Well fellas, I am in need of some help with my HPT tune. Now there a few questions I need answered. Before you ask or say, yes I have looked at the stickys but I do NOT have HPT to view as I’m reading the them, so I’m not really understanding what’s being explained.

Last year I made 303hp and 286lb tq on 15psi on my current tune. I had some 680cc injectors installed with that setup. This time around I have 1100cc injectors with LOTS of other fuel upgrades, HO cams, and a custom Intake.

My problem is that I need to start the car to drive it to my new garage; however I do not want to start it on my current tune and wash down my cylinders. I need to turn down my injector constant right? With that, what else needs changed?

With the help of Mike MDLD9, he came up with the constant formula for me

So for your old injectors....680cc/min
0.20250 x (23.96/64.67) = .07502

So for your new injectors....1100cc/min
0.20250 x (23.96/104.61) = .04638



So, would that be ok to edit my current tune to .04638?
What else needs changed?

Chuck(03LSport) is going to be adding the changes to my car until I can get dyno tuned. He should be posting here in a bit.

Also, I can send someone my current tune to give me some pointers on other things I can change. I think I wasn’t tuned right and the car had more in it, I think my tuner got frustrated and just stuck me with something to drive.

I remember on the track that I was 10.0 afr at WOT. I knew that was wrong, but nothing I could do about it.

So, PLEASE HELP










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ

To add...
I have yet to scan his vehicle, but I do have his last tune. His last tune has the injector constant set at 0.16720. However, if the formula above is correct, the tune on his car right now should have the constant setting of 0.07502, right? To me, something does not seem right with the numbers. Also, I am not an HPT pro my any means. I have not had the time to fully get a good grasp on what HPT has to offer. I am definitely still learning as I go. My plan is to simply get this car drivable so that it can be tuned professionally, any help is appreciated.

Its going to want more fuel with the HO cams and the new intake manifold. But I think as long as you correct the injector constant and stay out of boost baby it while monitoring you afr, if you have that gauge, you'll be ok. Im no expert though but thats what I would do.

Thanks Chuck for chiming in.

Cory, yep I have a WB, I just want to drive it from once place to another out of boost. Then eventually up on a trailer.










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ

just vice grip the fuel line

i really have no idea i just wanted to wish you luck

LOL, sad thing is that when I read your comment, I was like "why would I do that?" hahaha










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ

You couldn't put the injectors it was tuined with in and baby it on over to get tuned then put the new ones back in ?

Good thought Nate, but I already sold them last year. I thought by now that I would have a tune for these injectors










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ

Are you still running a 97 ECU and program? You haven't switched to a 00+? Just asking.

I would like to see a copy of your tune. My guess is the tuner probably played with the constant and IPW vs Vac file and get it where he had it. So with that being true the constant you came up with will likely be way off, but who knows to what end.

I think I would start the car as is watch your WB and see what it idles at.

Do you have a AFPR?



FU Tuning

I never post on here anymore but saw your plight and wanted to help an old friend:

David, what is your fuel pressure currently set for? (Base pressure)

I have an injector constant from a few years ago when I ran my 1000cc RCEngineering injectors on a 1 bar setup... the only caveat is that I was running 25-26 psi of base fuel pressure with that tune but if anything it should get you close and get you to the shop to get it fully tuned. The car idled at 15.5 ish afr and drove around just fine, just a minor cold start problem when autumn came. If you have an AFPR (I assume you do) you can just dial your base pressure down a tidge and drop in my constant and it should at least get you VERY close.

Let me know if you're interested and I'll get you that constant #. This was run on a 1999 pcm setup @ 1 bar.

-Chris-


-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...