Thread: Autech GTi -SR20DE UPDATES

Jimmy, the bottom end is going to be basically stock minus the use of SR20VE 12.5:1 CP Pistons. The head has a heavy skim netting a 36.5cc combustion chamber, so careful HG selection is required to maintain a suitable compression ratio and also avoid chain slack.

My current set up with this head runs a 1.8mm Cosworth HG on flat top autech pistons, netting me around 11:1CR and sufficent P2V clearance.

Viprdude, you are right i am currently running JWT C3 cams.

I will measure the Nismo cams and see what specs i get, although i can tell you if they are anything like S3 cam specs they wont be going anywhere near my car!


Cheers.

For 13whp more than my DE with I/H/E and S4s off the nitrous I'm glad I didn't throw more money at the DE. Great numbers though. It doesn't seem like your stock rev limit is hurting your numbers, but I do notice that the C3s will still hold power higher up the rpm range. Have you looked into the C6M cams? With the headwork you have they should be a good match if you are able to remove your stock rev limit.

how long are your primeries ?

im liking your new build, high comp pistons and a tri y. you should hit your 200whp.

id put it together first with out the itbs and see what you make, then install itbs after its been running etc and see if you gain anything. im gonna guess you wont.

either way keep up the great work.

all motor is were its at !

stratton.

Thanks, i think?

Your DE made 173whp with that basic S4 setup? Cant really argue with that i suppose...thats a damn good result.

Although when you consider the small cost of fitting BC valve springs (like $100) to run a bigger set of cams and make 13whp more, it seems good value to me.

As already said, i guess the top end of the powerband was being held back with my mazworx header, as i know these cams can make power beyond 7,000rpm. This is the reason i've moved over to the B18 Tri-Y header.

The C6M cams are just beyond what i think is useable on a DE road car, but there would be more power to be had.





Cheers Stratton, the Mazworx header primaries are long! 36" long!

Ive pulled an old thread out here of some header testing done by Mike K which i think illustrates how the different lengths/designs affect the powerband: VE Header test done at last! - SR20 Forum

That header comparison gives a good indication of what i believe has been going on with my mazworx header, so i hope to pick up some top end from just moving to this Tri-Y header.

I dont think im doing too badly for a stock bottom end DE. You see SR20VE's with N1 cams putting out around 190whp, so i dont think my 186whp cammed DE is too far behind. Plus i make more torque than most stock 20VE's.

Why do you think i wont be able to make more power with the ITB's? If this were a stock unported DE head, i'd agree that i'll struggle to get beyond 200whp, but i have confidence that this head will flow enough to reach my goals.

Lets try it and find out i say.

Yes! Like I've said before the mazworx primaries are wayyy to long. Look forward to the header comparo

36" ridiculous. My own idea was 22-1/4" length.

while 36 is a bit long it does work well with a n1 cam. its maz's design and diameters that throw it off.

ive seen plenty of 36inch long headers do work. agian is it ideal no, but depending it can do the job well.

on a fully bolted or built motor the length should be spec'd to the set up.

stratton.

I was talking about my DE. If I wanted the compression bump that the stock autech bottom end gives I'd be spending more money than you because I have a USDM DE with 9.5:1 compression. Also, I didn't know you got the Janspeed head for free.

Does the B18 header bolt up? I'd like to see 200whp out of a DE again. Haven't seen one since Mike K and his Dog Car.

this^.



mike did it agian recently, with dai's car. i think he did 196 or something.

id have to search for the build, it may be on motoiq i remember talking to him about it when he posted it on face book.

stratton.

Considering the head porting on the engine, the independent throttle bodies...

Please use the C6M cams. I had forgotten about these.

I want a 250whp DE. I would not worry about the idle, as you can just bump it up. If this is a daily driver, forget it. But if it is a street legal toy.. i dont see any reason not to.

Do you have any head flow test #'s from this head?


*edit * The only major limiting factor i see here with going all out on this is the compression and fuel availability. you are running VE pistons with probably no custom valve reliefs, so C6Ms may not even clear that. However if you ditched them and went to a 13:1 CR setup the C6MS might be worthwhile.