LSX Fan

I just ordered an Ultima GTR kit and will be ordering my engine within the next 6-8 months. I've thought about what I plan to do and want to present it here to see what you guys think.

I have some experience with LS engines, but this forum is known for its experts and because I'll be spending a CHIT load of money I want to make sure It gets done right (with as few wasted dollars as possible) the first time. So here's my proposed specs and part selection:

The mill will be a supercharged 388ci (6.35ltr) LSX block w/9.5:1 compression. Proposed WHP around 700. Rod ratio is 1.7:1 and proposed redline is 7500rpms. I'm restricted to a G96.88 tranny so I kept the stroke fairly stock. Boost will be limited to around 12-14psi at 7500rpms. Totally streetable everyday driver.
OK. That's some of the major items. I posted earlier but got no response...hopefully I can get one now. So...what do you guys think?

bczee

iTrader: (12)

Seems you got a good plan going and know what you want. Being that this swap is for a Ultima GTR kit, I am without any working knowledge of this car, other than have seen a few before. Well be a killer track car. I'll follow your build.

Good luck and keep the build thread going.

BC

LSX Fan

Thanks BC! The GTR is a very awesome car. Lightweight, great handling and simple design. Some are built for pure speed and others are built as weekend toys. My goal is to build a daily driver that can blow the doors off any Ferrari or Porsche and still be relaxing enough to drive to the grocery store.

It'll be a while before the parts actually arrive and even longer to get into the meat of the build. I just want to get some input on my selection of parts here before commiting to them, then once I start I'll begin a real build thread.

Thanks!

Bilster

iTrader: (21)

Should be one hell of a build. Saw a feature on one in Car Craft. Jeff Swartz is the owner. His name crops up in various LSx events. His build had a relatively mild LS6 build and it crept into the 10 second ET bracket. These cars don't need much to make them super cars. If his did 10s with a mild LS6, I can only ask the question, "Jeez....how fast do you need to go?!?!"

http://www.carcraft.com/featuredvehi...gtr/index.html

LSX Fan

Yeah...they will get moving in a hurry. The factory model with 720hp @ crank will do the quarter in about 9.8 sec! That's some serious speed.

I'm not a drag fan, but I do like the idea of being able to get some g's in my back every once in a while.

LSxChevelle

iTrader: (4)

Have you considered a LS3 block? Lighter and definitely capable of handling that power.

LSX Fan

I originally thought about using an LS3 block because it's cheaper (of course), but I'm not comfortable with pumping 750-800 reliable, supercharged horses through an aluminum production block.

If it were something I'd use occasionally, then I'd have no issues, but a daily-driver?? Naw...rather not. Besides, outside of being lighter and cheaper, there's absolutely no reason to compromise and choose an LS3 over an LSX! And since the Ultima is only 2,200 lbs and was originally designed to use an iron block SBC, I'm not concerned about the additional weight.

I'll take the security of an LSX block over an LS3 any day of the year.

bczee

iTrader: (12)

Yeah. .it would only about 80-100 lbs saved, but then again if LS7, LSA and LS9 can handle the stock output plus what other have done to pump up the output. It might not be too much of a valid reason to go LSx...

But its your choice for a piece of mind.. go with the LSx... you can always go bigger with it later...

just another 2 cents.

BC

LSxChevelle

iTrader: (4)

I just don't hear many good things about the LSx block. Like bczee said, look at the stock LS9 at 640hp and room for lots more safely. The blocks are safe. The weight savings are just an extra bonus.

highboost2000

I will deff be following this thread and build,,I just drool when I see those things and the LSX376 is made just for something like that. Good Luck with the project..

LSX Fan

I've heard rumors about the LSX block too, but no one has come forward with real facts. I can't imagine why any of it would be valid. I mean unless Chevy has some bad manufacturing going on, there's nothing about an LSX that would cause a problem.

The material is there for great strength, the engineering is great, the same people that built the LS7 and LS9 are the ones that designed and built the LSX! So why do peeps say bad things about it...especially when no one has proof?

But I do agree that the LS9 can handle the power, but also know how we car guys are...let's be real...I go and get used to driving an 800hp Ultima and what do I do next?? I want more!!! With an LS9 I'm already pushing the limits...with an LSX I'm just getting started.

And if you think an Ultima can't handle more...then you just don't know much about the Ultima GTR!! Case in point:

The Black Falcon http://www.youtube.com/watch?v=aAVagNqaT7I