redcarman

I am looking to get some advice on the mods that I am planning to my 87 951. The car already has a LR DP Wastegate, 3.0 FPR, LR MBC, a catless stock exhaust system, and MaxHP chips. I am planning on installing a catless 3" exhaust system and a LR QuadMAf this spring. My question is should I also upgrade the ingectors to #55 or are the stock injectors fine with this setup? Or is this something that I would only need if I upgraded the turbo as well? Thanks in advance for any recommendations.

Darwantae951

What are your horsepower goals? I upgraded to 55# injectors when I went to a MAF and DP wastegate running 15lbs of boost so that I wasn't close to maxing out the injectors.

V2Rocket

new injectors have the benefit of being well, new (and not 24 years old), and being a larger flow-rate means they dont have to work as hard as your stock ones do to provide fuel for your current power level. that said, if the stock ones are supporting your mods the 55's would provide some nice headroom in case you wanted to add some more go-fast shiny bits.

redcarman

Thanks for the quick response. I am looking to run around 15 psi of boost max. Not sure of a HP target - 260 to 280 maybe? Would the #55 injectors provide more power with my setup or are they overkill?

Darwantae951

The injectors themselves won't "provide more power." They will give you the ability to add more fuel when you decide to run higher than stock boost levels, and by having a higher flow rate, you won't run the risk of hitting the max duty of them and potentially running dangerously lean. As Spencer said above, it gives you more to work with in the event you decide to upgrade further down the road.

Scott H

I would say you need to upgrade the injectors anytime you're going for more power, just size them correctly for your end goal and have the proper tuning. The stockers will nearly max themselves out after a handful of mods. With your planned mods I would go to atleast 55#, maybe a bit more if you are planning more mods down the road and you want to future-proof.

m73m95

55# injectors will handle 95% of anything you'll ever want to do to your car. The only reason I chose 80# injectors is because there is nothing between 60# and 80#. I'm planning ~20lbs on a 2.8.... and occasionally E85 on track days. 60# would have run my engine/boost levels, if I didn't want to run E85....It would have been near their capacity, but they could do it.

Black51

What about 72lb injectors??

JohnKoaWood

Talk to Russel Berry, John Vitesse, Dave Lindsey, Chris White, Dave Mcgrath, Vic Power, or any of the tuning houses about parts selection vs goals.

They will be able to best advise you in selection of bits and pieces to make it reliable, usable, safe and most importantly fun!

Be advised.. speed costs money, how fast can you afford to go?

m73m95

The high impedance injectors I'm using only come in 60# and 80#

V2Rocket

WTF high-impedance? Why?

Darwantae951

Why not?

Tedro951

That, Darwin, was well played!

JohnKoaWood

DME injector drivers...

Not a problem with a stand alone system though!

Scott H

Rogue uses high-impedance injectors with his tunes, makes the proper software tweaks, and the DME runs cooler because of the reduced current draw on the injector drivers.