Thread: Timing opinions for rebuild

Vadim,

I'm trying to roughly and safely enter some top-end values for TP. My question is, since your max TP goes to 75, and mine is currently at 108... is your 75 value comparable to my 108, or is 75 75 no matter where it is on the map? What I'm trying to get at here is, should my values of the upper TP be similar to your upper (which is a lower TP), or should your upper TP be in the same place as my 72-80 portion and I have to continue tuning upward from there? Hope that makes sense!

Actually here is what I meant by TP values mean nothing when you don't know the other variables of the tune.

One thing I didn't mention is, if your max TP is 50 and your real TP goes up to 100, it will still stay on 50 Column and keep on using the values from it.

Are you going to be changing the injectors and MAF? Then your current TP scales should be fine.

To be on the safe side, keep the timing and TP scales fairly low, like max TP at 70. If you make the last TP column too high you will never reach it. Thus you might be in the lower columns where are not so safe for boost.

Yes, I am changing things compared to this tune. Don't forget the U13 came stock with 370's from my research anyhow, and with a similar MAF to a DE. I have already been running an N60, I never rescaled my TP for that, as I didn't know that was something to do. I did the VQ map and the K value though. This should effectively raise my max TP according to your words. With the rebuild however I am upgrading the injectors to GTi-R 444cc top-feeds with the GTi-R intake. Larger injectors lower max TP by your story, so do you think I should just leave the current TP map similar to what it already is?

Are you running resistors with those GTi-R injectors?

The TP is not going to be too much lower than. It's really hard to say on what the numbers will look like without doing some calculations. Even then I feel like they might not be too close to what you will get.

Nistune has a nice little injector resizing tool that updates the TP.

Now I did find this spreadsheet, make sure values make sense before you rely on them . : Larger Injector Worksheet (advice welcome) - SR20 Forum

Another interesting read from Calum, posts 7-9: "K" values and "null time" - SR20 Forum

There is a "boost sensor" in the stock GTi-R setup, although I'm not sure what it does exactly. But the Gti-R guys used to "punch a hole" in this solenoid to free-bump the boost to one bar (14.5psi, it's somewhere on the GTi-R forums).

My intercooler system must have been really bad because with the electronic boost controller off the T28 only hit 8psi.

The GTi-R FSM says to test the actuator for movement between 59 to 69 KPa (9 to 10 psi)

My 99 Sentra had a "Boost Sensor" in two locations. One was an actual MAP connected to the Intake Mani, another one was by the vapor canister in the back of the car.

Once I downgraded the ECU to a 96 one the MAP readings where no longer going through to ScanGauge so I got rid of it. I believe all newer emissioned cars required the MAP sensor (98-99 in our cases). On a GTi-R, they might have been used to actually keep track of boost .

Got the thread, it was just a controlled boost leak... Easy 1 Bar boost mod [Archive] - GTiROC





My 8 psi make sense since they say that this boost sensor bleeds 0.2 bar from the wastegate, effectively making the boost 0.7 bar, so actually the wastegate is only 0.5 bar. On my setup I didnt have this boost sensor (not needed anyway since I had a Greddy profec spec b).

Yes.



Interesting, don't think I'd ever punch a hole in anything to get more boost, lol! I'd probably just do it the right way.



Thanks for the read man. I'll look into it!