Turbo cam question

-
B

bblock383

Well-Known Member
Joined
Jun 25, 2011
Messages
105
Reaction score
0
Location
missouri
Hi all

I had a question on what lsa a turbo cam should be on. I recently had compcams recommend using the 244 I believe cam but have it custom ground on 112 lsa. Is this right? I was thinking it needed to be lower like 108 or 110? I don't know alot about forced induction cams. Anyone have a suggestion? Thanks
 
call and ask Brian of IMM engines in Indio, CA or Hughes
 
Usually 110 or more is recommended with a Turbo motor. The higher the LSA # the less you will hear the cam. I went with a 240@50 .634 lift ground on a 110 LSA, Brian at IMM chose my cam, I told him I still want to hear it lope like a muscle car.
 
Hmm so should I maybe have it ground higher than 112? Its for a slant 6 so its not gonna sound like a muscle car anyway. Would a higher lsa make more power?
 
bblock383 said:
Hmm so should I maybe have it ground higher than 112? Its for a slant 6 so its not gonna sound like a muscle car anyway. Would a higher lsa make more power?
Click to expand...

All depends on the combo, there are a few guys here that have pretty hot runnin 6's. I would probably use their recipe that is proven. I am sure they will chime in.
 
well bill is the guy here for boost 6... also turbo toad..

but you'll be amazed how a hot slant sounds...

[ame="http://www.youtube.com/watch?v=PZstyQMWmWU&feature=related"]YouTube - ‪6k shift‬‏[/ame]
 
I'm running a organ camshaft regrind #791 is the grind number it 483 on the intake and 486 lift on the exhaust with a LSA at 114
I'm just putting the final touches on the TURBO TOAD I've had to work ungodly amount of hours the last two weeks so the toad is only getting minimum amounts of my time!

I'm new to boost as well and I patterned my build from guys like Shaker223 and turbovaliant66 and Bill Dedmen
Check out my link on FABO it has my complete build documented also there are a ton of
Pics on the Photobucket link

Good luck oh it was around a 100 bucks for the regrind

Aaron
 
bblock383 said:
Well anyone else want to chime in? :)
Click to expand...

Are you wanting specs for a cam for a turbocharged slant six?

I never did get a solid idea that that was the engine you were interested in, but maybe I missed something (very likely.)

My experience is that I have none (never had a slant 6 running with a turbo,) but I read a lot on here, and the guys who actually KNOW from experience, (Tom Wolfe, Charrlie, and Ryan Peterson,) seem to recommend something like this:

Max lift, .484" (because that's about all you can buy,) duration, 220/220 degrees at .050" lift, and a cam ground with 116 degrees of lobe separation.

People seem to have good results with those specs.

Please correct me if I'm wrong, guys.

Hope this helps!!!
 
Ok here's what im trying to do here. I want a fun lil street car. Weirdly enough its hard to get advice on it because most people running turbo slants are drag cars basically running lots of boost and lots of money spent. I don't plan to run anymore than what this wastegate runs which is about 12 lbs from a stock Gn turbo. Probably will only run 8-10it n that's the it. Trying to do it on a budget like Wayne did in his article on slantsix.org. So im not doin anything big or trying to run 10s. 14s n 13s would be just fine. I am having some issues with with how to mount the turbo in a 66 cuda with power steering. Anyway hopefully this gives everyone an idea what im trying to a bigger accomplish.
 
bblock383 said:
Ok here's what im trying to do here. I want a fun lil street car. Weirdly enough its hard to get advice on it because most people running turbo slants are drag cars basically running lots of boost and lots of money spent. I don't plan to run anymore than what this wastegate runs which is about 12 lbs from a stock Gn turbo. Probably will only run 8-10it n that's the it. Trying to do it on a budget like Wayne did in his article on slantsix.org. So im not doin anything big or trying to run 10s. 14s n 13s would be just fine. I am having some issues with with how to mount the turbo in a 66 cuda with power steering. Anyway hopefully this gives everyone an idea what im trying to a bigger accomplish.
Click to expand...

I keep saying this, but only because I am SO impressed with the times, but Tom Wolfe (Shaker 223 on FABO,) in his initial effort, went to the junkyard and bought a used Buick G/N turbo and installed it (on the stock, cast iron, /6 exhaust manifold) and with no other changes (he did have a 2-bbl carb,) ran 12.95 @ 104 mph, with that stock engine.

So, I can't imagine your car would be much slower than that (this car of Tom's was a stock weight [about 3,300#] 1970 Dart 2-door hardtop.)

He did manage to get 21 pounds of boost out of that setup, which probably accounts for the strong performance.

Good luck; A stock 340 motor in an a body would have a tough time hanging with a car like that... and, it's so much cheaper...
 
Stock cams can make for good turbo cams.. Although I had an aftermarket GN turbo, the stock cam ended up going 11.77@117 mph. The car weighed about 3,500lbs as I had to add weight to get it to hook.

To answer your question, the stock cam is a good balance and will not comprimise anything in terms of perofrmance or streetability.
 
Shaker do you think the compcams cam on 112 lsa would perform better than the stock cam? I personally wouldn't mind having the slant sound good at idle so goin to a lower lsa would help that according to a previous poster but would it affect the performance?
 
The wider LSA kills the "sound" of a cam. My cam has a 114lsa and about 225 duration @50 and .475" lift and sounds stock.
 
So then the lsa doesn't affect performance? Y do people say with forced induction you need a wider lsa? Surely it can't be just to quiet the sound down?
 
bblock383 said:
So then the lsa doesn't affect performance? Y do people say with forced induction you need a wider lsa? Surely it can't be just to quiet the sound down?
Click to expand...

Just my opinion, but it seems to me that closer lobe centers which would result in greater overlap for any given duration, might allow boost to be blown out the exhaust while both valves are open, particulary undesirable on turbo motors.

I think THAT is the reason for wide lobe center angles (114 and up.)

Just my 2 cents...
 
So then the more lsa you have the more boost you'll keep in the cylinders which would make more power so then maybe I should go higher in lsa than 112?
 
bblock383 said:
So then the more lsa you have the more boost you'll keep in the cylinders which would make more power so then maybe I should go higher in lsa than 112?
Click to expand...


I think it de[ends on your setup. Ken Duttweiler opined in a recent article in Car Craft ( or, was it Hot Rod?) that the latest generation of ball bearing turbos don't benefit from that wider lobe separation, so that changes everything...

Our turbo is a conventional, old-school model, so we're going with 115. That was the thinking when it was built 4 or 5 years ago.
 
Has anyone had to modify their valve seats to use a larger cam? The machine shop I had clean up my head said to use a bigger than stock cam I had to have the valve seats or some such ridiculous thing done before I could use it. I've built several engines with larger than stock cams and I've never had to have this done. Anyone know anything about this?
 
Depending on what year your head is u may want to have hardened seats put in on the exhaust side I did mine on my 68 head but its my understanding that with the stock rods and piston there is plenty of room for piston to valve clearance
 
srixon4406 said:
Depending on what year your head is u may want to have hardened seats put in on the exhaust side I did mine on my 68 head but its my understanding that with the stock rods and piston there is plenty of room for piston to valve clearance
Click to expand...

yea any head older than 73 needs to have hardened seats installed on the exh...

and with the piston .150 or more in the hole i wouldn't worry about it
 
Actually guys im not talking about changing to hardened seats. Im talking about having to have the seats modified to run a bigger cam than stock. Not about modifying the seats to run modern gasoline. Misunderstanding I think. Kid I think you were on the right track at the end of your post. I don't know if they think the pistons will hit the valves like lid said ie what. The .440 cam from compcams should not be near big enough to do that. I've built v8s with over 9:1 a .500 lift and I've never had to have the guides modified in anyway. They must think the slant has 10:1 comp and im using a .600 or bigger lift cam. I have no idea just wanted to know if anyone has had to do this?
 
bblock383 said:
Actually guys im not talking about changing to hardened seats. Im talking about having to have the seats modified to run a bigger cam than stock. Not about modifying the seats to run modern gasoline. Misunderstanding I think. Kid I think you were on the right track at the end of your post. I don't know if they think the pistons will hit the valves like lid said ie what. The .440 cam from compcams should not be near big enough to do that. I've built v8s with over 9:1 a .500 lift and I've never had to have the guides modified in anyway. They must think the slant has 10:1 comp and im using a .600 or bigger lift cam. I have no idea just wanted to know if anyone has had to do this?
Click to expand...

well to give you an idea im running a flat top .157 in the hole (.030 off the block) and 44cc chambers (.113 off the head) so 10:1

then im running a .475 valve lift cam, 246 @ .050... with boost your not gonna be any where near than big...

BUT

you need to have them change the exhaust seats or you WILL sink a valve due to the extra heat you'll be building with boost...

and you dont modify the valve seats to run more lift lol, sometimes you have to cut the "spring seat" to allow for a proper installed height and sometimes cut the guide down so the retainer will not hit...
 
Well kid do you think ill have to make any mods at all? I can't imagine having to do any of that with only. 440 lift n stock compression. Also can you elaborate more on having to change the exhaust seats for boost? Do you mean that just new seats need to be put in?
if that's the case then that's already gonna happen with the head rebuild. I plan to do a few things to keep the hot spots down to help with detonation.
 
You must log in or register to reply here.
-

Back
Top