john banks

Sorry for picture quality, load up the Excel sheets and you can play with the numbers. Assumptions can be changed, [look out for automatic rescaling though which throws out the graphic overlay - now fixed]. Assuming 1.42 CFM/BHP for power/torque plots.


http://www.johnbanks.dsl.pipex.com/f...0Gsensible.xls

http://www.johnbanks.dsl.pipex.com/f...J25720Gmax.xls

[Edited by john banks - 10/25/2003 11:29:04 PM]

[Edited by john banks - 10/26/2003 9:23:14 AM]

hades

I'd often wondered about the idea of a 2.5 with that turbo. Now I want one!

Any ideas on where to find a nice cheap drivetrain capable of handling that sort of torque reliably

john banks

Sorry I should be clear these are projections not real results. But I expect I will run the sensible version (my gearkit is guaranteed to 450 BHP and 400 lbft. Assumptions include full density recovery, and that the turbine side can keep up. Andy F has got 440 BHP out of it on a low reading rolling road, so what it will do between 6000 and 7000 is anyone's guess. I think my flowed STi 5 heads should manage OK at least to 6000, we'll see. New versions with the scales locked so you can change the values without the rescale spoiling it will be uploaded to the original links in a few minutes. However, this does mean you can plot off the graph and won't see it.

[Edited by john banks - 10/26/2003 9:17:26 AM]

john banks

Here is "the smoothie".... 1 bar flat, I've assumed 3% higher VE than the 1.4 bar version because of reduced back pressure, of course compressor efficiency is higher as well. Don't know if it is even ball park, think it should be approximate. Hopefully this would not be too car destructive. If anything the torque may be conservative since with cats, smaller turbo, no FMIC, no water, standard ECU, the US version does only 21 lbft less. Using the bigger turbo and FMIC you might hope to hold the torque up higher up the RPM range.


http://www.johnbanks.dsl.pipex.com/f...0Gsmoothie.xls

john banks

The 16G is just too small over 6000 RPM, but with UK cams it could be very torquey and you'd not suffer too much at the top because it would fall flat anyway? Bit of a waste of the 2.5 though?


http://www.johnbanks.dsl.pipex.com/f...5716Gsmall.xls

dowser

We'll find out re. the stock td05 sooner rather than later....hopefully - but I'll also build up the 20 wheeled one while I'm doing the 1st mapping. I also don't think you'll need to wait until 3k for 1 bar of boost with the 05

Richard

EMS

John,

400 HP with only 1 bar...... I hope that will be true, but I don´t think so! I don´t think the VE will be that high at high revs with 2.5 liter capacity. But there is quite some room left in the compressor map to up the boost a little at high revs to compensate for the dropping VE!

Mark.

john banks

Trout has already had c.400 BHP at c.1 bar on an engine dyno with a 2.33 I believe. If the VE is too high perhaps my 1.42 CFM/BHP is too high also which would redress the balance? Sponaugle's plots at 1.4 bar suggest that at 1.0 bar it would be about 400 BHP in the high 6000s RPM (this is checking his results are reasonable because a stock WRX ran before him and made sane figures). Bear in mind the US STi 2.5 cam profile and the STi 5 cam profile (which I am using) are reputedly far better flowing than the UK/Euro STi 7s we've been used to which have quite naff cams for 400 BHP+.

Whatever, load up the spreadsheet and fiddle with the assumptions and see what comes out.

Here is a GT37 with rescaling to lb/min compressor flow, numbers more dreamy and unrealistic for stock internals obviously...

http://www.johnbanks.dsl.pipex.com/f...257Garrett.xls

[Edited by john banks - 10/26/2003 11:28:20 AM]

EMS

John,

Do you have cam profile details from the STi5 cams?

Mark.

EMS

The heads from the MY02 and MY03 Eurospec STi are the same. They seem to be the same casting as the "normal" WRX heads. I think the cams are holding it back to produce more HP, not very much lift. The US STi and Type RA cams are looking better.

P.S. The STi5 cams don´t have much lift either......

Mark.

john banks

Sorry my post vaped with too much editing trying to tie all the info together. Apparently longer duration and less lift might be better for power, certainly if you are revving high a lot of lift could cause float? This lot of course says nothing about the valves or the heads other than the cams.

STi 5

Intake: lobe height 45.4mm, opening 9 BTDC - 53 ABDC
Exhaust: lobe height 45.65mm, opening 58 BBDC - 10 ATDC
Base circle: ?

US STi
Intake: lobe height 46.6mm, opening (15BTDC to 5ATDC) - (45 to 65 ABDC)
Exhaust: lobe height 46.8mm, opening 55 BBDC - 5 ATDC
Base circle: 37.0mm

UK STi
Intake: lobe height 45.3mm, opening (29BTDC to 6ATDC) - (33 to 68ABDC)
Exhaust: lobe height 45.65mm, opening 58 BBDC - 10 ATDC
Base circle: 37.0mm

US 2002 WRX
Intake: lobe height 46.3mm, opening 10 BTDC - 50 ABDC
Exhaust: lobe height 46.2mm, opening 53 BBDC - 7 ATDC
Base circle: 37.0mm

Can't find the base circle for the STi 5 but assuming it is 37mm then the UK STi cams are not so bad in comparison, trying to find other details though. Anecdotally people are struggling for over 400 BHP on UK STis with the right turbo, but not on STi 5 heads.

Some info on NASIOC:
http://forums.nasioc.com/forums/show...light=cams+sti