Cam for blown LS1

[streetk14]

I'm trying to find the right cam for my LS1 project. It is going in my '68 camaro with a T56 and 3.89 gears. My goal is 500 RWHP and I am going to keep the max RPM to 6500. here is my combination:

2002 LS1 (low mileage)
Intercooled Magnachager @ 7-8 psi w/ 90mm inlet upgrade
Ported LQ9 heads from Patriot Performance (aprox. 9.5:1 compression)
Stainless works 1 3/4" longtube headers
Dual 3" exhaust




I am looking to break the 500 RWHP mark, but also want to keep driveability and vacuum levels in check. At the same time, I'd like to have a bit of a musclecar lope at idle. So I guess I'm looking for a good compromise. There are some stealth cams out there that are supposed to work great with blowers. I have heard good things about the GT2-3 cam from Lingenfelter (207/220, .571/.578 & 118 LSA), but am worried it is going to have a very smooth idle. Others have said to look for something around 224/228 w/ a 114 LSA. The car is not a daily driver, more of a weekend fun car that I will take to the track on occasion. What should I do?

-Andy

[WS6]

The GT2 will be smooth running but perform well. Brian at magnacharger has a 5.3 running the GT2 with a magnacharger on his truck. He's making 500rwhp with that simple of a setup.

A 224/228 would do well for you also and have a noticable yet subtle lope.

See if Tony aka nineball replies to this about his old 69 camaro, if not PM him. I believe he was running a 230/233 cam or something close with his setup. Actually find a post of his and his website with all the info is listed in his signature.

Your goal is easy. I would consider dropping back down to 2-1/2 or 2-3/4 exhaust to help build some back pressure which will help keep the boost up as well.

[streetk14]

My goal seems to be well within reach with the GT2 cam, but I am worried that I will be disapointed with the sound. It is good to know there are guys making good power with such a mild cam.

I did pm Tony a while back. He had a 230/230 cam in his '69, which might be more than I want. I questioned him about the single pattern profile, and was told that longer exhaust duration is not needed when you have good headers & exhaust. I always thought blown motors liked split duration cams, but I have to say that it seemed to work well for him.

As far as exhaust goes, I will be building a new system. I had a 2.5" X-pipe system on the car before, but thought a 3" system would be better for the 600 hp that I should be making. If a 2.5" system will work better, that's great. The smaller system will keep the noise down and be easier to package under the car.

Idle sound aside, what do you think will perform the best? The GT2 cam seems like it would have stock manners , and great low end power. It is also supposed to have a very broad powerband. Do you think I would gain anything by switching from the GT2 to a 224/228 114 LSA cam?

[WS6]

You will gain mainly top end by switching to a 224/228 over the GT2. Remember though, the magnacharger makes all its power in the low to midrange mainly. It's not like a pro-chrager that doesn't start making power until 3,500. The 230/230 in a LS I personally don't like. I am conservative on what I put up with though idle wise. You will have a lope with the 224/228 cam. Personally, I would be interested in the broadest powerband versus which sounds better, especially with a street car. Cause honestly, the idle may sound wicked, but I prefer the blower sound at WOT to any idle lope a stock cube LS engine can produce.

[streetk14]

Can't I have blower whine AND a nice idle?

Would there be a noticable loss of low-end torque to go along with the gain in high rpm power with the 224/228? I am looking for a broad powerband, and with that said the GT2 cam is probably a better choice for the street. It will probably make better use of the magnacharger's low-end boost.

My old small block had a 242/248 hydraulic roller, and the idle sounded really mean. It was a chore to drive sometimes, and I had to run manual brakes. That is what I'm used to and is why I am having a hard time buying a "stock-sounding" cam. On the other hand, 500 RWHP and a mild idle will make one hell of a sleeper. What to do, what to do........

[WS6]

Well the thing to remember is that on street tires the blower will make more torque than you can handle down low. So loosing a little down low to gain some power on the top end may feel different but it should not hurt when at the drag strip or a long straight stretch of road. I personally think you'd be fine and enjoy the 224/228 cam. As for the 500rwhp mark I you'll get close if not over it. Either way it's an arbitraury number and you wouldn't be able to tell if you were over it or not from driving the car.

[Nine Ball]

dual 2.5 exhaust, I'd go 228/232 114
dual 3.0 exhaust, I'd go 228/228 114

The 230/230 was fine in my car, did the 4K mile round trip on Power Tour with it, no drivability issues at all. It was a weekend warrior musclecar, not a daily driver. I wanted a more aggressive cam in that car. Your 90mm t-body on the Magna will flow much better than my 78mm one did, so you might be able to use that 230/230 better. Might even hit 550 rwhp.

[streetk14]

dual 2.5 exhaust, I'd go 228/232 114
dual 3.0 exhaust, I'd go 228/228 114

The 230/230 was fine in my car, did the 4K mile round trip on Power Tour with it, no drivability issues at all. It was a weekend warrior musclecar, not a daily driver. I wanted a more aggressive cam in that car. Your 90mm t-body on the Magna will flow much better than my 78mm one did, so you might be able to use that 230/230 better. Might even hit 550 rwhp.

550 rwhp would be a very nice suprise

My car is also a weekend musclecar, so idle and fuel economy aren't major concerns.

Did you have any issues with your power brakes, Tony? I have a 9" dual diaphram booster that I will be using. I was going to run a hydro-boost, but decided a simpler approach was better for me.

One more thing I am concerned about with a larger cam is highway cruising in 6th gear. How well did your car cruise in 6th at 65-70 mph? My car has 3.89 gears and with 315/35/17 tires I will be doing 65 mph @ 1700 rpm and 70 mph @ 1800 rpm. Carbureted motors don't like being loaded like this, but I'm not sure how this motor will work.

I need to hurry up and make a decision so I can get this thing into my car. I haven't driven it in 6 months and it's killing me. Thanks for the help guys.

-Andy

[SLED28]

A cam in the 225-235 will have a little lope and still drive good. I would do a reverse split for boost in the LS1

[streetk14]

A cam in the 225-235 will have a little lope and still drive good. I would do a reverse split for boost in the LS1

Isn't that more for turbo applications? I always thought the exhaust flow needed help to move the extra air that is being forced in on the intake side. Some guys have said a single-pattern cam works well, but this is the first I have heard of using a reverse-split. Any reason in particular this a better route?
-Andy

[SLED28]

Yes you are right, I was talking about turbo boost. Sorry guys

[Nine Ball]

Howdy SLED!

Andy, LS1 engines drive nothing like junky carb'd engines

even with larger cams, they seem to drive okay as low as 1500 rpm. The cams I suggested would be 'medium' sized cams for a stock cube LS1. I had 3.73s and it had no problem cruising in 6th gear at lower rpm. No problems with the brakes working either. I had the SSBC master, not sure what size it was.

If you ever need to reach me, Tony @ LS1TECH.com (without spaces)

Tony

[SLED28]

Yo Nine Ball! Whats up!

[streetk14]

How about this: 226/230 .575/.595 114LSA

I have not made up my mind for exhaust. I think a 3" system is a better choice for performance, and I could use it at the strip without hurting power much if any. At the same time, the 2.5" system should be easier to deal with on the street. Decisions, decisions......

[WS6]

That cam with the 2.5" system would work well. Use 1-3/4" primary tube headers.

On a side note I just finished a TSP 228/228 114 cam in a 98 auto SS. Has a nice mix of sound and idle smoothness. Still playing with the tuning but the idle should work perfectly fine around 850-900 in nuetral and 750-800 in gear. Power band is nice with little low end loss. The 3200 TC makes up for that anyway. No problems with power brakes or anything else and you won't see any problems until you get to a large cam.