Looking for a good / great cam for low end torque. i.e getting out of corners and up to speed. 2000 - 4800 rpm tq range is more important then 4800 to 6500. However, If I can have both even better.

Not a street car, so emmissions not a concern, but setting up road race; repeated 2000 to 6500 use, every 2 min for 20-50 min at a time

I have a set of PP LS6 heads from Lingfelter
http://www.lingenfelter.com/store/88958622.html

"The GM Performance Parts fully CNC ported aluminum LS6 cylinder heads provide excellent performance with an unbelievable price tag. These heads flow over 300 cfm at .550” lift and come fully assembled and ready to install with ZO6 lightweight valves and 02 ZO6 springs. This version #88958622 has 60.9 cc combustion chambers. You should check pushrod length and intake port alignment during installation."

Bottom end is '03 LS6, also have TPIS 90mm tb

Looking at a 12:1 and running 100 octane.

Currently have TPIS LTs, High-Flow cats and straight pipes. Most likely will change LTs and remove Cats to suit new heads and cam.

TIA
Tom

 

I have NO IDEA how the cam I have would respond to all that compression (as with the heads I'm looking at would bump me only to ~11.4:1 I believe), and I'm sure there are better choices with the parameters youlisted, but I have a nice torque curve with some great midrange punch (2k-4800 like you mentioned). Here is my graph, http://www.fquick.com/garages/viewga...ewimg&id=48122

HTH, good luck.

-J

 

Tom:

I'm running a 228/232 110+2 Custom Comp Cam on a 62cc head.

This might be to a little too much "DCR" on your setup, and the the PRC head intake runner size (200cc) favors low/mid end..but it might give you some ideas.

Good luck..WeathermanShawn.

 

Shawn What lift are you running?

Oh these heads are the Speed World GT heads.

I just dont want to run the SWGT cam of 239/251 570/570 106 LSA 2000-7000 rpms

 

Tom:

228/232 110 +2 .588/.595 (lift). XER Lobes..

 

218/224 .585/.585 110+3 is a trq. monster.

 

Sounds nice

I have a 228/232 112+4 .588 .595 on the shelf waiting to go in now...can't wait!!

 

if you are going to keep running 100 octane in it that 228/232 exr would be a sweet cam for that motor but if you ever step back down to 93 your dcr will be very high with 12:0 with the cam on a 110 +2 imo. i ran 11:7 scr,8:9 -9:0 dcr with a 228 xer lobe cam on a 112 +2 so that cam will be well over that. i had 57 cc heads so if you use a set of .040 cometics your scr may still not get you up to 12:0. have you done any scr calculations yet ?

 

232/236 and I made like 385 ft-lbs @ 3000 rpm's. 11.9 SCR and I think it is like 8.7 DCR on 93 octane if I remember right.

If you are road racing you shouldnt have to worry about low end TQ really anyway, you should be shifting to keep the rpm's out of the low area.

 

Not yet. That is why I want some cam options.

Not likley to go back to 93, too much of a power loss. Once these heads and cam go in, it will no longer be streetable ( cage and fire suppresion going in shortly)

I most likely will have two computers, one for 100 and above 80 degrees and ove temps in the 40s to 60s on 100 octane. Could reporgram one puter of 93 is an option, but I think there will be too much power loss.

I should clearify myself. I would like to run 12:1 or as close to as possible, which ever provides the best power options.

 

I can understand where you come from. However, using the low end tq is acctully quicker then shifting too much. Each shift is .5 sec difference, so down shifting and upshifting too much is a full second per lap. That full second is not possible to make up by staying in the RPM HP sweet zone or 4800 to 6500 rpms. There are many times or you just cant shift and the rpms drop into the 2500-3000 range, so need to optimise that use.

I have driven lots and lots of vettes with differnt cams and gears ratios,( MN12 and MN6 with 3.42, 3.73 and 4.10s and combinations of each) so I already have 1000 more like 10s of thousnad of track miles and 4 plus years on the track. Plus with too much shifting there are trans and oil temp issues.

Yes I have a trans cooler and accu-sump with oil cooler as well.

I have used some data aquistion equimpent on tracks I know very very well and put down some very respectable lap tims. Keeping the car in the higher RPM band did not produce lower lap times, but acctully slow lap times and more engine and trans abuse. For the most part a MN6 3rd and 4th gears with 3.42s on most tracks produce the lowest lap times. with the slowest lap times using MN12 with 4.10s Way too much shifting and overly high trans, diff and oil temps

The LS6 has lots of low end torque and high end HP. Too many guys opt of the High end HP and suffer out of corners.

There is one straight on a track I frequently use, VIR back straight. Coming out of Oak tree turn( very tight right hander about 45 mph) guys with MN12s and 4.10s use, 2nd 3th, 4th and 5th to get from 45 to 145 mph. I use 3rd and 4th to get from 45 to 152 mph. That is 2 less shifts ( full second ) and plus 7 mph more or about 100 feet futher.

I currently run just over 405 rwtq and 400 rwhp with stock LS6 heads, 224/224 525/ 525 112 lsa comp cam on a 4:1 mix of 93/100 octane
( I lost the cam card so dont rember the lobe)

I hoping to pick up 50-60 ft lbs of tq with these heads ( bigger intake valve and smaller chamber) and differnt cam.
The SWGT engines with light weight rotating assemblies and fast 90/90 with these same heads and the SWGT cam ( above) put out close to 550 fwhp

HP sells cars and equimpent, TQ wins races.
So we will see

Thanks guys for the help

Tom

 

I am not saying to optimize up high, but I cant imagine coming out of corners at 2k rpm. I know less shifting is better but your probably will have a hard time with a cam that you want to pull out at 2k with. I would think minimum of 3k at all times would be better. I could be wrong though.

 

Brad I think you are correct about needing to change my driving once the new heads and cam go in.

Just because I drive one way with current set up, does not mean it will be the same.

We tuned the car for optimal use of each gear. and will do so again with the new heads and cam

 

I'd consider a reverse split or single pattern and a cam design without advance ground in. I'd try to keep the overlap limited to 10* or less if you want such a wide range of power. Lots of overlap will kill power at 2000 rpm in a cam designed for a 6000 rpm peak, I'd think about opening the exhaust valve later than most big cams people on here are running and I'd try to keep intake valve opening on the later side. Something in the range of a 228/224 110 112 or 228/228 109 111 or 232/228 110 110 might be worth considering.

I don't have my DCR calculator handy, so I'm just eyeballing the specs to give you something new to add to the discussion.

 

The heads you're looking at have a 240ish CC intake runner, that does NOT = torque. I have used those very same heads in my last combo. If torque is your main concern all the while making some nice gains in the HP department I would look into the AFR 205 cc ,TFS 215cc or some PRC 200cc Terminator heads.

 

What's the DCR limit with 100 octane fuel?

 

I have a second set of heads which are the same but a 65 cc vs the 60.9. Bought both sets slightly used from a Grand AM engine builder for $2K. Which ever set of heads I deceid not to use I would most likley sell.

Some of the more popular heads ( which I will not name) have high failure rates on road course.

However, to achive the torque range I am looking for if I have to sell the two sets of heads I have and get something more applicable, then I will do that.

ANd do to costs to finishes convertion of my car to full race car a second engine is not an option for a year or 18 months


Thanks Ragtop some good looking numbers there.