Injector size.
Instructor
Joined: Jun 2003
Posts: 100
Likes: 0
From: broken arrow ok
Re: Injector size. (devilfish)
Go to this site, http://www.racesystems.com, and download the performance calculator. It's free and will tell you what injectors you need for whatever horsepower your looking for.
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
Re: Injector size. (devilfish)
try your stock injectors first.
I know 24lb injectors will handle 420fwhp (easily) and you may be able to do it with 22lb injectors as well. all you need is a good fuel pump (walbro) and an adjustable fuel pressure regulator (good things to have no matter what injector you run).
if they work you'll save money and have better idle/drivability than big injectors would do.
if they can't flow enough then get a set of 26lb injectors.
I'm running accel 30lb'ers and making 475fwhp and I think 26lb injectors would have been better for me.
BTW, I just looked at your sig and saw that your running a ported TPI intake so I would try the stock injectors for sure. since your not going to be running past 6000rpm the duty cycle won't be as big a deal. as rpms increase the available time to fire injectors gets shorter, that when big injectors help most.
[Modified by ol,RJ, 1:31 AM 5/15/2004]
I know 24lb injectors will handle 420fwhp (easily) and you may be able to do it with 22lb injectors as well. all you need is a good fuel pump (walbro) and an adjustable fuel pressure regulator (good things to have no matter what injector you run).
if they work you'll save money and have better idle/drivability than big injectors would do.
if they can't flow enough then get a set of 26lb injectors.
I'm running accel 30lb'ers and making 475fwhp and I think 26lb injectors would have been better for me.
BTW, I just looked at your sig and saw that your running a ported TPI intake so I would try the stock injectors for sure. since your not going to be running past 6000rpm the duty cycle won't be as big a deal. as rpms increase the available time to fire injectors gets shorter, that when big injectors help most.
[Modified by ol,RJ, 1:31 AM 5/15/2004]
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
Re: Injector size. (devilfish)
ah thats a different story then.
the hot cam and LT1 intake will rev higher than a TPI intake.
so I doubt the stock 22lb injectors will work at WOT 6000rpm, but since the injectors on a LT1 intake are pretty easy to change it would be worth trying them. all you'll be out is a little time tuning.
If your expected flywheel HP numbers are acurate, 24lb injectors will handle it (with higher fuel pressure if needed).
I wouldn't go any higher than 26lb injectors though.
the real problem with bigger injectors is idle/low rpms, its hard to get them lean enough. add a big cam that makes less vaccume at idle and that affects the fuel pressure (less vaccume on the fuel pressure regulator at idle = more fuel pressure at idle) making it richer too.
so for street driven cars its best to use the smallest injector that is still able to do the job.
[Modified by ol,RJ, 2:20 PM 5/16/2004]
the hot cam and LT1 intake will rev higher than a TPI intake.
so I doubt the stock 22lb injectors will work at WOT 6000rpm, but since the injectors on a LT1 intake are pretty easy to change it would be worth trying them. all you'll be out is a little time tuning.
If your expected flywheel HP numbers are acurate, 24lb injectors will handle it (with higher fuel pressure if needed).
I wouldn't go any higher than 26lb injectors though.
the real problem with bigger injectors is idle/low rpms, its hard to get them lean enough. add a big cam that makes less vaccume at idle and that affects the fuel pressure (less vaccume on the fuel pressure regulator at idle = more fuel pressure at idle) making it richer too.
so for street driven cars its best to use the smallest injector that is still able to do the job.
[Modified by ol,RJ, 2:20 PM 5/16/2004]
