Is the LT4 sufficiently beefier inside than the LT1 such that it will tolerate a super charger at say, 8psi, better than an unmodified LT1? Is it generally acceptable to bolt a blower onto an LT4 without beefing up the internals?

Specifically, if one saw an LT4 car for sale with an ATI ProCharger on it, but no known internal beefing done to the motor, would that be okay or will/would the engine be short lived? 29,000 on car, ProCharger installed 4000 mile ago.

 

The LT4 is slightly stronger, but the compression ratio is higher which is a bad combination when running boost. You'll only get away with running a couple psi of boost. I'm not even aware of any companies that make LT4 kits except Carrol. Might be others thou.

I wouldn't even think about putting a SC/turbo on my LT4... not without a complete lower end rebuild with forged internals and lower comp pistons.

 

LT1 can run at a safe 8psi if tuned properly. Otherwise, kaboom. I think I've read on the forum not to go over 6 ( even intercooled on the LT4 ). The compression is damn high.

 

Well, let's put it this way, Arizona Speed and Marine refuses to put superchargers on stock LT4's...so I wouldn't.

 

:iagree:

 

Its not worth the money of a blower if your not gonna use it to its potential, just port the heads for a lot cheaper.

 

LT1 can handle 8 lbs boost with intercooler
LT4 can handle 6 lbs boost with intercooler

You really want to lower your compression to 9:1 to get the full benefits of a SC and be able to run 12-14 lbs of boost. While you're down there, may as well go to a 383 or 396. Then you need to port the heads...... :rolleyes:

 

It's a vicious chain isn't it? :D

 

Good advice given so far......

To begin, the LT4 has marginally better crank and timing chain setup but has higher compression. Both have hyperutectic pistons without forged rods. These engines are not really designed to bolt up superchargers like say the 4.6L OHC Fords (which have much lower compression ratios). On the Fords, it is most economical and very effective to go straight to a blower and a couple of bolt ons to acheive good power. On the LT engines, bolt ons are more effective and especially heads/cam and then fully built strokers etc. before really considering boost , IMHO.

If you want to have a semi reliable supercharged LT motor , you really need forged pistons and rods at least with a lower compression ratio. Intercooling would also be a good idea and a higher capcity fuel system (injectors, pump etc.) and radiator would be good ideas as well. Head flow is very important as well and this is where the LT4 would really outshine the LT1 stock v. stock heads with boost. Again , look at what 4v Cobras can put out with a blower. Just 10psi on a relatively stock 96-8 Cobra with a Vortech kit, MAF , Hpipe and tune and you are at 450 rwhp....those 4v heads FLOW well (even better than LS1 heads, stock v. stock). So, the LT4 heads with its significantly better flow numbers can make a fair amount more hp with a blower than an LT1.

Hope that helps..... :seeya

 

Why stroke and then go power adder??? What for??? Show off then puff??? You either do one or the other. Not wise to stroke a forced induction engine unless you spend to dollar and still what for if you can atain the same power just by increasing the flow (not necesseraly boost)

Later

 

I have a friend with a SC Impala SS and he dropped a second in the 1/4. He has 120k on the orignal stock LT1 engine. He is either running 4 or 6 psi with his.