r/240sx

almost always something cool when i go by

Umihotaru PA, Crystal JP, Sky Lounge Food Court (Hakone Turnpike), Nissan Heritage Collection, Up Garage Yokohama Machida Flagship Store.

Bonus Silvia pic at the end.

Hey everyone! Recently acquired a S13 with a SR20DET. I have finally got it running and driving after fighting all the issues from the previous owner connecting the battery backwards.

Now that it's running I'd like to get it properly tuned (built motor and slightly bigger turbo). Any recommendations for trusted tuners in the downstate NY or NJ area?

Thanks all!

EDIT: Forgot to mention its running on a Link ECU G4X

Awile ago some dash wires got crossed and fucked my tachometer so it no longer works everything else does tho everything seems good looks like the damages went to the ecu anybody have any idea on the ecu tach signal and what is should test to see what’s wrong?

There is not much info on the subject, which was surprising to me after it happened on my setup that I consider quite common.

So I figured I’d share my experience with what’s called boost creep. A mechanical phenomenon when the wastegate is unable to bypass enough exhaust gasses in order to control boost to the desired level.

1st my car, I’ve had it for a decade but due to how projects sometime (d)evolve, only recently drove it for the 1st time since purchase.

It’s an S13 240sx with an S14 notch top SR20DET swap. Powerplant wise it has: K&N filter, full intake piping, stock MAF, Greddy intercooler, yellow 500c injectors, HKS GT2530 turbo, HKS tubular manifold, 3” catless turbo back, AEM fuel pump, unknown custom tune.

Doing my initial test drive, I noticed that power would increase exponentially as the RPM went up during full throttle. Looking at my boost gauge I saw up to 20psi.

Given that I’m running a stock WGA directly to a boost source, I was expecting to run spring pressure, so no more then 10. I blamed the unknown divorced pipe turbine outlet and got myself a bellmouth style one.

To my dismay it didn’t change anything. So I did the ultimate test, I not only unhooked the WGA, but also wired up the wastegate flapper wide open.

The 1st image is a Virtual Dyno datalog of that run, where you can see boost and AFR. Pay no mind to the dyno numbers, seems like the tach source is not translated properly and reading wrong.

I was miffed. Now way I would have thought possible to hold up to 20psi with the flapper held wide open but here I was.

AFR were still somewhat ok, surprisingly. But definitely higher boost then I’m willing to risk on a 30yo motor.

Only thing left to do, some DYI porting. Something I’ve enjoyed trying my hands at, including TGV deletes in my old WRXs.

I started by opening up the wastegate hole as much as I could, making sure I kept a good amount of mating surface for the flapper to seal against.

I then turned my attention to the inlet side. I mostly worked on the roof (where the hole is) by streamlining a more direct path and creating a smooth radius into the hole as opposed to a sharp angle.

Also flattened other casting marks and smoothed everything while I was there.

I was finally able to test out the mod. Result? Holding a solid 8 all the way through with the stock WGA on spring pressure.

I got myself a Grimspeed MBC that I will use to bring up the boost. Probably to around 13-15 since I don’t know what the tune was for. But keeping an eye on AFRs.