I'm wondering what you have to put in the engine parts wise so it can handle boost?

And which crate engines (350's) can take boost?

For the record I'm looking/thinking at around 10psi of boost.

Mark

 

Where is the boost? Is it positive displacement blower boost or centerfugal boost? For 10lbs of boost, I would go with something like the zz4 short block. There are lots of crate motors with the zz4 short block but anything with forged pistons should be plenty strong enough for most boost.
I know that cast pistons can handle 10psi but it all depends on how much insurance you want. Heck, cast pistons, 2 bolt mains, iron crank, PM rods (this is the minimal), and stock everything else can handle 10lbs of boost so long as you never detonate from too much timing OR bad gas.
What is your budget or what do you want exactly?

 

I am no expert, but here are some general rules of thumb.

Anticipate an engine management system to run the boost and fuel injection. The stock system can't do it (according to whatI've read/been told). If you are trying to pass the sniffer figure on pairing up the aftermarket system with the stock system, as the stock system is required to run the emission stuff.

The bottom end has to be built for a power adder (forged crank and billet rods)

Aluminum heads are required to run 10 psi of boost.

Use ARP studs everywhere.

Compression should be at most 11.0:1 - The higher the compression the lower the boost - 8.0:1 and you can run just about all the boost you want.

Plan for intercooling to run the boost.


As an aside I know of NO crate engine that is designed to run with boost. It is a wiser thing to assemble the parts yourself.

I hope this puts you in the right general direction. Corky Bell's book and Hugh MacInnes's book are two investments to help you plan you endeavor.

Jason

 

I'm looking for a 350 with converted LT1 intake + an eaton M112 supercharger combo to put out numbers in the range of 350hp and 400tq. It has to be streetable as it will be a daily driver. That is the about what I'm looking for.

My budget is extremely limited but I'm still only in the planning stages so I still have time to save up the cash required for this kind of setup.

Thanks,
Mark

 

I don't think that it is neccesary to use a supercharger to get to those numbers. If you just want to use one it is probalby a good idea to anticipate 50 to 100 more on both numbers.

Figure on $3-4000 for the basic hardware alone. The little stuff to make it work/reliable will have you spending more.

I have never done it, but from the research I've done for a similar project this is what I've discovered.

GM has a 383 crate that pretty much hits your numbers without boost, so you might want to consider that.

Jason

 

I'm not planning on using the supercharger to make those numbers because I think the engine can't do that alone. I want to use a supercharger because I think it would be cool. I had planed on building the 350 for less power then I wanted that way when I put the supercharger on it it would be producing about what I planned on.

Mark

 

STRONG, You need forged internals, 4 bolt block. 10 lbs of boost is actually a lot. you do the math, my motor make 304 RWHP NA and 435RWHP on 9lbs of boost on pump gas. Thats a 30% increase at the wheels. going thru a 700 trans there is about a 25% loss. so that puts my engine output around 550. So you need to build your engine to support 550 min. Figure out your end goal and build from there. I believe that you will always want more power so build it with all 4340 stuff. This way when you want more power (as you will) your engine is ready for it.

 

umm.. that really doesnt make much sence to me...

 

Forged rotating assembly. Low compression ratio. Timing and fuel controls. Scan tool to watch what is going on.

biggtime,
A 700R4 doesn't suck up that much. Figure 18% at most. Unless you are running a loose non lock up converter.

 

https://www.thirdgen.org/techbb2/sho...42#post1278542

 

3200 non lockup. Yes it does suck up that much!

 

Yikes! I wouldn't run around without a lockup. Mine is a 3200 also in the 2004R. I lock it up at WOT and its like another gear. Plus I get that great MPG on the highway

 

I bought a manual valve body turbo 400 to replace it. The 700 would never live anyway. I don't like that locking it up under WOT, I did it to my typhoon a couple of times. plus all that clutch lining getting shredded and going thru the trans.

 

I agree that the TCC shouldn't be on under WOT for those exact reasons. Under WOT you had better have a high TPS value (duh) so why not have the TCC no lockup under high TPS?
I still think the extra goodies are only for insurance. I've seen a stock long block blown L98 running high 10's for as many seasons. That's with a vortec blower and stock eprom with an FMU. I've also seen forged blocks self destruct because the oiling system was neglected and it through a rod. Then I've seen detonation kill a built up 355 in less than a season running na.
My point is simple, you can boost anything so long as you're careful not to detonate or run low oil pressure.
I'm actually looking into the m112 on my 330ho crate engine. It's got a 9.1 to 1 compression ratio so 6-8 psi should be fine with the cast internals (PM rods the only forged part).

 

Well, if your goal is 350hp then just buy one of the crate engines out there that makes more power then that.

If your goal is to run boost and stay cheap… well, I would do something completely different. First, none of the crate engines really make a good boosted engine. I'd look for a good used shortblock that someone is giving away (will probably be a 305… most 350's fetch a couple hundred $ in wasted shape, where you can get a good running 305 for free).

Build the bottom end for the rpm you will be turning, don't worry about hp. In this case, there is no real need to turn any great rpm's, so I'd use a stock crank and rods (pre '89 or post '95 for the rods). If you plan on seeing some road course time I'd consider splayed aftermarket mains, but if not I'd keep them stock also. Pistons I'd get something appropriate to blower use… forged, run larger ring gaps with the top ring further down then a normal NA piston. If you start with a 305 here you have an advantage since you can use cheap flat tops and then run 350 heads for lower compression. If you have cast or hypereutectic pistons sitting around that cost you nothing then use them, but if you're going to spend any money on them then get forgings, they'll survive more abuse. The heads need to match your piston selection. I'd be shooting for 8-8.5:1 compression, just because it will give you more flexibility later on and make dead on tuning less critical. I'd err on the low side if you're going to stray outside that range. Skip the aluminum heads; there is nothing good and cheap out there.

If you play your cards right and do the assembly yourself, you should end up with a 305 that would be dead reliable, bulletproof, capable of at least 2-300hp over your hp goals and all for $500-1000.

 

exactly.

as long as you're keeping it within reason, no prob..

and since you have no goal for real power, you can choose even the whimpyest of engines and boost that.... 350hp boosted is hard..... hard to get that LOW

 

I guess the 200's are better equipped to handle it. Grand National owners have been doing it since the 80's.

After snapping the input shaft on my original trans, I had it rebuilt to take anything. Along with a multi disc Vigilante lock up converter. But the stocker was fine until that happened. 11 second passes(2800 converter) and many low 12 second passes, the latter completely stock with just a shift kit.

 

83 Crossfire TA,

If I read your post correctly and processed it right then what you are saying is:

It would be cheaper and easier to make a supercharged 305 put out around 350hp then it would be to make a 350 do that because slapping a supercharger onto a 350, that is already making decent power, would make it hard to keep it in the power range I'm looking at, while still maintaining enough boost to make the supercharger worth the while? Right? Or did I fall asleep somewhere and miss the whole point? Yeah it's only 7:00pm and I'm running on empty.

Mark

 

yea.... i think thats about right...

your more efficent taking a smaller motor (V6 even) and boosting it to make that power then to take a 350 and bearly run any boost thru it...

not to mention, if done right, you should get EXCELENT gas miliage off boost. (90% of the time on the street)



athough personally id go the oppisite way, and just build the 350 and make more power... but im a power junkie.. i always need a lil more... :lala:

 

Close enough.

To be honest, I think that there is enough advantage with going with something closer to a 305 (over a 350) for regular street use that I'm tempted to do that swap in one of my 350 powered vehicles just to prove a point... (even though I have a few 350's sitting around and a bunch of good parts..., so it would actually cost me more)

 

Cool. It's good to know I can atleast comprehend some of this stuff......but then again I do like to program where theory comprehension is a must.

How much do you think it would cost to build a 305 for the kind of power I'm looking at?

Thanks a lot!
Mark