I'm rebuilding my L98 with an Eagle street performance rotating assembly. The guy I bought the motor from had the stock heads ported and polished and he also had them milled .080 and the intake sides milled .080 also. He had them machined for dual valve springs and it has roller rockers. The cam that came with the motor is a Comp 07-306-8 for an LT1. I'm debating using these heads and the stock TPI set up, but I'm wondering if I need to go with bigger injectors because of the bigger cam? I'm replacing the stock exhaust manifolds with headers too. Should I stick with the 22# injectors or upgrade to something like 24# injectors? I just don't want the motor running lean. I've heard that the ECM can compensate the pulse width to keep the AFR at 14.7, but can they only do so much?

 

I will say 24 should be fine

 

With stock heads depending on port job, likely looking at 220-240 cfm and 330whp possible with a good intake. Stock TPI wont get it done however. Up to 350 whp, 24's CAN work although at the 350whp area I'd rather see 30's for insurance and keep pump pressure lower. 24's with higher pressure can flow more but its harder on the pump.

You likely can try 22's with say 50psi pressure, and see where that gets you. Creep up on max rpm and monitor air fuel to see how it does. IF it needs more fuel, go get more injector.

ECM WILL NOT COMPENSATE WOT FUELING. MAF systems can only do so much before they get pegged and unable to read incoming air. Dont expect to put that cam in and run without a good chip tune. It may run ok part throttle and such, but it will need work to idle right and at WOT. A Few cases WOT is close enough, but its rare to see. I dont expect this to be one of those close enough cases.

 

I was planning on using the stock TPI, maybe getting some SLP runners. All the aftermarket TPI intakes are so frickin expensive. The mini-ram is outrageous, imo, plus you gotta spend another $400 on their fuel rails. The Edelbrock intake is like $800, and it doesn't even come with an upper plenum. I wan't to get a set of injectors from south bay, because I'm pretty sure they're original, and right now the car runs like crap. I'm not about to use old crappy injectors on a freshly rebuilt motor.

 

Gotta pay to play intakes arent cheap but do make power. Miniram is way overpriced but its custom made low volume supply so its gonna be pricey. Which edelbrock you looking at? Intake and runners for tpi fit stock plenum. Pro flo xt is a better intake for hp but needs specific tb, lsx style.

Stealth ram is a good option for 650-ish with custom adapter lines. Not a bad way to go

 

Hello Michael
give us a shout so we can talk about the flow rate for the injectors.

www.southbayfuelinjectors.com
516-442-4707

 

At $330 for the just the runners you are half way towards the cost of a HSR intake that will blow away any big tube runner TPI setup

http://www.summitracing.com/parts/wnd-7540/overview/
http://www.summitracing.com/parts/hly-534-186/overview/

or budget fuel rails even cheaper
https://www.thirdgen.org/forums/alte...tive-fuel.html

 

Don't you have to cut away at the hood for the HSR to fit?

 

On a bird, possibly. On my iroc i had to trim some of the hood bracing due to contact with throttle body but i had poly engine mounts which did raise things a tiny amount

 

Also, will the HSR work with 87+ heads? I noticed summit says it will only fit up to 86. I'm assuming that has something to do with the center bolt heads?

 

Don't believe everything you read online

My HSR has the 4 center holes slotted to suit either style head
No biggy to elongated the holes anyway if you get one that has wrong holes

 

If you want to go fast, get a stealth ram, about the same cost as slp runners, and with much more potential.

 

A couple angled shims will allow the steath ram to work with the later intake bolt angle.

 

I was just going to say that by increasing rail pressure, you increase injector output and improve atomization. However, as Orr eluded to. the stock pump will not support this type of system. You need big bad fuel pump(s) to support constant high pressure operation. A set of 30lb/hr injectors from south bay is alot cheaper. (Ive got big bucks invested in a dual pump fuel system, but then I'm a little nutty)

Also, your OE injectors can't be trusted to support high horsepower and not lead to engine damage from injector failure. Ive watched a demonstration showing how the stock (Multitech) injectors dropped out at 70psi. A good set of Bosch IIIs will operate consistently up to 80psi without dropout.