track, no matter how hard I drive I rarely see more than 12 degrees over ambient.

My conclusions are that the benefit from the STi 7 scoop did not warrant the expense but the benefits from the STi 8 scoop were a very good stop gap measure in advance of fitting an FMIC. As I said to David Reid of D R Motorsport sales@drmotorsport.co.uk who was kind enough to loan the STi 7 and 8 scoops, I would not have believed the improvement from the STi 8 scoop if I had not conducted the experiments myself. I must also say I would not have believed the VERY high charge temperatures on the OE setup had I not gone to the trouble of monitoring them in the first place.
I was well enough impressed with the STi 8 scoop that I bought it although I will fit an FMIC if I keep the car.

Tone Loc

iTrader: (1)

Harvey, just looked at R&Bs website and the sensor they supply is screw in. Where have you mounted your sensor and was this screw in?

I'm interested to see how the long and thin MY06 WRX intercooler performs.

Tony.