I am having a hard time deciding which route to go with my car between ecs, heartbeat and heads, or hci on my ls2 c6. I was wondering what kind of drivability to expect with this kit. Thank you in advance.

https://gwatneyperformance.com/produ...kage/#camshaft

 

I'd probably call and check with GPI on compatibility there. Not sure what the compatibility with those heads would on an LS2 vrs an LS3, I know ittl bolt up but the compression might not be favorable. I'm sure they can cater something a little more custom to your needs if you call and tell them your performance goals and tell them drivability is a must. I'm not a big fan of all in one packages like this. I'd rather talk to the reps and source exactly what I need. For reference though you can absolutely do a heads cam intake setup with great street manners. ECS or Heartbeat would net you much more power with better drivability though. Keep in mind you'll have to swap to an LS3 style intake if you run that kit as you'll no longer have a cathedral port.

 

What camshaft is GPI using? Some of their cams have higher lift than I'd be comfortable with. If that setup is capable of 550 rwhp, I'd suspect a cam big enough to have a pretty negative effect on drivability. For the kind of money that setup costs, you can make more power, have better manners, and save money with a centrifugal blower rig.

You wouldn't have to change heads or intake mani if you went with an A and A or ECS centrifugal rig. Good power available even using the stock cam. Stock cam = stock manners and fuel eco. If you don't mind spending a little more, a Heartbeat TVS blower along with stock LS3 heads is a sweet setup. I think Edelbrock makes a TVS blower that uses LS2 heads. With a TVS blower, you can have instant full boost even in the lower rpm ranges. No waiting for rpm to rise before feeling any power increase. A whole lot of fun on the streets.

I did a heads/cam build on an LS3 a few years back. It isn't near 550 rwhp (500 actually), but it does have perfect manners. Crappy manners are a deal killer for me.

 

Thank you for your feed back. I believe it to be a large cam something similar to their ss4 cam. They say in ad that it has great drivability and can drive to work, cross country, or track but idk I think it will definitely be some what radical is my guess. I am with you it has to drive good maybe not perfect but pretty close. I'm so torn on which way to go and have been for awhile. I'm concerned with centrifugal sc for heat issues and not feeling it until higher rps and just having more parts to fail but cost wise and hp per dollar it seems like best bet. I also am considering this route because car only jas 16k miles and not sure I wanna break into it yet..
heartbeat I like other then cost of sc is high then additional cost of heads too but I like that it seems to be reliable for long time. I am concerned with traction too as I don't want to be stuck with just drag tires..
heads cam interest me because of lower weight , less parts seems you can be just as fast with less power, less heat issues but what concernse is breaking into a hardly used motor,, and having poor driving manners.. I don't need them perfect but I don't want the car to be just a race car just a fast street machine I can drive anywhere.
I literally have researched this to death and have talked myself into each build and out. I'm currently doing an ls3 swap into my 69 camaro and may just do a Whipple on that and then go ecs or hci on corvette but idk I really like the heartbeat too for my goals. I wish I had just bought an ls3 vette it would be a little easier to justify the hb then.
edelbrock would be cost effective but I have read a lot of bad performance posts so I been leaning hb if I go pd.

 

The ss4 cam specs are these and I think the max 2 is a little bit bigger.
In./Ex. Duration236/252

In./Ex. Valve Lift
.646/.637
LSA113

ICL+4
The MAX Performance Camshaft is 2 deg larger on both lobes but is positioned 3 degrees later so the below the curve torque is likely a break-even comparatively speaking.

 

That would be a miserable street cam, I have a very similar spec'd cam sitting on my shelf. Spec'd by a supposedly big name LS guru that many worship, it does not have very many miles before I gave up. I tried, then had a few other tuners attempt to get some street manners, lesson learned is overlap is overlap regardless of engine size. It yours for free if you want it, I could never sell it to anyone.

The good news is a smaller cam will not give up power & dramatically improve it under the curve where you drive it. The limiting factor is the intake manifold, 6400rpm is it. The only thing I have found with a big cam is the ability to carry power beyond the 6400 area, it's flat but will rev. On the street I don't see any advantage.

I'm a strong believer in good cylinder heads, the cam is secondary. Poor heads, won't matter what your combination is, it will never be good. Your smaller motor I would probably stay with cathedral for air speed. There are some good choices.

I don't see 6spd or auto, doesn't matter. Your smaller engine would respond extremely well to a gear change doing a clutch @ the same time or torque converter. If you are a manual you will gain a more useable 6th gear. I rarely see gear changes discussed here, huge bang for buck with zero trade off.

I've never gone the FI direction, I enjoy the well built NA set ups. Maybe the clutter, weight I don't know, That new flat plan vette revving to 8500rpm is so sweet Ha!

 

Agree with CTD. 18 or 20 degrees of overlap doesn't equal any semblance of streetability. 640 lift cams are hard on the valvetrain too.

Here's a pretty well thought out LS2 build done with a very mild cam. Dyno Results - CorvetteForum - Chevrolet Corvette Forum Discussion I might have gone a little bigger on the camshaft, but nothing even remotely close to those GPI cams.

 

Thank you guys for your insight and advice I really do appreciate it. Out of the three options hb supercharger and ls3 heads, ecs sc, and hci with a smaller cam which build do you think would be ideal for a fast street machine that is street driven 99% and would have least amount of issues ? I have the money but can not decide which way to go. I've thought about a mamo hci build, a tf 225 with spinmonster cam build, hb with ls3 heads and blower cam, ecs pretty much by itself. Thank you.

 

Out of the three options the heartbeat is probably the most simple/maintenance free. PD blowers are pretty set it and forget it. Probably be a ton of fun on an otherwise stock motor.

 

Agree 100%. My previous C6 had the Heartbeat, full bolt ons, and a 224/234 116+2 custom cam. Perfect manners and 660+rwhp. Check fluids every other fill up. That was about the only reason to open the hood. Add flex fuel and an overdriven crank pulley and you can be over 750rwhp. There's no better blower for the streets than the Heartbeat....in my opinion.

I had a truck TVS2300 blower last over 250K miles before needing bearings. You'll wear everything around the blower out before the blower needs attention.

 

Thanks for your replies. I think I am going to go the heartbeat route even though cost wise it's kind of a hard pill to swallow but in the end for just a fast street car I think it may be my best rout plus I'm not looking for more than 600 rwhp. I'm looking at getting ls3 heads and cam from either livernois or gpi and adding hb to it.

 

At this point, I'd scrounge up a pair of used LS3 heads and send them to Tx Speed for CNC porting, competition valve job, milling as little or as much as you want, and setting up your valve springs. You get back a set of heads that you can't tell from brand new ones. Only they flow a hell of a lot better than the stockers. I don't know what the price is now, but I paid around $700 for the service. Hell of a lot of bang for your bucks. At a minimum, I'd want to have the heads cleaned up, do a valve job and a clean up mill on the heads. Just doesn't cost that much more to do the full meal deal that includes the CNC port work. Good flowing heads will lower your boost which will help with intake air temps. Cooler air going into the cylinders = more power. Magnuson says 1% more power for every 10 degrees lower the IAT's are. Some will tell you that ported LS3 heads will kill low end power. That may be when using a bigger cam. Not so with a mild blower cam and full boost coming in just past idle speed. Hell, Chevrolet uses square port heads on pickups.

Keeping the static CR up also helps a lot. You're going to lose CR if you just bolt stock LS3 heads on with a stock thickness .051 thick head gasket. There's no reason to have a low CR if you're never going over 10 or 12 psi. That's assuming you have 93 octane available. I'd get the heads milled 10 or 15 thou and use a Cometic .040 thick MLS head gasket.

I wouldn't fool with an "off the shelf" cam because you're not going to have an "off the shelf" build. Get Pat G to spec you a cam taking into account all of the changes you've made to your LS2. Some shelf cams might get you into PTV clearance issues with milled heads and a thinner head gasket. The $45 you pay to Pat G for his wisdom might be the best money you'll spend on your Vette.

 

If you're only looking for 600rwhp, call ECS and buy a supercharger kit and don't open the motor at all. If you want 700rwhp, that's a pulley change still with stock cam and heads too. A centri vs pos displacement s/c is a moot point. Even with a centri, you aren't going to have traction if you floor it on street tires.

 

Thank you guys for your info I really appreciate your advice. I think I'm going to lean towards sc and do hci. Like spun said the idea of not opening motor is appealing to me, but I worry about heat issues and reliability problems but at my desired power levels it may not be an issue and I might be over thinking it. But I also have read motorhead talk about how reliable and cool the hb blower is. But cost wise ecs probably makes most sense. Decisions lol.

 

I agree, as in WHAT driveability? I can speak with experience on my LS7s cam. I'm over 500whp with a 4L60E in my C5. Cam is a custom Futral by Cam Motion. It is 232°/250° duration, .603"/.608" lift, on a 112° LSA. 17° overlap. The tuner I use at Motor City Speed is VERY good, but you can only do so much with 17° overlap. I am happy with it, and can get around the mild bucking by adding just a bit more throttle, but I'm going to change it again. I previously had a cam in it I had bought for an LS1 Darton 427 motor, that had more lift due to the 1.8 rockers in the LS7. It was ground by Comp, and with the 1.8 rockers spec'd out at:
.638"/.646" lift, 238°/242° duration, on a 114° LSA, 12° overlap. Car made considerably more power, with better driveability.

 

There are no heat issues with an ECS kit especially in Detroit. I ran my s/c from them for 7 years and never was there an s/c related issue. Driveability is 100% stock unless you run street tires in the rain with 650rwhp and have a lead foot. That's where my screen name came from.

As far as cam driveability, it's simple, the less overlap, the better it drives.

 

I'm going to go ahead and go the ECS route, I think it makes the most sense for what I'm looking to do and it's more cost effective for me. I will put a pd blower and cam in my 69 camaro I'm doing an ls swap in. Thanks for the advice.
one last question in regards to putting centri kit on my car. Would it make sense to have heads worked at say TEA and add a blower cam to essentially make same 600 rwhp but at less boost? Is there a benefit at this level for this at the additional expense?

 

That is a bit larger than an SS4 NFC. I had an SS4 in my SS sedan. It required DEEP rear gears (3.90s) and a loose converter to make the most of it (4600/4700 stall in a 6L80E) It was NOT street friendly! I tuned it myself and it required ALOT of time to get it to run well. Idle tuning took the most time as the GM adaptives were far too sensitive for a cam that only pulled 9.5"-10" of idle vacuum and when I ran it open loop it would wind up hunting and oscillating at idle. Not fun at stop lights! I never dynoed it but it ran STRONG upstairs, I'd say it was making at least 525 at the wheels--I had the trans shifting at 7400 with a 7600 limiter. To be safe I went with Cam Motion springs that once shimmed to within 0.060" of coil bind had something like 200 lbs on the seat and 500 lbs open. I went with Cadillac Racing lifters and moderate pushrods (3/8" x .135" wall) I don't care what anyone says, running stock rockers past about .620" lift is murder on the valve guides as the rocker pulls and pushes the valve as there is a ton of friction under lift with stock rockers. I switched to Comp aluminum body roller tip
rockers and it seemed to rev easier. However, they ate fatter/taller and necessitated 3/8" tall valve cover spacers

Basically, I think a package like that while great for power and fun on a racetrack or drag strip is TERRIBLE for driving around! Even with cats you will STILL get fuel smell at idle because cams like that have 75 degrees plus of overlap (at zero lift) and the air/fuel charge gets pushed right out the exhaust at low engine speeds! My SS4 didn't really come on cam until 4000 rpm, which is why you NEED the loose converter, and deep gears. And if you a manual, you NEED a higher (numerically) rear end ratio--otherwise the car might wind up being slower. Cams like this look great on paper when they make 550 whp but there is a reason auto manufacturers don't use them from the factory!

 

What displacement was this in? What heads?

 

LS3 6.2
GMPP CNC ported LS3 heads
1 7/8" Kooks headers, sans cats
90mm Katech ported TB
Holley Sniper intake manifold