Turbo with near stock C/R?

K

kerb12

Well-known member
Hey all, I've been slowly building up my 200 over the past few years, and looking for what my next step should be and toying with the idea of FI...

Right now it's a stock rebuilt block, bored .030, with a COMP cams 260H. Head is a large log with a direct mount Autolite 2100 1.08, and long tube headers. A decent amount of work was done to the head - 1.75/1.5 valves, 3-angle valve job, some polishing, dual springs with dampers. I'm also using a DSII with an MSD controller.

Head chambers are 54.5CC and I'm using a Victor gasket, so if I did the calculations right that would be 8.66:1 CR, just under stock. I've read posts that say you generally don't want to go above 8.5:1 otherwise you'll get detonation... Should I just keep it the way it is now and forget about a turbo? Anyone running a similar configuration safely under low boost? Maybe 6-7psi?

-Nick
 
You really need to look at the total package rather than just one component. 8.66:1 with modest boost should be fine with proper fueling, and you can always throw in an intercooler and/or water injection to keep intake charge temps down.
 
Thanks, I'll keep researching and try to come up with a more specific plan. Glad to hear it's possible...
 
Bone stock bottom end outside of a cam swap, big log head and 2 barrel carb I ran 20psi no problem from a TE44 turbo. Fuel is key, I also ran a front mount intercooler to help cool things down. Ide do it again in a heartbeat and just about did but decided to build the bottom end a bit and try to push it a tad more. These motors like boost come to find out and will blow the headgasket before they put a window in the block. Toss some ARP head studs in, normal everyday no big deal Felpro headgasket and then make sure it gets plenty of fuel and you will have plenty of fun for a good amount of time!

Matt
 
Now that's what I wanted to hear! Looks like I have a winter project. I just need to convince myself that the hp increase is worth giving up my headers... I love the sound my dual exhaust makes now.
 
You can double your horsepower and gain another awesome noise...turbo spool. Mine exhaust sounds really close to how it did with my dual headers. 3" downpipe split to dual flowmaster and then out the back.

Matt
 
drag-200stang, are you seriously running 9's with a 200??? That's amazing. Are you using the aluminum head? I'm not shooting for those kind of numbers, I'd just like to be in the 14's. I want it to still be a reliable daily driver, plus it's a convertible and I don't want to have to mess with roll cages. I'm hoping with the mods I've already done, adding a turbo with 6-7 psi could get me there.

66Sprint6, what size exhaust do you have? I'm running dual 2" to Dynomax turbos. Is that too restrictive for a 3" downpipe?
 
You will nail 14's no problem. Mine on the stock peg leg rear end running and 14psi blew the head gasket (terrible fuel setup) and ran a 14 and that with a terrible 60ft. With a proper fuel setup and decent launch you could EASILY run what you want and daily drive the car all day long. If you want to keep the 2" exhaust, run a 2.5" or 3" downpipe to a cutout and then to the 2" exhaust. Then with the cutout closed you go thru the exhaust and keep your sound, when you want to free it up, open the cutout and let it rip. I have one on my car just before the 3" "Y's" to the 2.5" duals.

Matt
 
Yes it went 9s when 10s was fast. Large log 74 ,with .100 larger ex valve.78 and up are better with 80-83 octagon the best. People think I ran high boost or the engine was radical,just common sense port clean up mild solid cam. forged flat top pistons 15 pounds is all I used. But the car was built like a pro stock car of its time, drag only. These engines love boost, intercooler water alcohol inj. .Just watch your tune .
 
drag-200stang":32dgyvf1 said:
Yes it went 9s when 10s was fast. Large log 74 ,with .100 larger ex valve.78 and up are better with 80-83 octagon the best. People think I ran high boost or the engine was radical,just common sense port clean up mild solid cam. forged flat top pistons 15 pounds is all I used. But the car was built like a pro stock car of its time, drag only. These engines love boost, intercooler water alcohol inj. .Just watch your tune .
Click to expand...

Interesting-You used a cleaned up cast iron exhaust manifold like the C8 into the 3 in down pipe? The log intake intact, but modified for the bigger carb along with the mods you described? Then big exhaust like 3 in out the back. If that cast iron ex manifold is not a drawback, it makes for compact workable plumbing.
My Way
 
my way":1hqxswai said:
drag-200stang":1hqxswai said:
Yes it went 9s when 10s was fast. Large log 74 ,with .100 larger ex valve.78 and up are better with 80-83 octagon the best. People think I ran high boost or the engine was radical,just common sense port clean up mild solid cam. forged flat top pistons 15 pounds is all I used. But the car was built like a pro stock car of its time, drag only. These engines love boost, intercooler water alcohol inj. .Just watch your tune .
Click to expand...

Interesting-You used a cleaned up cast iron exhaust manifold like the C8 into the 3 in down pipe? The log intake intact, but modified for the bigger carb along with the mods you described? Then big exhaust like 3 in out the back. If that cast iron ex manifold is not a drawback, it makes for compact workable plumbing.
My Way
Click to expand...

Sorry Kerb for the derail.

My Way, yes the exhaust manifold came from Ak Miller in '74. It was a C8 manifold with 1/2" mild steel flange welded to it just below the X. The large log head was modified by extending the manifold at both ends. The thought was to increase plenum area and to keep air fuel mixture from bouncing off the dead end wall making 1 and 6 lean. But unfortunately it fixed that but caused 2 and 5 to run lean. New build will fix that with individual port injection. The manifold was not modified for a larger carb, just the radius cleaned up. Partial kit I got from Ak Miller had no intercooler. I added a water to air intercooler that bolted directly to the one barrel carb opening. This is also a draw through set up. It was thought at the time that carbs wouldn't work well under boost. That's been proven wrong, blow through is the best way of doing it other than MPEFI. I fabricated up a draw though manifold and used a 600 Holley double pumper. I tried an 830 that actually made more power but I didn't run it on the car because I was chasing ignition gremlins. The down pipe was 3", only 2 foot long and just dumped under the car. Turbos respond better if you keep the back pressure to a minimum. The stock exhaust manifold I feel is fine for mild builds. If you haven't seen it, there's a pic of the engine on Classic Inlines boosted engine pics. Its the one with the motor plate. My new build I'm building a 6 to 1 - 1 1/2" stainless steel tubing header.
 
1964 Standard NA headers work well with 1-1/2 . 1-1/2 16 ga. is 1-3/8 inside diameter which is a fair amount larger than the port. Talked to some turbo Buick guys , thats what they use ,their engine is close to same flow ,its a little bigger but we can rev higher.
 
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