LS-1 in a SandCar
Thread Starter
Teching In
Joined: Oct 2005
Posts: 8
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LS-1 in a SandCar Well it's not quite a Vette or Camaro but I hope I'm welcome here!
I have a couple of questions/concerns as I am new the the GM world.
I had a motor built for my sandrail, I was told that it has a .540.540 cam but that is all I know. It has a stock truck manifold on it with 29 lb/hr injectors controled by a mefi-2 or 3 computer. The fuel pressure is at 40 lbs. When I first brought it home it idled a little rough and sounded rich but if you hammered it, IT SOUNDED GREAT! and would come back down to an ok idle, real cammy sounding. I took it for a 30 minute test ride and noticed right away that under a load it fell on its face. After warming up I pumeped up fuel pressure to 52 adn the idle got worse but WOW what a powere difference.{Increase of course}
1.Can this ecu be programed?
2.Do I have to have O2 sensors? currently there are none.
3.Car don't idle as well even with pressure back down to 40. Have I damaged anything?
4.What would be the guess of the horse power?
any help would be appreciated and I am glad to be a part of the GM family.
I have a couple of questions/concerns as I am new the the GM world.
I had a motor built for my sandrail, I was told that it has a .540.540 cam but that is all I know. It has a stock truck manifold on it with 29 lb/hr injectors controled by a mefi-2 or 3 computer. The fuel pressure is at 40 lbs. When I first brought it home it idled a little rough and sounded rich but if you hammered it, IT SOUNDED GREAT! and would come back down to an ok idle, real cammy sounding. I took it for a 30 minute test ride and noticed right away that under a load it fell on its face. After warming up I pumeped up fuel pressure to 52 adn the idle got worse but WOW what a powere difference.{Increase of course}
1.Can this ecu be programed?
2.Do I have to have O2 sensors? currently there are none.
3.Car don't idle as well even with pressure back down to 40. Have I damaged anything?
4.What would be the guess of the horse power?
any help would be appreciated and I am glad to be a part of the GM family.
I assume you are using an LS1 pcm and not an aftermarket ecm?
1. Definitely! EFILive and HPT both make very good tuning & scanning products
2. In closed loop the PCM is looking for the results from the front O2s. You can tune around them, but life is much easier with them. Do you have a wideband to measure A/F?
3. You are probably rich at idle. Only risk of damage is from fuel washdown.
EDIT: I just reread and saw the Mefi set-up. I don't know jack about it. My answers to 1 & 2 were based upon using an LS1 pcm.
1. Definitely! EFILive and HPT both make very good tuning & scanning products
2. In closed loop the PCM is looking for the results from the front O2s. You can tune around them, but life is much easier with them. Do you have a wideband to measure A/F?
3. You are probably rich at idle. Only risk of damage is from fuel washdown.
EDIT: I just reread and saw the Mefi set-up. I don't know jack about it. My answers to 1 & 2 were based upon using an LS1 pcm.
Thread Starter
Teching In
Joined: Oct 2005
Posts: 8
Likes: 0
not very long
figured out real fast that there was a problem
i have it @ A D S in chandler arizona and they are tuning it
had to get a new computer that was tunable
they ran it on the dynometer with a wideband hooked up it was 10.2 to 11.5 @ idle and under WOT it went 17.1 @ 4700 RPM... hopefully they can get it tuned for me. also said 218 RWHP @ 4700 hope when its right it makes more that that!
figured out real fast that there was a problem
i have it @ A D S in chandler arizona and they are tuning it
had to get a new computer that was tunable
they ran it on the dynometer with a wideband hooked up it was 10.2 to 11.5 @ idle and under WOT it went 17.1 @ 4700 RPM... hopefully they can get it tuned for me. also said 218 RWHP @ 4700 hope when its right it makes more that that!
Thread Starter
Teching In
Joined: Oct 2005
Posts: 8
Likes: 0
OK. hashed out all the problems with tunable computer and software for the MEFI-4b which is marine application. *non sponsor* sells you a new computer with software embedded over the delphi. anyway it made 315 RWHP and 318 RWTQ both around 4800 rpm. took the car to the dunes and it pulled wheelies like nobodies bussiness. they also found that the valve springs needed to be change it started to die off TQ at around 5250 rpm and completely floated at 5900 rpm so thats my next step.
*non sponsor contact info*
talk to John or Greg!! after I replace the vavle springs with comp 918's I will take it back for a fine tune!!!
*non sponsor contact info*
talk to John or Greg!! after I replace the vavle springs with comp 918's I will take it back for a fine tune!!!
Last edited by horist; Nov 1, 2005 at 11:24 PM.
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I have an LS1 in my "sandtruck" with the stock computer, a T-REX cam and full bolt ons. Had the computer tuned by Wait 4 Me Performance. It does run a little rich at idle but screems at anything above that. My fuel pressure is set about 56-57 lbs. I am using the front o2 sensors. I just re-installed the mass air sensor to see if it helps to lean the idle some, we will see after the next trip to the dunes for turkey day.................Here is the truck:
Reminds me somewhat of the last sandrail I tuned, except this one had twin turbos hanging off of it. They are definately a blast and nice to scare the **** out of people!
http://www.public.asu.edu/~nicolasd/...ttls1sandrail/
http://www.public.asu.edu/~nicolasd/...ttls1sandrail/
