Which cam should I use for turbo?(dyno # update)
That's a big jump, I'd honestly shoot for a 92mm wheel with an automatic, a 83-87mm is my choice for a stick shift car.
Agreed on all points. I'm doing some mild testing with some good customers of mine that have agreed to it that concerns overlap and forced induction cams in general. Dyno and track results...should be very interesting information either way.
Thanks for the kind words Mike. I'm also with Jim, I do not like the TC series turbo's along with most Comp turbos. Just seem very mismatched to me.
Martin made some good points here. I do generally disagree with too much overlap equaling high rpm power drop off but with a TC76 it certainly isn't helping.
Somewhat along the same lines of thinking, I look at it like this.
How much power is the turbo capable of making and how much cam do you really need to efficiently max out the turbo?
In this case the cam is unnecessarily big for that turbocharger. I would guess that anything much bigger than low 220's at .050 would not realize any more max power.
A smaller cam that shifts NA power production lower in the rpm range will help response dramatically.
Having said all that, I still really do not like the TC series turbos.
Somewhat along the same lines of thinking, I look at it like this.
How much power is the turbo capable of making and how much cam do you really need to efficiently max out the turbo?
In this case the cam is unnecessarily big for that turbocharger. I would guess that anything much bigger than low 220's at .050 would not realize any more max power.
A smaller cam that shifts NA power production lower in the rpm range will help response dramatically.
Having said all that, I still really do not like the TC series turbos.
I did the same thing, If your looking for 800rwhp the Borg Warner 80mm with 83 or 87mm turbine is a good place to start. I'm not sure what they call it ST80, S483, S487 etc I'm not sure. There's some good choices, the above are just reference to the size you would need. Jose at Forced Induction has helped alot with helping me pick the right turbo for my combinations, I've learned alot from Martin at Tick on camshaft, compression and tuning from his threads. Lot's of knowledgable people on here.
The TC series is really suited to high powered 4 cyclinder motors.
The TC series is really suited to high powered 4 cyclinder motors.
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In his initial question he asked about switching over to stock cam short term. Would that stock cam with that turbo set up yield any benefits over his current cam? Would his power still stall at the upper end to the same degree?
Stock cam doesn't have optimum opening or closing events to make power past 5500-5800rpm just like it is now and would make less power in the mid range than this cam. It might make the same or just a touch more from idle-2000rpm.
Power would stall, just from different factors. This is why choosing a cam isn't as easy as looking on Speed Inc's. web site or Tick Performance's web site and choosing what cam you think is best because someone else ran one with good results. Always best to consult before buying, and by no means am I saying you or the OP did that. It's just always best to consult who you feel most comfortable spending your hard earned money with.
I feel like its pointless to throw my opinion out there when all the guru's have chimed in but ill do it anyway.
My cam, duration wise, is not much smaller than the OP's and actually has a 111 LSA with a higher intake lift (8degrees of overlap iirc). Car spools incredibly fast. I feel like with an auto it should spool almost instantly with a TC series turbo.
It definitely wont hurt to put a better cam in there but you may want to look into tune/stall like they mentioned too.
My cam, duration wise, is not much smaller than the OP's and actually has a 111 LSA with a higher intake lift (8degrees of overlap iirc). Car spools incredibly fast. I feel like with an auto it should spool almost instantly with a TC series turbo.
It definitely wont hurt to put a better cam in there but you may want to look into tune/stall like they mentioned too.
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IMO the TC series isn't really well suited to anything. Regardless of displacement this turbo will be the cause of more backpressure than necessary due to the undersized turbine.
Not sure why they even make a 78 as that's a step in the wrong direction.
I would bet that a TC70/F1 would be more efficient than a TC76/78 up until the point it was maxed out.
Not sure why they even make a 78 as that's a step in the wrong direction.
I would bet that a TC70/F1 would be more efficient than a TC76/78 up until the point it was maxed out.
I feel like its pointless to throw my opinion out there when all the guru's have chimed in but ill do it anyway.
My cam, duration wise, is not much smaller than the OP's and actually has a 111 LSA with a higher intake lift (8degrees of overlap iirc). Car spools incredibly fast. I feel like with an auto it should spool almost instantly with a TC series turbo.
It definitely wont hurt to put a better cam in there but you may want to look into tune/stall like they mentioned too.
My cam, duration wise, is not much smaller than the OP's and actually has a 111 LSA with a higher intake lift (8degrees of overlap iirc). Car spools incredibly fast. I feel like with an auto it should spool almost instantly with a TC series turbo.
It definitely wont hurt to put a better cam in there but you may want to look into tune/stall like they mentioned too.
With T56 turbo cars I like to mainly use 113-114LSA just for this reason, it makes more torque in the 5000-6000rpm range and really helps pull a T56 with it's wider gear ratio spread back into it's peak power band after a shift than using a wider LSA would. The overlap helps to broaden the torque curve and IMO helps boost recovery by adding to the drive pressure in the turbine housing.
Last edited by Sales@Tick; Nov 30, 2012 at 09:34 AM.
Here's what my car does with a 83mm and a 4L80E
390, etp heads, TU2 cam, 9" 3.50 gears
If I did it over I would go with a smaller cam.
https://ls1tech.com/forums/forced-in...dynograph.html
390, etp heads, TU2 cam, 9" 3.50 gears
If I did it over I would go with a smaller cam.
https://ls1tech.com/forums/forced-in...dynograph.html
Once again, the right amount or more than the right amount of overlap = fast spool-up.
With T56 turbo cars I like to mainly use 113-114LSA just for this reason, it makes more torque in the 5000-6000rpm range and really helps pull a T56 with it's wider gear ratio spread back into it's peak power band after a shift than using a wider LSA would. The overlap helps to broaden the torque curve and IMO helps boost recovery by adding to the drive pressure in the turbine housing.
With T56 turbo cars I like to mainly use 113-114LSA just for this reason, it makes more torque in the 5000-6000rpm range and really helps pull a T56 with it's wider gear ratio spread back into it's peak power band after a shift than using a wider LSA would. The overlap helps to broaden the torque curve and IMO helps boost recovery by adding to the drive pressure in the turbine housing.
It's combination specific for sure.
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Ok so I put my car on the dyno as it was and lets just say I did not expect numbers this low. Is this combo so mismatched I am making this low of power?
*pull made with unlocked converter 4l80e
*pull made with unlocked converter 4l80e
Last edited by Silver_TransAm; Dec 11, 2012 at 09:38 PM.
Wow, I wasn't expecting it to be that low, it really seems to be falling off hard after the torque peaks. FWIW that looks like a MD dyno print-out, but even with DJ correction it's high mid to high 400's.
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car feels faster than 431rwhp but I can feel the power taper off on the street.
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Bingo. The magic question. Boost drops from 14.6 back down to 11 ish between 4k and 6k. Could it be a little valve float?
Also, what size FMIC are you running? Could be restricting flow at higher RPMs. Maybe. Just thinking out loud....
Also, what size FMIC are you running? Could be restricting flow at higher RPMs. Maybe. Just thinking out loud....
Last edited by HRHohio; Dec 12, 2012 at 01:41 AM.
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This is on my buddies car. 6.0, TU1 cam, stock 317's, ls9 gaskets, ON3 76mm turbo, 80 lb inj running e85, 4l80e with 2.73 rear gears in the 10 bolt. Like it's stated at the bottom of the graph on 9psi he made 531/513 unlocked on a dynojet. Something doesn't sound like it's meshing with the rest of your combo. What boost controller are you using?
