Recommendation on a cam change
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
Recommendation on a cam change
The combo is a street/strip 85; 3400+lbs. The engine is a fuel injected 10.5:1 406 with a super vic and brodix M2 T1s thru a full somewhat restrictive exhaust (stock LT1). Drivetrain is a 2800 stall thru a 700R to 3.45 gears and 28 inch tires.
The current cam is a 246/246 112LSA solid roller with .610 lift installed 7 deg advanced.
I'm working with a professional grade engine simulator, which seems to like a smaller cam. Interestingly, it shows a 235/235 112LSA installed straight up with less lift making significantly more HP than the larger 246/246. I'm a little confused by this. I know advancing the current cam is limiting the HP, but even if i assume it straight up, it only makes slightly more HP at a higher rpm than the 235 BUT at the expense of the low end. Given my weight, converter & gearing, it's important to maintain good low end torque and the 235 looks like the clear winner based on avg HP & torque from 3000 to 6500 rpms.
What do you guys think? Is it worth swapping to a smaller cam (235 vs 246). The simulator shows a gain of almost 30 hp & Tq. Is that possible?
The current cam is a 246/246 112LSA solid roller with .610 lift installed 7 deg advanced.
I'm working with a professional grade engine simulator, which seems to like a smaller cam. Interestingly, it shows a 235/235 112LSA installed straight up with less lift making significantly more HP than the larger 246/246. I'm a little confused by this. I know advancing the current cam is limiting the HP, but even if i assume it straight up, it only makes slightly more HP at a higher rpm than the 235 BUT at the expense of the low end. Given my weight, converter & gearing, it's important to maintain good low end torque and the 235 looks like the clear winner based on avg HP & torque from 3000 to 6500 rpms.
What do you guys think? Is it worth swapping to a smaller cam (235 vs 246). The simulator shows a gain of almost 30 hp & Tq. Is that possible?
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
What are the flow numbers on the heads ?
If flow numbers are great like they are supposed to be on those heads then I do not see why you would make more power with smaller cam try a 110deg Comp Cams solid roller with the same duration and lift like the XR286R and see what you get.
If flow numbers are great like they are supposed to be on those heads then I do not see why you would make more power with smaller cam try a 110deg Comp Cams solid roller with the same duration and lift like the XR286R and see what you get.
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
head flow as follows:
.2 150
.3 219
.4 263
.5 291
.6 294
.7 296
The sim doesn't show any significant difference between the 112 LSA and a 110 on the 246 cam. And given the restrictive exhaust, i dont think tightening the LSA would be a good idea.
.2 150
.3 219
.4 263
.5 291
.6 294
.7 296
The sim doesn't show any significant difference between the 112 LSA and a 110 on the 246 cam. And given the restrictive exhaust, i dont think tightening the LSA would be a good idea.
Last edited by ralph; Dec 2, 2004 at 10:04 PM.
