cam grunt
Thread Starter
Instructor
Joined: Sep 2004
Posts: 210
Likes: 0
From: peoria il
cam grunt
at what duration does the cam sound really turn into the muscle car sound. i have a 91 and i am putting a 383 with afr 195 heads and with tpis 1 3/4 headers and removing the 2 front pre-cats and i have magnaflow catback. one cam has a duration of 236/240, one is 222/222 and the other is 228/230. i want it to be fast but i don't want someone to hear it and know its fast. which cam is the best thanks......jeff
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
The 236/240 or 228/230. But with the 383 I would go with the 236/240 . I have a 236/236 and it really depends on how loud your exhaust is and weather its a hydraulic roller cam or a solid roller. With a quieter exhaust on mine and the idle at 900rpm I dont think anyone would have a clue to how fast my car really is.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
Also the compression of your engine has alot to do with the sound also. So does the LSA(lobe seaperation angle) on the cam. 106-108LSA lopey idle very rough, 112-114 smother idle more engine vacuum. We will need more engine specs and cam specs...
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Lope comes from valve overlap and also depends on CID. Larger displacement can stand more overlap.
You should be ok with 228/230 duration if it has 110-112 LSA on a 383; maybe even up to 236/240 duration.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
If you're asking which one would have the smoothest idle, the 222/222 would be it, assuming the lobe separation angle is the same on all three cams
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by rugby!
at what duration does the cam sound really turn into the muscle car sound. i have a 91 and i am putting a 383 with afr 195 heads and with tpis 1 3/4 headers and removing the 2 front pre-cats and i have magnaflow catback. one cam has a duration of 236/240, one is 222/222 and the other is 228/230. i want it to be fast but i don't want someone to hear it and know its fast. which cam is the best thanks......jeff
And not to mention that the more radical the cam the more difficult the tuning will be for the EFI system. I noticed that you have a 91 car which means you have a speed density fuel strategy, this system is not near as forgiving as a MAF control strategy. Tuning with a large cam can be difficult. Also with the 236 cam you will lose some low speed manners, meaning cam surge in city driving at lower speeds. The larger 236 cam is close to that of the GM 847 cam which is a 234/242 on a 112 LSA. I can tell you that the 847 cam has a noticable amount of cam surge even in a LT1 MAF car. My suggestion is a cam around 224/230 on a 112 which will offer better drivability than the larger cam.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
We were able to tune all of the cam surge out of my car(91 speed density) and my cam has a 110lsa. But in the begining before the fine tuning, it was there. It really depends on what you want and what you can live with and how fast you want to go. I agree that the 224/230 on a 112 will be a better driver. Right now I am looking at going to a 254/260@50 on a 112lsa, but mine is not a daily driver and I can live with all the little quarks of a big cam.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by chriswtx
We were able to tune all of the cam surge out of my car(91 speed density) and my cam has a 110lsa. But in the begining before the fine tuning, it was there. It really depends on what you want and what you can live with and how fast you want to go. I agree that the 224/230 on a 112 will be a better driver. Right now I am looking at going to a 254/260@50 on a 112lsa, but mine is not a daily driver and I can live with all the little quarks of a big cam.
I agree it can be done. He just needs to find a competent tuner with a good load bearing dyno. With that tool a good tuner can do a good job tuning it in. It just takes a bit of time to get a good tune on a SD strategy car.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
Yeah, it took us 3 different nights and a total of 26dyno runs to get it perfect. I dont think the tunnelram helped much either....Well of those 26 runs, 10 or so were us just playing with timing curves and fuel mixtures to see if we could squeeze any more HP out of it. 
