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Thread: SR20DET powered Race Car - Advice Please

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2015-09-24 14:17:01
SR20DET powered Race Car - Advice Please
Hi everyone,

I have an SR20DET powered BMW E36 race car, coupled to the Nissan gearbox and custom prop and BMW Diff, I am club racing it here in the UK in the Classic Touring Car "Thunder Saloon" series.

I want to make some investment into the engine and drivetrain, but sadly absolutely clueless about Turbo engines, and anything to do with the SR20DET engine.

I have absolutely no clue which SR20DET version is it....

???? does that help ?

Currently my car has the following.

FMIC ? whatever that is....
Tubular Manifold
Apexi Air Filter
Nistune Standalone ECU
Gizzmo Electronic Boost Controller
Some type of aftermarket wastegate which I like very much already.
A new T28 Turbo
Mapped to 300bhp @1bar (no idea if that is good bad or ugly or whatever)
Exedy 3pack Clutch

I ran my first races this past weekend and the car performed pretty good already, plenty of grunt and mostly no problems at all.

Second race my exhaust developed a blow somewhere up front, not had a chance to look yet, but I also started to loose just a little boost pressure according to the gauge in the car, was pulling 0.9 where usually it pulled 1.0, it did still goto 1.0 but not quite as urgently.

I have absolutely no idea what the red line on these engines is, but I was pulling nearly 7000rpm on the main straight at Snetterton (UK) at around 132mph.....the by product of such a high RPM was that water temp was mostly 100c indicated, again, not sure if that is ok or not really.

Not a professional racer, not a professional mechanic, this is all DIY lol, hence lack of apparent knowledge.

So in my mind I will either be changing the final gear ratio slightly to lower those RPM's on the straight a little (short shifting and holding back the speed a little saw those temps come down to 90c/95c pretty easily), or I want to improve the cooling, currently has a large fan on the front of the engine, and two electric fans in the front of the nose.

Next thing is power....I was told 300bhp @1bar is very safe for this engine, however to be more competitive I would like to be running about 450bhp, the wallet is sadly tight, so any building or improvements will have to be gradual, with reliability absolutely top of the list, it must be reliable above all else.

I am prepared to spend money but want to spend it wisely.

Opinions and your experience welcomed.

2015-09-24 15:27:33
Brave man buying a car you know absolutely nothing about. Gluck!
2015-09-24 16:35:15
Well we completed a full day of testing, and a qually and two races with no issues, but now we need to learn about how to make the car better , only brave if things went wrong from the start I guess
2015-09-24 17:00:06
1) Looking at the coil packs, it is a S14 SR20DET
2) Redline it 7500 stock on the SR20DETs
3) S15 T28 will see 300WHP @ 1 bar (likely the turbo you have).
4) Themostat comes on a little over 80C. SR20s typically run at 180-190F. Fan comes on at about 187F (stock fans).
5) 100 C is a not over heating but on the warm side. My track vehicle typically stabilizes at 205 tucked up behind other vehicles (saw 210-215 with 100F ambient and volcano temps for on track temps). I also have a big intercooler and condenser in front. You are a little warm, but not quiet at head warpage (aluminum) temps.
2015-09-24 17:15:19
Thanks Lee,

Anything you can suggest to improve the cooling ?

I have twin fans between the back of the intercooler and the front of the radiator, and then the big fan with a shroud on the engine side of the rad.....maybe a larger single car replacing the two smaller fans or something ? does this engine respond best to air being sucked into the front or blown out, guessing it prefers being sucked in, but best to ask ?

Re: Upgrading power and etc ? any suggestions ?

Seen all sorts of stuff on the internet, knowing what is worth buying and what is not worth buying is another matter altogether tho.
2015-09-24 17:18:07
Ducting and a vent behind the radiator is what has worked best for me

Remove the fan between the radiator and the intercooler. That's impeding a significant amount of airflow.

Stick with two high flow fans and shrouding behind the radiator and duct the front end. It drops my track temps by about 10 degrees or so. Still have yet to vent the hood, but a good friend of mine with a big honking RB26 and a GT35R, saw a several degree temp drop at trackdays when he installed vents on the hood behind the radiator.
Last edited by Boostlee on 2015-09-24 at 17-20-32.
2015-09-24 17:47:12
Ok, sounds like a plan then, was planning on adding some GTR BMW style vents on the bonnet in any case to let some hot air escape, also planning on making a proper cold air feed to reduce heat soak on the air filter etc.

Regarding injectors, rods, pistons and all that business, what is a proven way to build a reliable 400 - 450bhp motor ? I am assuming all the internals on mine are std atm.
2015-09-24 18:30:48
Some of the GTR style vents are not louvered, so do little in actually evacuating heat and in some cases, compound the situation (high pressure zones over the hood keep the air IN the engine bay).

Standard internals are good for 400WHP. For how long on track, not entirely sure.

800cc sidefeed injectors (or 740cc NISMO or Sard Injectors)
EFR/GT/GTX turbo
Stock manifold
Induction piping
Good for 400BHP.

Easy button.
2015-09-24 19:22:09
I like it! Nice race car.
2015-09-24 19:58:52
sr20 bmw. i like.
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