EFI SBC vs LS Motor

[WSSix]

Originally Posted by redefined

Thanks for the response.

However, I'm not sure about your 'lag' description. Superchargers are far more linear than a turbo is, am I missing something here? Is it the that style supercharger, a Procharger that's not as linear?

I've own supercharged and turbocharged vehicles, mostly BMW's and the supercharger on that one was far more linear and constant than the turbo. On a road course you better know exactly when that turbo will spool or you'll be going sideways.

Correct me where I'm wrong! Thanks!

Yes, it's because it's a Pro-Charger. They need RPMs to build boost just liek a turbo typically does. A Whipple, Magnacharger/Harrop/Eaton, and Kenny Bell blower won't act like that typically(the wrong cam or too big of a blower can cause some lag though). They are known as positive displacement blowers. They are listed in a volumetric size because that's the equivalent "displacement" they add to a motor. Basically, they make the motor act as if it's bigger than it really is from the throttle response to how much power they end up making. However, a Pro-Charger makes great power and is an excellent supercharger. It's just not making power where or how it needs to be made in order to make a good pt style car. That's my point, be careful where and how you make your power when reaching for that 700whp goal. That's why I think you'll need to plan your build from the get go if 700 is the goal. Last thing you'll want is a 700whp motor that is no fun to drive the way you want or intend to drive.

500-600 is much easier to build in stages starting with NA because it's fairly easy to reach those numbers reliably with low boost levels. 700 at the wheels puts you at about 850 flywheel. Going from NA to that level boosted reliably is not so easy due to the increase in boost needed among other things. This is of course my opinion. I'd highly recommend you work with a builder before you do anything if seriously reaching for the 700whp mark. I'd also recommend you focus more on how you want the engine to respond and where the power is made than simply shooting for a number if enjoying the drive is the main goal.

A car for you to check out that may be of interest is one built by member RS302 or something like that. He started with a 1st gen that was Ford 302 powered. Once he blew that motor, he went to an LSx with twins. The throttle response is unreal on that car. I love it. He makes great power and runs it on 87 octane. It's a neat build.

[GregWeld]

There's just no comparison between a SBC and an LS motor.... if you're looking for a great "up grade" from what you have now - just buy an LS motor or be sorry you wasted your money on old skool stuff. You'll be money ahead with the LS.



The HP figures you're throwing around require a LOT more expense than just the motor. I won't waste my time explaining this now - cause you're not there... but anyone on here will tell you this.

[redefined]

Thanks for the info guys, didn't know that about the ProCharger, good to know!


It sounds like I might end up going turbo after all. Those other style chargers introduce a decent amount of heat/soak issues due to their placement for the style driving I do, sounds great for 1/4 mile though but I don't do that except for fun with friends. I'm for sure not chasing any 1/4 numbers though I'd much rather spend my time on the street and road courses.

Sounds like for what I want I do just need to go ahead with an LSX style swap and well my built 350/tranny.

Good info! I'll look more into the comparison of procharger vs turbo setup now.

I've very familiar with what would need to be done to the motor, especially for the type of driving and power, but had no clue of that ProCharger and the way it reacts. We'll see if I decide to built the motor or not for whatever I decide. After this research I'd been thinking of doing everything else, other than the motor, first. Mini-tubs, front and rear subframes etc. Decisions decisions!!

Thanks!

[GregWeld]

That "heat soak" issue you mention certainly hasn't played out in the last few Corvettes and Cadillacs that are running factory roots style blowers.

Originally Posted by redefined

Thanks for the info guys, didn't know that about the ProCharger, good to know!


It sounds like I might end up going turbo after all. Those other style chargers introduce a decent amount of heat/soak issues due to their placement for the style driving I do, sounds great for 1/4 mile though but I don't do that except for fun with friends. I'm for sure not chasing any 1/4 numbers though I'd much rather spend my time on the street and road courses.

Sounds like for what I want I do just need to go ahead with an LSX style swap and well my built 350/tranny.

Good info! I'll look more into the comparison of procharger vs turbo setup now.

I've very familiar with what would need to be done to the motor, especially for the type of driving and power, but had no clue of that ProCharger and the way it reacts. We'll see if I decide to built the motor or not for whatever I decide. After this research I'd been thinking of doing everything else, other than the motor, first. Mini-tubs, front and rear subframes etc. Decisions decisions!!

Thanks!

[redefined]

Originally Posted by GregWeld

That "heat soak" issue you mention certainly hasn't played out in the last few Corvettes and Cadillacs that are running factory roots style blowers.

For road courses or 20-30min track sessions? Is this the new LS9 motor you're talking about?

[GregWeld]

Originally Posted by redefined

For road courses or 20-30min track sessions? Is this the new LS9 motor you're talking about?

LS9 or LSA -- either one.

[redefined]

Originally Posted by GregWeld

LS9 or LSA -- either one.

Ya, won't be going with one of those motors though heh

[uxojerry]

At 500fwhp it would be cheaper to do a 383 rotating assy, port the heads/intake and buy a FAST 2.0.

At 700rwhp you need to go LS, and be prepared to spend some money. Another option for 700rwhp is a BBC.

[redefined]

Originally Posted by uxojerry

At 500fwhp it would be cheaper to do a 383 rotating assy, port the heads/intake and buy a FAST 2.0.

At 700rwhp you need to go LS, and be prepared to spend some money. Another option for 700rwhp is a BBC.

While a BBC is sexy sounding I'm not sure I want the weight. If I do swap the motor I'll 100% go fuel injection too.

[TheJDMan]

I agree a BBC would be too heavy. The real issue is which EFI system. Holley, FAST, MSD, who makes the best throttle body EFI? They all just keep getting better.