How many lbs of boost?
Are you boosted? Just asking. Talked to LE and he recommended no thicker than .040. But with .055, that would put me 10:47 which would be a lot better for my boost.....
Whats your turbo size?
I just went outside with the Micrometer and measured the Fel Pro Head gasket and it was .056 thick which is around Im guessing .048 or .049 compressed thickness. So I think it will be around 10:6 CR. So I know if a lot LT4's using 10lbs+ of boost I should be ok......
I just went outside with the Micrometer and measured the Fel Pro Head gasket and it was .056 thick which is around Im guessing .048 or .049 compressed thickness. So I think it will be around 10:6 CR. So I know if a lot LT4's using 10lbs+ of boost I should be ok......
Last edited by SwampWS6; Jan 13, 2014 at 01:09 PM.
if it makes you feel any better I ran a set of .055 gaskets on a turbo ls motor I did a while back....made 675 at the tire on pump gas and its still running strong with no issues......long as its a good mls gasket and the deck finishes are correct you are good to go!! 
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Verdad Gallardo Was .055 the compressed thickness? So I could use the .055 as my calculation in my CR? Only thing now is it was a LS and mine is a LT1.....LOL!!! How much difference would that make????
First If you plan on running decent boost, then choose a MLS gasket. Proper Head studs are needed. A certain LSA is meaning less unless you are comparing off the shelf cams from the same company with the same lobe profiles.
Second, Quench does matter in boosted engines as well as N/A. As tight as N/A not so much, but there are two sides to the boosted demon. At low speeds and low boost the motor needs more quench and Less at higher rpms/boost. So a Street engine should make you choose the former of the two.
I think that 10:1 is a great happy medium for a street boosted LTX. A proper sized intercooler is also going to be worth its weight in gold. A water/meth kit is sometimes a decent option but the meth adds fuel to the mix and needs to be accounted for in the tune or is just makes the AFR richer.
Also you need to account for the boost pressure on the valves. Extra boost on the intake side of the valve is working against the valve springs holding the valve to the seat. So the more boost you add to the system without changing springs will drop the Rpm that the springs will reliably control the valve to. But hey IDK anything...
Second, Quench does matter in boosted engines as well as N/A. As tight as N/A not so much, but there are two sides to the boosted demon. At low speeds and low boost the motor needs more quench and Less at higher rpms/boost. So a Street engine should make you choose the former of the two.
I think that 10:1 is a great happy medium for a street boosted LTX. A proper sized intercooler is also going to be worth its weight in gold. A water/meth kit is sometimes a decent option but the meth adds fuel to the mix and needs to be accounted for in the tune or is just makes the AFR richer.
Also you need to account for the boost pressure on the valves. Extra boost on the intake side of the valve is working against the valve springs holding the valve to the seat. So the more boost you add to the system without changing springs will drop the Rpm that the springs will reliably control the valve to. But hey IDK anything...
First If you plan on running decent boost, then choose a MLS gasket. Proper Head studs are needed. A certain LSA is meaning less unless you are comparing off the shelf cams from the same company with the same lobe profiles.
Second, Quench does matter in boosted engines as well as N/A. As tight as N/A not so much, but there are two sides to the boosted demon. At low speeds and low boost the motor needs more quench and Less at higher rpms/boost. So a Street engine should make you choose the former of the two.
I think that 10:1 is a great happy medium for a street boosted LTX. A proper sized intercooler is also going to be worth its weight in gold. A water/meth kit is sometimes a decent option but the meth adds fuel to the mix and needs to be accounted for in the tune or is just makes the AFR richer.
Also you need to account for the boost pressure on the valves. Extra boost on the intake side of the valve is working against the valve springs holding the valve to the seat. So the more boost you add to the system without changing springs will drop the Rpm that the springs will reliably control the valve to. But hey IDK anything...
Second, Quench does matter in boosted engines as well as N/A. As tight as N/A not so much, but there are two sides to the boosted demon. At low speeds and low boost the motor needs more quench and Less at higher rpms/boost. So a Street engine should make you choose the former of the two.
I think that 10:1 is a great happy medium for a street boosted LTX. A proper sized intercooler is also going to be worth its weight in gold. A water/meth kit is sometimes a decent option but the meth adds fuel to the mix and needs to be accounted for in the tune or is just makes the AFR richer.
Also you need to account for the boost pressure on the valves. Extra boost on the intake side of the valve is working against the valve springs holding the valve to the seat. So the more boost you add to the system without changing springs will drop the Rpm that the springs will reliably control the valve to. But hey IDK anything...
The cam will be a custom grind from LE to fit my current app............ Oh and if I use MLS HG, will I have to retorque the heads again after the first heat cycle?
I read your other thread.
IMO, sell your heads and get the 62cc 195 Trick Flow or the 65cc 195 AFR heads.
As a must, get a proper turbo for a 383. PT or the newer Tnetics 7875/7675 as a minimum. Not the TC series.
IMO, sell your heads and get the 62cc 195 Trick Flow or the 65cc 195 AFR heads.
As a must, get a proper turbo for a 383. PT or the newer Tnetics 7875/7675 as a minimum. Not the TC series.
Last edited by Purple Poncho; Jan 13, 2014 at 03:17 PM.
UUmmmmm..........If I could, I would. I do not have that type of money laying around. Like I said, this was not a Turbo build to begin with. So im just changing around a couple things to make it work...........That is why im asking so many questions. If I was doing a turbo build from the jump, I would know what to do with minor questioning. I was just trying to compensate weak areas for what I already have.............
I've said it before and I'll keep saying it. Take your heads off and get your chambers opened up. If your sig is correct and you have Lloyd TF 215 heads like you said then find out the current cc and have a porter expand them. 67cc is doable with those castings, there is a lot of meat on them.
Do you know the specs of your motor?
Piston dish cc
Deck clearance
Combustion chamber volume
and tell us your current CR and head gasket thickness/bore for reference
Do you know the specs of your motor?
Piston dish cc
Deck clearance
Combustion chamber volume
and tell us your current CR and head gasket thickness/bore for reference
-16
.001
55
Bore: 4.110 Thickness: .048
So my CR is 10:6
Point is, Im dealing with what I have without spending larger amounts of money. I know turbo builds cost large $$$. I know my C chamber is tight but that is not the issue im worried about. Not tryna be a dick or anything......
But if I had additional money I would get the heads reworked for that. I was just wanting to know my limits and trying not to surpass it. Im not building a 9 sec car, just something I can have fun with. My next build will be a LS or LT turbo build and I will do it the correct way with lowering my CR.......
This started as a N/A build.......This is not an optimal build for a turbo!
There are guys here in STL that have LT's and LT4's that has front/rear mount turbos running over 10lbs of boost with no meth injection, intercooler with 6K+ miles on the motor running stock CR and some with 11:1. Is it the best idea? No, but if I do it within reason especially with a forged bottom end, it should last long enough. Considering E85 or meth injection to help with longevity.
But with the things that I've changed to compensate with the power of the turbo, I don't see why it would work. I have some people's votes and some disagree. I just wanted to know my limits........ OP was how many lbs of boost? Not to rearrange my whole setup....
Boost numbers mean ****, all that means is you have a restrictive intake path.
T4 70mm Turbo
Garrett Internals:
Compressor:
70mm / 62 trim wheel
4" Inlet / 2.5" Outlet
Turbine:
.81 A/R
If that is your turbo specs, well, its gonna peak really early and especially with the higher CR.
Either save and do it right boosted, or do it right NA... just sayin'
T4 70mm Turbo
Garrett Internals:
Compressor:
70mm / 62 trim wheel
4" Inlet / 2.5" Outlet
Turbine:
.81 A/R
If that is your turbo specs, well, its gonna peak really early and especially with the higher CR.
Either save and do it right boosted, or do it right NA... just sayin'
Boost numbers mean ****, all that means is you have a restrictive intake path.
T4 70mm Turbo
Garrett Internals:
Compressor:
70mm / 62 trim wheel
4" Inlet / 2.5" Outlet
Turbine:
.81 A/R
If that is your turbo specs, well, its gonna peak really early and especially with the higher CR.
Either save and do it right boosted, or do it right NA... just sayin'
T4 70mm Turbo
Garrett Internals:
Compressor:
70mm / 62 trim wheel
4" Inlet / 2.5" Outlet
Turbine:
.81 A/R
If that is your turbo specs, well, its gonna peak really early and especially with the higher CR.
Either save and do it right boosted, or do it right NA... just sayin'
That being said, if you are dead set on this, build it up and get the tune dead on. Just make sure you get a quality wastegate and BOV, size them accordingly for later on.
A T4 flange is a huge selection for later on, IE my 7675 is a T4 but I have a .96 ar compared to your 70mm with an .80 ar.. so get all the bugs out with this iteration and then save up for a bigger T4 unit.
Or, risk your motor and get a cheapo ebay T4 unit. Their a few hundred bucks...
The exhaust housing on that turbo is whats going to hold you back.
That being said, if you are dead set on this, build it up and get the tune dead on. Just make sure you get a quality wastegate and BOV, size them accordingly for later on.
A T4 flange is a huge selection for later on, IE my 7675 is a T4 but I have a .96 ar compared to your 70mm with an .80 ar.. so get all the bugs out with this iteration and then save up for a bigger T4 unit.
Or, risk your motor and get a cheapo ebay T4 unit. Their a few hundred bucks...
That being said, if you are dead set on this, build it up and get the tune dead on. Just make sure you get a quality wastegate and BOV, size them accordingly for later on.
A T4 flange is a huge selection for later on, IE my 7675 is a T4 but I have a .96 ar compared to your 70mm with an .80 ar.. so get all the bugs out with this iteration and then save up for a bigger T4 unit.
Or, risk your motor and get a cheapo ebay T4 unit. Their a few hundred bucks...
Now the question is, Can I get the exhaust side ported? I will not buy an ebay turbo. To save myself headache (To many fail stories)..... I have a turbosmart wastegate and greddy BOV.