Which is the better AR...68 or .81?
Launching!
Joined: Feb 2011
Posts: 234
Likes: 1
Sure wish you had done some data logging and testing before you tore it apart...
Specifically...Drive pressure and the DP across your intercooler.
You are just shooting in the dark without good data.
What size is your intercooler ? E-bay or ?
Where are you measuring your boost at ? Pre or post intercooler ?
What's the specs on your "custom" cam ? Was it spec'd for your 6.0 (and your 8.5 comp.) or you old 5.3 ?
What are you running for exhaust ?
I understand your desire to run the On3 turbo's. (I'm a cheap bastard at heart) It could be as posted that you have reached the limit of the turbines but without drive pressure data it is just a educated guess.
If you are dead set on running the On3 turbo's, I would grab a leaf blower and do a quick check on what the dp across your intercooler is first.
If it is high, you are not getting all the boost your On3's are putting out and you are increasing the back pressure on the drive side as well.
I guess it is your call...
A) Do you want to try and get the max you can out of a pair of On3's ?
(I would get the largest a/r you can get and try reducing any restrictions etc. Also since you are running e85 and 8.5 comp. I would be fairly aggressive with your timing)
B) Spend the extra coin and turn it into a "rocket" by throwing a set of s366's and a good flowing intercooler on it and take full advantage of your built 8.5 comp. motor.
Either way, have fun and keep us posted...
Specifically...Drive pressure and the DP across your intercooler.
You are just shooting in the dark without good data.
What size is your intercooler ? E-bay or ?
Where are you measuring your boost at ? Pre or post intercooler ?
What's the specs on your "custom" cam ? Was it spec'd for your 6.0 (and your 8.5 comp.) or you old 5.3 ?
What are you running for exhaust ?
I understand your desire to run the On3 turbo's. (I'm a cheap bastard at heart) It could be as posted that you have reached the limit of the turbines but without drive pressure data it is just a educated guess.
If you are dead set on running the On3 turbo's, I would grab a leaf blower and do a quick check on what the dp across your intercooler is first.
If it is high, you are not getting all the boost your On3's are putting out and you are increasing the back pressure on the drive side as well.
I guess it is your call...
A) Do you want to try and get the max you can out of a pair of On3's ?
(I would get the largest a/r you can get and try reducing any restrictions etc. Also since you are running e85 and 8.5 comp. I would be fairly aggressive with your timing)
B) Spend the extra coin and turn it into a "rocket" by throwing a set of s366's and a good flowing intercooler on it and take full advantage of your built 8.5 comp. motor.
Either way, have fun and keep us posted...
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2 S366's for 1000.00 would be sweet! I see alot of s366's for ~650.00 on ebay, but have a best offer option. I bet 2 for 1000-1100 is possible! I'd do it, but I got no money!
Thread Starter
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Joined: Oct 2011
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I am going to pull the intercooler off and see how it does first. I am using an ebay intercooler. I didn't use one when I was 11.0 to 1 compression but it blew up in the 1/4 after 7 months. I am only 8.5 now so really don't think I need it. I think that is what is holding up the turbo's, plus it is some extra weight. Once I get the trans fixed I plan to test what my back pressure is.
Thread Starter
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I did call around and could not find anyone to go cheaper than $600 per turbo. That's just too much for my blood right now. I think if I pull my IC and put my meth injection back on I will get rid of a ton of back pressure. First I have to get the trans and convertor done before I do anything.
Think there have been a couple guys with around 600 on a single 70 on 3. I know there was one car that just made like 740 or 750 on a single 76 on3. I can't imagine that the turbine in maxed if people are able to make that much with a single on a v8.
Launching!
Joined: Feb 2011
Posts: 234
Likes: 1
The more I ponder this...
The more I think you have a bottle neck with your intercooler.
Each of those On3 turbo's are only feeding what is basically a 185ci. 500hp engine...
I don't see the turbine on those being maxed out at that level.
Really wish they had maps on those turbo's...
The more I think you have a bottle neck with your intercooler.
Each of those On3 turbo's are only feeding what is basically a 185ci. 500hp engine...
I don't see the turbine on those being maxed out at that level.
Really wish they had maps on those turbo's...
Thread Starter
TECH Fanatic
Joined: Oct 2011
Posts: 1,425
Likes: 0
The more I ponder this...
The more I think you have a bottle neck with your intercooler.
Each of those On3 turbo's are only feeding what is basically a 185ci. 500hp engine...
I don't see the turbine on those being maxed out at that level.
Really wish they had maps on those turbo's...
The more I think you have a bottle neck with your intercooler.
Each of those On3 turbo's are only feeding what is basically a 185ci. 500hp engine...
I don't see the turbine on those being maxed out at that level.
Really wish they had maps on those turbo's...
Thread Starter
TECH Fanatic
Joined: Oct 2011
Posts: 1,425
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Without looking at my cam card it is something like a 232/234 .604/114 it's a custom tick cam. My 6.04 was with a used XER273 cam also. I had forgot about that. The custom cam should have picked it up a ton more in ET. Again, I think that cheap ebay IC is holding it back. We'll see.
wicked69,
what is the iat at 20 psi? that will be a clue as to the efficiency of the compressor and if you are off the map(assuming no intercooler of course)
then,
what is the back pressure? you wanna know if the turbine is expelling exhaust efficiently. you can use the fuel pressure circuit on the holley.
what is the iat at 20 psi? that will be a clue as to the efficiency of the compressor and if you are off the map(assuming no intercooler of course)
then,
what is the back pressure? you wanna know if the turbine is expelling exhaust efficiently. you can use the fuel pressure circuit on the holley.
I like this idea. Heck you can also use the oil pressure circuit also for datalogable pre and post i/c #'s. Nice tip
