Info on TT305, need just a little more help
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Info on TT305, need just a little more help
Okay, I'm doing a TT305. I'm making a Frankensteinian header/log for the exhaust. The goal is to make 500-600 HP under 6000rpm. I was considering using two T3 (.60/.48) turbos. I threw out a question to the guys at JGS Precision Turbo and here was the reply:
"For 500-600HP, you will need a 8-8.5:1 compression engine and around 15-20 psi of boost (depending on head flow, the better the head flows the less boost you will need). Those units would be fine for a 305, a little small for the 350."
Okay, so on a 305, I would use stock short block, and swap to L98 aluminum (vette) heads. That should drop the CR to around 8.5:1. Can these heads be ported, or will I run into valve clearance issues?
Secondly (and more importantly): I will eventually upgrade to a 350/355. Now if the above T3s are too small for the 350, what is a suitable turbo size (bigger T3, T3/4) that would work well on a 305, but be "big enough" for a 350?
Lastly, the setup won't be intercooled right away. How will that affect power levels and boost levels?
Sorry, I don't have the whole mapping concept down yet. Maybe I can begin to figure it out once my books arrive. If it matters to anyone, the 'charged air will be thrown into a SD HSR setup.
Thanks for any help guys,
MILT
"For 500-600HP, you will need a 8-8.5:1 compression engine and around 15-20 psi of boost (depending on head flow, the better the head flows the less boost you will need). Those units would be fine for a 305, a little small for the 350."
Okay, so on a 305, I would use stock short block, and swap to L98 aluminum (vette) heads. That should drop the CR to around 8.5:1. Can these heads be ported, or will I run into valve clearance issues?
Secondly (and more importantly): I will eventually upgrade to a 350/355. Now if the above T3s are too small for the 350, what is a suitable turbo size (bigger T3, T3/4) that would work well on a 305, but be "big enough" for a 350?
Lastly, the setup won't be intercooled right away. How will that affect power levels and boost levels?
Sorry, I don't have the whole mapping concept down yet. Maybe I can begin to figure it out once my books arrive. If it matters to anyone, the 'charged air will be thrown into a SD HSR setup.
Thanks for any help guys,
MILT
Last edited by MILT; 02-03-2003 at 06:46 PM.
#2
Intercooling will dramatically increase hp levels, it makes the boost more colder/denser and alows you to run higher boost without causes exseive detonator. Water alchol injection also does this but water is subadised for fuel and not as huge power gains. But it is expensive that is alot of air huge intercooler needed.
#3
"Intercooling will dramatically increase hp levels, it makes the boost more colder/denser and alows you to run higher boost without causes exseive detonator. Water alchol injection also does this but water is subadised for fuel and not as huge power gains. But it is expensive that is alot of air huge intercooler needed."
When your done with that hit pass the J my way I think we need a spell/grammer/intoxication checker for this board! hahahaha J/K You may want to proof read your posts a little more carefully I had a hard time trying to decipher what you were saying. No offence, I'm guilty of it too
When your done with that hit pass the J my way I think we need a spell/grammer/intoxication checker for this board! hahahaha J/K You may want to proof read your posts a little more carefully I had a hard time trying to decipher what you were saying. No offence, I'm guilty of it too
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Re: Info on TT305, need just a little more help
Originally posted by MILT
Okay, so on a 305, I would use stock short block, and swap to L98 aluminum (vette) heads. That should drop the CR to around 8.5:1. Can these heads be ported, or will I run into valve clearance issues?
Okay, so on a 305, I would use stock short block, and swap to L98 aluminum (vette) heads. That should drop the CR to around 8.5:1. Can these heads be ported, or will I run into valve clearance issues?
second....i thought there were only a limited amount of heads that will work on the 305 because of the small bore?
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Car: 98 Z28 vert
Engine: LS1
Transmission: automagic
Axle/Gears: 2.73 - boo racing yay MPG
305 heads are universally 58cc heads.
A 64cc head (like the l98) will put you to around 8.6:1 compression (if you started with 9.3:1)
I would not recommend doing tts on a stock short block unless you hate it and WANT to blow it up. ; )
A 64cc head (like the l98) will put you to around 8.6:1 compression (if you started with 9.3:1)
I would not recommend doing tts on a stock short block unless you hate it and WANT to blow it up. ; )
Last edited by Cronic3rd; 02-04-2003 at 11:34 AM.
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Car: 98 Z28 vert
Engine: LS1
Transmission: automagic
Axle/Gears: 2.73 - boo racing yay MPG
just thought of something - you could get some 76cc heads and have 'em milled to what ever you want/ need.
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Oh I don't hate the 305, I'm just starting with what I have--a stock short block. After it blows up, then I'd be happy to build a proper 350 for the setup!
So the L98 heads would be decent. A 72cc head milled (for 8:1 CR) would be better. Also, would I run into problems w/ valves?
Thanks again guys.
So the L98 heads would be decent. A 72cc head milled (for 8:1 CR) would be better. Also, would I run into problems w/ valves?
Thanks again guys.
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Car: 98 Z28 vert
Engine: LS1
Transmission: automagic
Axle/Gears: 2.73 - boo racing yay MPG
not to mention 76cc heads are everywhere - as long as you don't have an adversion to porting. 882 casting heads are every where but the will need to be ported massivly.
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Okay; I won't do the portin personally, so what type of port job should I get done (and what type of cost?)? Also, what size valves would be best on a 305?
Thanks
MILT
Thanks
MILT
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Car: 98 Z28 vert
Engine: LS1
Transmission: automagic
Axle/Gears: 2.73 - boo racing yay MPG
valves - the biggest that will fit (i am pretty sure 2.02 / 1.6 will fit)
if you get 882 heads they will have to be ported ALOT. There is plenty of metal there but most shops won't do that much porting if they will port heads at all. you might be able to get some one to do it for you though.
If you aren't adverse to spendin money just about every aftermarket head can be had with 72cc chambers and they will work on a 305.
if you get 882 heads they will have to be ported ALOT. There is plenty of metal there but most shops won't do that much porting if they will port heads at all. you might be able to get some one to do it for you though.
If you aren't adverse to spendin money just about every aftermarket head can be had with 72cc chambers and they will work on a 305.
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MMMkay. I think I'll start off w/2 .60/.48 T3s. I'll skip the heads for now. Once I get the "bugs" out of the setup or frag the motor (whichever comes 1st), then I'll upgrade to a 350 built for 8-1 compression. I can then upgrade to .63 housings to help feed the 350.
Or would it be worthwhile just to pull a set of 76cc smoggers from the JY for the timebeing? Would they flow better than a TPI 305 head?
Thanks
Or would it be worthwhile just to pull a set of 76cc smoggers from the JY for the timebeing? Would they flow better than a TPI 305 head?
Thanks
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Car: 92 Trans Am 'Vert
Engine: 305 TPI
Transmission: 5 Speed
The aluminum L98 heads have 58cc chambers, the same as stock 305 heads. They will keep your compression stock, in the 9.3 range.
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Car: 98 Z28 vert
Engine: LS1
Transmission: automagic
Axle/Gears: 2.73 - boo racing yay MPG
I sirously doubt the 882s will flow better than tpi heads with out alot of port work. Just stick with the stock heads and keep the boost low.
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Originally posted by Cronic3rd
not to mention 76cc heads are everywhere - as long as you don't have an adversion to porting. 882 casting heads are every where but the will need to be ported massivly.
not to mention 76cc heads are everywhere - as long as you don't have an adversion to porting. 882 casting heads are every where but the will need to be ported massivly.
The only problem with using 882’s are that they are crack prone, and a turbocharged application will only make that worse, though they will work. Iron L98 heads (64cc chambers) will put your compression at about 8.7:1 with stock style head gaskets, but they don’t flow even as well as the early smog heads, though they should still be OK up to about 5500 rpm. If you’re willing to deal with figuring out intake manifold problems, I’d seriously look at a set of vortec heads. They’ll flow more then you’ll ever use on that 305, relatively cheap and have a killer chamber/port design. Otherwise I’d be on the lookout for some 64 or 76cc pre lightweight casting heads or stick with the stock heads and intercool it or run race gas when you push it hard.
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Car: 1992 B4C 1LE
Engine: Proaction 412, Accel singleplane
Transmission: built 700R4 w/custom converter
Axle/Gears: stock w/later 4th gen torsen pos
Originally posted by 83 Crossfire TA
The only problem with using 882’s are that they are crack prone...
The only problem with using 882’s are that they are crack prone...
#18
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where do I get that? Well, I've only seen 3 cracked heads in person, and they all happened to be 882's. For that matter I just flipped through Lingenfelter's On Modifying Small Block Chevy Engines, p74 “The 882 heads… they are prone to cracks usually in the combustion chamber area.” And he even has a picture of cracked chambers in 882’s…
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