Mid-low 10s
- Thread starter vacuum 6
- Start date
SouthernCal GN
I come in peace....AK AK
- Joined
- Mar 18, 2004
Depends on your combo and build- you could bolt on a bigger turbo and push the snot out of it with stock heads/cam/etc.. or build the motor to flow better, and get your goals comfortably.
It may just be me, but I wouldnt feel all that comfortable going mid to low 10s with only 009s, even with alky 
.
As for a turbo, I know the next one I purchase will be the GT6776 with the S cover. That should take you deep enough into the 10s and work OK with your small stall.
.As for a turbo, I know the next one I purchase will be the GT6776 with the S cover. That should take you deep enough into the 10s and work OK with your small stall.
SouthernCal GN
I come in peace....AK AK
- Joined
- Mar 18, 2004
Agree on the 66, or the 6776. I think the problem will be fueling- you are gonna have to push those 009s to the max, even with alky.
Chris McDade
Active Member
- Joined
- Jul 13, 2001
Can you run low 10's on a 12" 2800 stall? I'd be willing to say NO!!!!!
Get a 9" Art Carr Non luck up 3200 stall and never look back. It's as streetable as the stock one.
Get a 9" Art Carr Non luck up 3200 stall and never look back. It's as streetable as the stock one.
Underboost
Mr. Dull
- Joined
- Oct 4, 2005
I'm running a PTE-70GTQ w/85. housing Non BB, 3500stall, and 72lb Motrons. Stock fuel lines with Red Armstrong Dbl pump system in the tank. Works great with Stock Ported Irons & Eric's chip.
vacuum 6
Well-Known Member
- Joined
- Jan 6, 2006
Thanks guys for al the 411. Just to clearify I never said I was going to run mid-low 10s with a 2800 stall and 009. Again I'm looking for a turbo that has the power to take the car to mid-low 10s. I would like to only upgrade the turbo one more time.:smile: Also if I need more injector, 60s here I come.
Underboost
Mr. Dull
- Joined
- Oct 4, 2005
I had a pt-67 p-trim with 60's and a 9'' 2800 stall, 373 gears with a Len Freeman built 200 and it was mid 10's all day long great street turbo also. The M/T ET Streets hated the power.
- Joined
- May 26, 2001
Here's my thoughts for a 3-bolt turbo for low 10s.
TSM legal, 235 - 248 CI built to handle the power motor, 3400-3500 stall converter, 72# - 84# injectors, pick your poison on the engine management system, good external pump or at a minimum double pumpers.........
PT7080RH aka PT70 GT-Q dual ball bearing with a .85 A/R 3-bolt Buick turbine housing. It will support up to 850 flywheel hp when maxed out.
Don't care about class racing, 248 - 274 CI motor, 84# injectors and again your choice of engine management system, external fuel pump only.........
PT7480RH aka PT74 GT-Q dual ball bearing with a .85 A/R 3-bolt Buick turbine housing. It will support up to 925 flywheel hp when maxed out. On this type of motor, this turbo will spool very fast with a 3600 stall converter and will easily make enough power for 10 flat ETs at mid 20s boost levels. You won't have to upgrade the turbo unless you change your goals to wanting to run low 9's to high 8's.
On a full weight car (3600 - 3650#) you need to make around 750 hp to the tires to run 10.00s @ 135 - 136. Obviously, the bigger the CI of the motor and the more flywheel hp that the turbo can support, the easier it's going to be to make the required power. Meaning, you wouldn't want to put a turbo that will just barely make the required power, just to barely run a time/mph. If I were building a 248 CI low 10 second combo and didn't care about racing any class, I would choose a PT7480RH myself. Spool up between the 70 and 74 with dual ball bearing and 3-bolt style housings would be very similar. Probably within 500 rpms. Only difference is the size and weight of the compressor wheel.
Hope some of this helps.
Patrick
TSM legal, 235 - 248 CI built to handle the power motor, 3400-3500 stall converter, 72# - 84# injectors, pick your poison on the engine management system, good external pump or at a minimum double pumpers.........
PT7080RH aka PT70 GT-Q dual ball bearing with a .85 A/R 3-bolt Buick turbine housing. It will support up to 850 flywheel hp when maxed out.
Don't care about class racing, 248 - 274 CI motor, 84# injectors and again your choice of engine management system, external fuel pump only.........
PT7480RH aka PT74 GT-Q dual ball bearing with a .85 A/R 3-bolt Buick turbine housing. It will support up to 925 flywheel hp when maxed out. On this type of motor, this turbo will spool very fast with a 3600 stall converter and will easily make enough power for 10 flat ETs at mid 20s boost levels. You won't have to upgrade the turbo unless you change your goals to wanting to run low 9's to high 8's.
On a full weight car (3600 - 3650#) you need to make around 750 hp to the tires to run 10.00s @ 135 - 136. Obviously, the bigger the CI of the motor and the more flywheel hp that the turbo can support, the easier it's going to be to make the required power. Meaning, you wouldn't want to put a turbo that will just barely make the required power, just to barely run a time/mph. If I were building a 248 CI low 10 second combo and didn't care about racing any class, I would choose a PT7480RH myself. Spool up between the 70 and 74 with dual ball bearing and 3-bolt style housings would be very similar. Probably within 500 rpms. Only difference is the size and weight of the compressor wheel.
Hope some of this helps.
Patrick
Explain please.
IMHO.... a TA45A turbo has the same HP potential with a 265 in motor as it would in a 305 ci motor....with camshaft and head/intake flow the same.... the turbo will likely make the same power at a lower boost on the larger displacement engine..... but the max HP potential would actually be the same....
Does this make any sense?
It may make a little more but not much more on the larger engine unless the exhaust housing a/r was increased beyond that of the smaller engine. There are too many things that could effect the power either way regardless of cubes with the cam overlap and engine speed causing an overspeed when running the turbo to its limits. Increasing the compression ratio will definitely make it much easier to hit the advertised flywheel hp numbers that the manufacturers put on their turbos. I dont understand the common misconception that keeping the CR close to 8:1 will benefit. Higher CR= more power, larger cam with less loss of driveablity, reduced BSFC, and increased spool (which is especially needed with the small engine/big turbos run on a lot of TR's today). It may require more octane but most of the really fast guys run C16 all the time anyway. I ran up to 25psi on top of 9:1 with 93 and alky.
- Joined
- May 26, 2001
Good points Bison. I guess the common misconception has to do with being able to run pure 93 octane only and enough boost to make some decent power, would be the only reasoning I could see with regards to the compression issue.
Well, there comes a point when the turbo can actually become a bottle neck on a larger CI motor. In other words, you wouldn't want to put a TA series turbo on a 274 and larger CI motor. This is mainly because of the super small compressor cover and how hot it will heat the charge temps when the boost is run up over 26psi. At least I would not recommend it.
I understand what you are saying about the turbo making the same hp at a lower boost on a larger CI motor, but is the rotating assembly comfortable running at that low a boost level?
Example, Let's say your 265 CI V6 with a TA-45a makes oh 650 flywheel hp at 28psi. (Just a guess for discussions sake) Now, you put that same turbo on a 305 CI V8 motor. It might make the same 650 flywheel hp at let's say 14psi. Now, is the compressor wheel comfortable running at 14psi? Maybe. Most compressor wheels have areas of flow where they do not like to be run at. This would be the area on a compressor map that is to the left of the dotted line. You would need to plot the flow on this 63mm wheels' compressor map to really know for sure if it likes 14psi or not.
Is the turbine wheel comfortable running at whatever psi it's running at? I'm not really sure. Exactly how much back pressure is being created before the inlet of the turbine housing? Now that we've added 2 more cylinders worth of exhaust flow and are using the same style and A/R turbine housing. My guess would be well past the acceptable 2:1 ratio. 2psi of back pressure for every 1psi of boost. So at 14psi of boost going into the motor, we do not want to see more than 28psi of back pressure before the inlet of the turbine housing. Which my guess would be slightly higher.
Some might argue that you would simply change the turbine housing. Yes, you can do this, but you need to make sure the turbine wheel is not too small to run on a larger CI motor. In the small V8 world, the P-trim turbine wheel is the smallest I would recommend on a single turbo setup. Twin turbo setups are a different matter.
The other things that come into play, when specing a turbo for a specific engine size is turbine housing options, turbine wheel selection and back pressure. A few Buick guys are fighting this battle as we speak. Trying to pick the optimum turbine housing A/R on a given motor size and still maintaining some sort of decent spool up. Some have run into extremely high back pressure readings and have had to step up to either a larger turbine wheel or larger A/R number. One of the biggest mistakes I've seen V8 guys make, is trying to run way too small of a turbo for their application, before doing any real homework on the subject.
Ok, I'll stop rambling on, hope some of this helps a little.
Patrick
Well, there comes a point when the turbo can actually become a bottle neck on a larger CI motor. In other words, you wouldn't want to put a TA series turbo on a 274 and larger CI motor. This is mainly because of the super small compressor cover and how hot it will heat the charge temps when the boost is run up over 26psi. At least I would not recommend it.
I understand what you are saying about the turbo making the same hp at a lower boost on a larger CI motor, but is the rotating assembly comfortable running at that low a boost level?
Example, Let's say your 265 CI V6 with a TA-45a makes oh 650 flywheel hp at 28psi. (Just a guess for discussions sake) Now, you put that same turbo on a 305 CI V8 motor. It might make the same 650 flywheel hp at let's say 14psi. Now, is the compressor wheel comfortable running at 14psi? Maybe. Most compressor wheels have areas of flow where they do not like to be run at. This would be the area on a compressor map that is to the left of the dotted line. You would need to plot the flow on this 63mm wheels' compressor map to really know for sure if it likes 14psi or not.
Is the turbine wheel comfortable running at whatever psi it's running at? I'm not really sure. Exactly how much back pressure is being created before the inlet of the turbine housing? Now that we've added 2 more cylinders worth of exhaust flow and are using the same style and A/R turbine housing. My guess would be well past the acceptable 2:1 ratio. 2psi of back pressure for every 1psi of boost. So at 14psi of boost going into the motor, we do not want to see more than 28psi of back pressure before the inlet of the turbine housing. Which my guess would be slightly higher.
Some might argue that you would simply change the turbine housing. Yes, you can do this, but you need to make sure the turbine wheel is not too small to run on a larger CI motor. In the small V8 world, the P-trim turbine wheel is the smallest I would recommend on a single turbo setup. Twin turbo setups are a different matter.
The other things that come into play, when specing a turbo for a specific engine size is turbine housing options, turbine wheel selection and back pressure. A few Buick guys are fighting this battle as we speak. Trying to pick the optimum turbine housing A/R on a given motor size and still maintaining some sort of decent spool up. Some have run into extremely high back pressure readings and have had to step up to either a larger turbine wheel or larger A/R number. One of the biggest mistakes I've seen V8 guys make, is trying to run way too small of a turbo for their application, before doing any real homework on the subject.
Ok, I'll stop rambling on, hope some of this helps a little.
Patrick
My original point was that for any given turbo ... it has a compressor map.... and it flows so many lbs of air (everything else equal).... and with that quantity of air... you can add so many lbs of fuel and it will make so many hp.....
I realize there are wheel speeds that come into play... that at certain velocities (usually too little compressor wheel RPM's).. that you can encounter compressor surge.... and there are wheel speeds too high that will overspeed and get out of it's efficiency range.
I realize there are wheel speeds that come into play... that at certain velocities (usually too little compressor wheel RPM's).. that you can encounter compressor surge.... and there are wheel speeds too high that will overspeed and get out of it's efficiency range.
That would be in the surge area for the turbo where it would also heat the air. A turbo, cam, and stall change will move the engine to where it needs to be to work comfortably most of the time for that given turbo. As you said a lot of guys with v-8's run much smaller than they need to especially with the BB turbos and the selection if exhaust housing available. They seem to usually be too small (overspeed or excessive backpressure for their ex a/r) or running too close to the surge line with the boost turned down, which is more common with the BB turbos. This is from what ive seen around here. Ill be sure to not make any of these faults when i turbocharge a bigger cube v-8 for myself. It will be nice applying everything ive learned over the last 13 years to a bigger engine:biggrin: . 1000+ hp +93 octane= no problem.
