A while back I dynoed my stock truck with just the whipple installed & got 314hp & 368#tq. After adding a new intake, cat-back, headers, colder plugs, & electric fans I went to redyno my truck & after dynoing it I got 326hp & 390#tq. I was hoping for some better numbers but I wander if my problem is because of torque management pulling timing out during the whole dyno run since my torque stayed above 360# all the way to 4800rpm. Doesn't GM set the maximum torque values somewhere around 360-370#.

 

Those are pretty good numbers I'd say. I bet your problem is more with knock retard than torque management. From what I've seen and experiences, torque is much higher with the whipple, but falls off fast, leaving a lower HP number. I'm sure that with that much torque, its fun to drive. Does it feel like it starts falling flat when you get into the upper rpms?


Have you logged any time on your truck with autotap?

Did your dyno run have a wideband O2 sensor hooked up?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2ksleeper:
<strong>I wander if my problem is because of torque management pulling timing out during the whole dyno run since my torque stayed above 360# all the way to 4800rpm. Doesn't GM set the maximum torque values somewhere around 360-370#. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, they do...for the shifts. Torque management pulls timing during the shifts to help preserve the tranny. I've never seen or heard of torque reduction while in a certain gear....maybe if you get into the abuse mode though.

 

Thanks for the response guys.
BigTex, here is the answers to your questions:
Answer#1: My truck pulls strong all the way up to the shift points but looking at the dyno sheet peak hp is reached at 5000rpm & I shift at 5400rpm.

Answere#2: I wish I had autotap but I don't, hopefully I can get my brother to put my truck on his tech 2 scanner so I can look at the timing & kr during a wot run so I could see if there is a problem or not.

Answer#3: The first time I dynoed my truck & got 314hp my trucks a/f ratio was less than 10:1, the last time I dynoed it the wideband 02 machine was broke by a mustang that dynoed before me so I couldn't see if the a/f has improved or not.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2ksleeper:
<strong> Thanks for the response guys.
The first time I dynoed my truck & got 314hp my trucks a/f ratio was less than 7:1... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Did you type that right? 7:1, that is wayyyyy tooo rich, 12.3 is where you should be. you need some tuning with all those mods anyway, i suggest ls1edit or sending it off soon, there's a lot more power to be made if your a/f is that screwed up.

 

FarmTruc, I went and rechecked the dyno chart & what I posted was incorrect. The a/f ratio was 14/1 before he dumped the throttle, then it went to 11/1 for about 500rpm then is dropped off the chart which read down to 10/1. I dont believe it is running that rich right now but I will find out when I have to have it redynoed when they get the a/f meter fixed.

 

I try and keep mine at 12.3-7, that's for nat. aspir. I was running abou 11:1 at the track, i leaned out WOT and it went up to 12.3, i know there was more HP as a result because i keep overpowering my wheels. that's how i got my 105, once i have tracition i can get a little more consistent,

good luck

 

2ksleeper - Do this: Buy good set of used LS1 heads. Port them or polish them if you want, dont if you would rather not. With LS1 heads, you'll drop compression and make better boost. Lightnings run 8.5:1 compression, with LS1 heads you should be just under 9:1. This will let you safely up your boost without detonation. Plus, you can find LS1 heads (99+) for a little over $200. Then sell your take off 5.3 heads for upwards of $300. That extra will pay for gaskets and bolts. Do a cam at the same time if you want.

 

i have a set of ls1 heads for sale

 

BigTex, thanks for the suggestion about the heads, I will keep that in mind when my attention goes back to the motor. The next thing I am going to have to fix is my transmition, it is starting to slip. I also plan on tossing my crappy G80 before I do any more engine mods.