Hi guys,

It's looking like I'll be getting some money later on this year that I can use to build my engine a bit, & I'm just starting to lay out a plan - and it's making me realize how much I don't know...

I'm thinking about bumping it up to a 383, and I'm pretty certain that I'll go with a forged crank. Of course, forged pistons are a no-brainer, but I'm wondering at what level do forged rods become more than just a good idea? I'm trying to get the most out of the $$$ that I'll have to spend - not trying to build a "redneck special" from junkyard parts & baling wire, but (at the same time) I won't have the money to just throw at the project...

I guess what I'm asking is: Where is it mandatory to spend the money, & where can you make a reasonable compromise without hurting yourself too badly?

The application is a car that's likely to see 95% street duty (my "weekend car"), but is also intended for one or two salt-flat runs, & probably one of the "open-highway" events... At this point, I'm thinking of utilizing a centrifugal blower & aiming for 6-8# of boost.

Constructive thoughts/feedback/suggestions are much appreciated.

 

What kind of engine/car?

-Chris

 

That's not a whole lot of boost.

Look, the real gurus on this board have probably forgotten more about supercharging than I know, but your question is actually fairly basic.

You're talking about a fairly mild engine to be honest. Oh, you'll make a nice pile of power, well in excess of 500 crank HP, but you could probably get away with running a Scat9000 cast crank.

I'm not suggesting you do, but you can certainly look at the entry level forged crank and rods from Eagle or Scat, topped off with some SRP pistons.

Pay attention to your block prep and oil control, use a good aftermarket pan with a windage screen and use either a stock oil pump or a Melling. No need to get crazy. I don't know what you're planning to do with your heads, but probably the most cost effective thing to do is to send out your stock heads to someone like Lloyd. On a supercharged engine you'll want to focus more on the exhaust side, but no worries... Lloyd will do you right.

DEFINITELY get a custom cam from the same guy who does your heads. I swear to God, it's worth the money.

Replace your fuel pump with a quality aftermarket piece like the Walbro and get new injectors. 42lbs are a nice size. That's an opinion there and if one of the gurus says something different, listen to him instead of me.

Don't forget the rest of your powertrain...
I don't know what kind of tranny you have, but if it's an A4, get a looser converter for a better launch. Something with a stall speed in the mid to high 2000's, and definitely go with a company like Edge or someone else in the same league. In terms of your rear, and assuming it's stock, then at LEAST get a T/A cover to stiffen it up and help it stay alive.

 

Thanks LameRandomName, I appreciate the feedback. Chris (& anyone else), the car is my '89 GTA with the L98. I've been stockpiling parts for this for a little while, so far I have a set of Hotchkis SFCs, an MSD 6AL, a StealthRam intake & a set of AFR 195 heads, all sitting in the house ready to go onto the car. (Probably a couple of other fairly minor things that I'm forgetting right now...)

Those are in addition to the upgrades I've already made to the car - most of the "free mods", 24# injectors, Jet-Hot coated SLP headers, full exhaust, a CAI, & some mild head work (milling & 3-angle valve job) that was done right after I got the car. Oh, and the Firehawk SZ-50s that I freakin' LOVE...

The one thing that I'm pretty definite on is that I'm going to remove the A4 that's now in the car & replace it with a T56 - my vision for this car has no room in it for an auto. Of course this means that I'll (more or less) need to swap to deeper rear gears to make up for the torque multiplication that I currently have with the deep 1st gear & the tq converter... I'm thinking about going with 3.73s, but I'm still pretty flexible on that...

Anyway, between the tranny swap & a couple other upgrades I'll be doing (definitely better brakes, a good radiator, and maybe lowering it & making sure that the suspension is up to the task of handling the power)... Well, I'm hoping that I'll have enough for the blower - which is why I'm asking where I might be able to make reasonable compromises for a (mostly) street car...

Thanks again for the feedback, it's much appreciated.

 

Oh, one more thing I forgot to mention - Whichever rear gearset I choose, I will definitely be performing some basic strengthening mods like the T/A cover, synthetic fluids, etc.

Drag racing/hard launches just don't seem to "float my boat", so I'm hoping that I can put off the $2500 9-inch/12-bolt for a little while...

 

OK, I'm going to give it one more attempt to get this answer before abandoning the question:

What are some *reasonable* compromises that can be made for a blower car that will be (roughly) 95% street-driven?

(Not to denigrate or minimize in any way what "LameRandomName" said above, but I would really like to get a full range of opinions...)

Thanks in advance guys.

 

You could use a 5140 (?) based rotating assembly. It's a step up from the cast stuff, but not as tough (or costly) as the 4340 stuff. Also, keep the cam specs to a friendly 6000 RPM red line and stick with it.

For boost, you won't need deep gears in the rear, unless you like buying new tires alot.

 

6 to 8 P.S.I. is pretty mild in the world of centifugal blowers, as mentioned above, some entry level cast cranks and rods from scat or eagle would suffice. The only place I would never skimp on a power adder car is the pistons, get a descent set of pistons. Shoot for a compression ratio of around 9 to 1. If you're going to upgrade injectors I would suggest going all the way and getting the 60 lb versions just so you dont have to upgrade again later, there really isn't a good argument against having bigger injectors than you need, but too small will limit power. Since you're running the traditional small block you are blessed with tons of options on heads, dont need to go crazy, just some descent flowing street heads. Even stock heads will flow an amazing amount of air when the air is being compressed . I know several guys that have made well over 500 RWHP with the stock LT1 castings. In your case I'm going to recommend some GM Vortech heads, awesome budget heads for less than 600.00. Yoy will have to have the intake bolt pattern for your intake drilled and tapped into the heads, but it's a very minor and common procedure, I believe some companys sell the heads allready prepped in this manner. Follow the advice given above for the oiling system and make sure the fuel system is capable of supplying enough volume.
Ok, tired of thinking now, ask if you have any more questions