I will be going to Dallas on 12-11 for a custom tune by TurboTrix. I want to get the most bang for my buck, so I will be installing a few things before I go for my dyno tune.

My current, relevant mods are as follows:

UTEC/Tuner Pro combo
TXS dp,cat delete,cat back
Hyperflow ic
RVM ic piping
Perrin fuel rail
HKS RS intake
Walbro pump
ARP head studs

I will be adding the following before the meet:

HKS 272in/272ex
AEM gears
Greddy belts

My question posed to TT was about injectors, and tuning on the new or old firmware. I had asked if I might need an injector upgrade before the meet. Right now I am running around 90% max on the injector duty cycle. With the upgrade of the cams, I was wondering if I may need to upgrade the injectors. Eventually I will have to do this, but I wanted to know if now is the time.

Mark's response:

My question to my fellow UTEC'ers is what do you think? With the 272's what would be a decent starting point on injector size? I don't plan on going with a turbo upgrade for at least 6 months, so I think 680CC or 720CC should be adequate for now, and maybe later. I also don't plan on running more than 24PSI at this time.

As for his last statement, I have read about the injector scaling in the threads here. I do understand that I can't just put 550 for stock and 680/720 for mod, as it will require some fine tuning. Any input here will also be welcomed. Thanks.

 

660's to 680's (The latter preferrable) You can bring them with you and let them drop them in prior to tuning so you don't have trouble driving there.. The bigger injectors may help you far down the line, but may ultimately make tuning your idle way more difficult until the UTEC gets some idle correction parameter features (Base Idle speed correction)

 

So are you saying that even with the scaling parameter within the UTEC, that if I go to bigger injectors I will have idle issues? I ask this because alot of people are having idle issues with the result of the straight 272s. I got the cam gears for the possilbe correction on this though (-4ex/-1in). I was going to work out those issues before the injectors were installed. The only problem I see is that even with the cams set to get a decent idle, it will never be as good or better than stock. Please explain further on the idle issues associated with bigger injectors.

Also I am looking into either the Greddy 660 or the SARD 700. Anyone here running either of these with little to no issues?

 

You should have no problems with the idle with the cams,injectors, and the Utec. I witnessed this done by Junior from Turbotrix this past weekend. He is an Awesome tuner and knows his stuff well.

 

I think I wasn't clean enough after I read what I wrote.. If your dealing with very large injectors (750 or larger) you might have have some idle issues that you would need to make other adjustments for.. you should have very little trouble with anything up to about 750cc.. Once you go larger they can be compensated for, but may require making adjustments to things outside of the UTEC's control (BISS/Idle speed, adjust the throttle cable or throttle position sensor etc..)

 

yeah. VTECH8TR was referring to my car as I installed RC 750 before the tune. It idels fine and drives fine. I didnt put the car under boost though figuring the car would fowl the plugs. Anyway. after the tune, the car idles like stock once the engine is up to operating temperature. If you ask Mark, he will tell you to set the cam gears to 0/0 becasue they tested different settings and found them to be no difference. I had mine at -4/-1 and we changed them while we were there.