okay, i've been thinking of ways to deal with the low compression i suffer from because of my aluminum l98's on my 305. i run thin head gaskets right now, but i've been toying with a twin turbo setup in my head.

the main reason i'm thinking of using turbos is because the l98 heads and zz4 cam that are in my 305 right now are going into a 350 after the 305 blows up, and it makes more sense to use turbos because high compression pistons and such for a 305 wouldn't transfer over to a 350.

firstly, i'd estimate that if i ran a normal (safer) head gasket i'd end up in the 8.1 - 1 range on compression. sound right?
well, if this is true, according to what people said in the sticky about turbos, i should be able to get away with a lot of boost, right? like, would i be able to run twin 8 pound turbos, or that just too much?

also, would the zz4 cam work safely with a twin turbo setup? it's a cheap cam anyways, so it's no big loss if i have to replace it. i also have a more or less stock TPI setup, would this be a problem?

basically, what all am i gonna need to get a twin turbo set up on a 305 TPI?

 

Aluminum L98s have 58cc combustion chambers. same size as your stock 305 heads. Though still OK for turbocharging, your compression is stock, well actually higher with small head gaskets.

 

they do have 58cc chambers, which is the same as stock, but they are aluminum and dissappate heat much quicker. they were put on vette 350's with 58cc chambers because they have to be that small to maintain the normal 9:1 compression...or so i've always been told.

 

TTT

would a pair of t3's work well with my setup?

 

bump

anyone?

 

yep just like the other 1000 or so posts with this exact same question; yes.

go get a pair of T-bird T-3's from a wrecking yard or from ebay and start building your manifolds.

I hope you have good welding and fabrication skills

 

I know all about the heads.

so what if they're aluminum. your compression is still the same. you don't get 8:1 compression by switching from iron to aluminum.

Vette 350's have more dished pistons than a f body 350, so they run smaller combustion chamber volume for about the same over all volume. You had 58cc chambers stock, and you have 58cc chambers now. therefore you have no change in compression except for that headgasket.

 

yes, i'd assumed that normally you'd stay the same compression using heads with the same size chambers....you might want to talk to five7kid, and practically everyone in the TPI forum, who are all saying (and have said) that compression is lower with aluminum heads. not to say you are wrong, just saying this is what everyone and their brother tells me, I didn't just pull it out of my a$$ or something.

 

i would of shelled out extra cash for a supercharger if it didn't actually, i'm pretty much a novice with welding, but i have a buddy who's setting up a TT on his 4th gen T/A who knows what he's doing and is gonna help me out quite a bit. i've got a lot of learning ahead!

 

Hey B4Ctom1, do you have to be such an ******* just because someone asked a question that may have been asked before. It's ****** like you that have given this site a bad name all over the internet.

 

first of all calm down, secondly your new, stick around for awhile and you'll agree with b4ctom1, im not trying to be an a$$ but if people (including me) would just do a search they would have they're answers

also as far as the heads lowering compression, they say that because your going from a 4 inch bore 350 to a3.75 or whatever bor on a 305, typically using 350 heads on a 305 lowers the compression, but its not a good idea because it hurts your quench... i have no clue if the L98s lower your compression or not, and i've heard they are an "ok" swap for a 305 as they do not hurt your quench that much... in any case you definately dont have 8.1:1 compressions its probably more like 9.0:1, you can still run boost though... search for saturn5... he ran twin M90 blowers at 12-14lbs for about 1 year on a stock 305, i personally would recomend no more than 6-8 psi unless your good at tuning or you can blow your motor up, and i've heard the stock TPI cam is a great blower cam, as far as turbo's just about any twin T3's will work, search for 89JYturbo.. or something like that... and lastly do a lot of research because even with junkyard parts by the time your done your gonna be into it about $1500-3000, you sound like its a temporary set up untill you get your "high compression 350"... $3000 is a lot to spend for a temporary set up

 

thanks for the reply. i doubt i end up spending this much cash. my buddy who's helping me has set up JY TT systems before, and he anticipated MUCH less than any $1500. realize we're going the cheapest route possible (using radiator hose, etc...it'll be ugly, but i don't care), and his dad owns a junkyard about 15 miles from my town, so the JY stuff will pretty much be free. i've already got the 350 sitting in a 1985 suburban that's on it's way to the JY (rusted and smashed...engine block is in great shape though), and outside of converting it to hydrolic roller, it's ready to go, and i might just run the turbos on it too (obviously with lower boost), because i'm gonna be keeping the TPI, and i want it to still have some high end punch.

 

stevedave454, did you read any of the other comments in this post. If your stock 305 heads have 58cc chambers and the aluminum vette heads have 58cc chambers, the compression ratio will stay absolutely the same.

I may be new here, does that mean I don't know anything, I guess so. Apparently the more you post, the more you know, so you're on your way to becoming a guru. Just keep sticking up for the other a$$holes on here. Why post if you don't know what the hell you're talking about, just to drive your count up (just like the people who post to tell you that you're a stupid newbie for not using the search function)?

80smetalfan, you're on the right track about the aluminum heads dissipating heat faster than iron heads. By dissipating heat faster, you will stay out of detonation better, allowing you to run more timing. Detonation is your worst nightmare when turbocharging. You obviously are on the right track, good luck. I'm running a single t-88 in my trans-am and am having the most fun with it than any other car I've built thus far.

 

You know, B4Ctom1's response is totally appropriate for the question… this has been discussed and rehashed tons of times just use the damned search. If you don't find your answers there (have something unique), THEN ask. Just like you would on any other board.

While I'm at it, don't any of you read the rules posted at the top of each board? To start, sigs are limited to 400x100 or 5 lines… your pic is almost 2x that…

 

Chill out guys.

Check your egos and turn this conversation around. I know its been asked a thousand times. Either give the correct information, point the guy to a thread that has the right information or flat dont reply.

 

my answer was not meant to be as a jerk. It was just meant to be short, to the point, and consise. There is nothing that I said which should be offensive.


[snotty]Im sorry that it wasnt "sweetsy, pleasy, thanksy" enough for you.[/snotty]

 

You're my hero.

 

I try