Anyone use a summit turbo cam? Curious how good they are. I have a custom specked cam for when it was NA. Not sure how good will be with turbos. It’s 228 236, 595 613 112 +3

 

Lot of good info on Summit Racing cams, including with turbos, with a quick search. Your goals will determine the stage but they've got what you need. You can compare your existing cam to theirs and they have a cam calculator as well to play with.

 

Stg 2 with a 5.3 runs comfortable 9s in a 3600 lb car

 

any cam is a turbo cam

 

Only if you run them at baby back pressure ratios! Put a big "NA" cam with a typical 2:1 or worse BP ratio setup and suddenly that statement is BS. That RH fella runs some baby boost with wildly inflated numbers compared to what you'd see at the wheels on a standard setup.

 

Thanks. Never truely believed that statement, why I’m asking. Though I won’t be running any huge boost numbers. But would be nice to turn it up if I want too.

so what do you recommend?

 

Not exactly false, just has some guidelines Richard tends to not mention that apply to real world application. It's hard to suggest anything without a ton more info on the setup. Give us all the details and I'm sure you'll have plenty of suggestions. Generally not a night/day difference between most suggestions with similar valve events. But I'm sure we could get you close. I'm by no means a "cam guy". But I've played with quite a few so I have some general experience.

 

If you reach out to the guys at Summit or tag them on this post they'll chime in.
They claim to have done a ton of R&D developing these cams and I think for the average street/race hobby enthusiast they'll work just fine.
With that said if you're going through all the work to install a turbo charger on your car, I would certainly want a cam that would optimize the combination.
Smallwood Racing Developement
LJMS/BTR
Brute Speed
Summit
Can't go wrong with any of these.

 

the turbos are two CX GT35’s, 68ar. 5.3l. Summit forged rotating assembly 10:1 compression. 2600lb car. 6sp manual 4:11 gears.

 

What is the power goal? Fuel? Redline? intake? 1/8th? 1/4? Street?

 

street car. Hoping to run about 700hp-ish. Fuel mainly will be pump. But there is finally E85 available here which I may run. But heard it’s more like E70. Intake is an LS6. Redline maybe 7k

 

FWIW Difference between E85 And E50 is like .2 octane (not 2 but .2) E70 is a great blend and won't require as much from your fuel system at E85. I'd run it if its available would make hitting your goal very easy. I wish I knew my BP I run the same turbos on a 5.3 and just haven't had the time to setup the sensor to read BP yet. My 5.3 is around 8.9:1 with no IC an I made 560/600 whp on 11-12lbs. Figure I'm down a good 50whp from no IC, small cam, and the lack of compression. I run it on 19lbs now (about E60 fuel) and I'd say it easily makes 700whp. (auto trans though). That's with a relatively small GM hot cam as well.

Since it's a manual I'd want it to be snappy down low. Your goals are pretty mild and you won't be revving it that high. Something in the STG2 summit line would work well. But IMO a tighter LSA and shorter duration would work even better for a manual setup. I generally ignore response and low end with an auto, but I've driven a few turbo manual cars with sloppy STG2 cams and it wasn't great!

Something like the TSP stg 2 or 3 high lift cams on the optional tighter 110 LSA. Also ask them how far you can advance that cam when you install it and do so.

https://www.texas-speed.com/p-8558-t...-camshaft.aspx

 

I didn’t think you’d want that close of LSA. I figured you’d want like 114 for a turbo setup. But I can easily be wrong in my thinking. That link isn’t a turbo cam. They list a few 5.3 turbo cams.
https://www.texas-speed.com/p-8574-t...turbo-cam.aspx

 

That's just a generalization to overlap.

It depends on the amount of overlap. Since you aren't revving it very high and using a stock manifold, theres no reason for alot of duration IMO. By limiting the duration and tightening the LSA it makes for a much snappier engine which is huge with a manual car IMO. The TSP cam I posted has negative 3* of overlap at .050. It will still be very "boost friendly" and tolerant of back pressure

You have 8* of positive overlap in your current "NA" cam. The summit STG2 has 2* of positive overlap. So the cam I suggested with the tighter LSA is more "boost friendly" in terms of overlap than either of those and will give quite a bit more low end performance.

I believe you'll be fine back pressure wise, and likely the cam you have will work ok. But it won't be "snappy" down low like the cam I suggested. Which IMO is a big deal with a manual car. Its really a night/day difference in response. They even sound better IMO with a tight LSA. More raspy and mean. Will also have a more aggressive overlap. I'd run a 109 LSA on that TSP cam if it were on an option.... you might ask them.

 

Toss those 4.11's and put in some 3.55's or even 3.23's.
I ran 3.73's with my T56 and I think 3.55's would have been just a little bit better.
4.11's with a six speed and turbo is useless.

 

thanks for the info! Good explanation.

 

I agree. But with the .5:1 6th. It makes 6 useless. With 4:11 the gearing takes it to 330kmh. 3:55 would be better for sure.

 

Hello Gentlemen. How can we help? OP, the basic story on the Pro LS turbo cams is the run the same intake lobe and valve events as our N.A. cams and the exhaust opening point is often the same as well. Where they differ is we close the exhaust valve a bit earlier and soften the lobe just a bit. This reduction in overlap is needed to offset the increase in reversion seen with most single turbos with T4 hotsides and full length exhaust system. They are American made and extremely high quality in manufacture. Here's an article on that. Here is a little bit on how the stage 1-4 cams are designed in increments and around lifts required by factory rockers and common .600 beehive and .660 dual spring packs. Here's an article that goes into a little more detail on the truck and turbo cams. We also have another on specific valve events and how they affect performance. Turbo Cams don't have a lot of overlap of course so you're not going to get the idle of our N.A. cams, but then again you don't get melted down pistons etc. either . At your weight, manual trans etc. the Stage 3 is the one we'd lean toward. Either the 2 or 3 have been well past 1000whp though so if you are looking for a bit better spool, the 2 would be a little easier to bring on boost.

 

I sent you a message the other day on here! would love to hear back from you! Thanks

 

Hello, there are a couple of us that monitor but neither of us on the weekends (usually). I'll check out the PM box now. Thank you.