[tjZ28]

I'm under the impression you can legally swap a LS1 and the accompanying T56 into an older ('93-'97) 4th Gen Fbody for ESP. So, assuming that is correct what do you think would be the better combo?

* LT4 built to the limits of ESP rules + the '93 Trans gearing

or

* LS1 built to the limits of ESP rules + '98+ Trans gearing?

Let's assume this is in a '97 Hardtop Z28 built to the full limit of ESP rules also. The car generally would run on a large, fast, smooth, ultra-grippy concrete lot. BUT it would hopefully see Nationals in the next 2-3 years so it'd need to work on smaller, slippery surfaces too.

Running the numbers on 2nd gear only (since that’s where the car will spend at least 90% of it’s AutoX time) the ’93 Trans gearing would give about a 14% increase in RPM vs. the ‘94+. For example, if the ‘94+ gearing would have you at 3,000 RPM the ’93 would have you at 3,420 RPM.

I think it’s safe to say that the LT4 can match the LS1 on torque/hp until maybe 4500 or 5000 RPM. Only losing out a bit right up to ~6200-6300. But can a LS1 make as much torque/hp at 3,000 RPM as a LT4 could at 3,420 RPM?

Thoughts?

-TJ

PS- Yes, my head hurts too.

This post has been edited by tjZ28: Jul 11 2007, 12:53 AM

[LT4Firehawk]

No, the LS1 wasn't tuned, and while I'm sure you can get some improvement on an LS1, I honestly don't think it's going to be 36lb/ft gain on the low end. I was just trying to give a decent comparison of numbers, the LT4 cars came with LT1 ECM tuning, which significantly limited the HP, allowing for a way larger jump with proper tuning than you'll get tuning an LS1. I honestly don't think there's going to be enough difference between properly setup LT4/LS1, and the driver would make a much bigger difference. I personally just like the LT4 better than the LS1 after having owned both. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif) The bigger difference would be that you can run the 93 tranny with the LT4.

[sgarnett]

No, the LS1 wasn't tuned, and while I'm sure you can get some improvement on an LS1, I honestly don't think it's going to be 36lb/ft gain on the low end. I was just trying to give a decent comparison of numbers, the LT4 cars came with LT1 ECM tuning, which significantly limited the HP, allowing for a way larger jump with proper tuning than you'll get tuning an LS1. I honestly don't think there's going to be enough difference between properly setup LT4/LS1, and the driver would make a much bigger difference. I personally just like the LT4 better than the LS1 after having owned both. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif) The bigger difference would be that you can run the 93 tranny with the LT4.

There more room for improvement from tuning on the LS1 than you might think, at least with the later LS6 manifold. I found more torque all through the curve, but the biggest improvement was at the bottom end. You can't "tune" the 2.66 trans into a 2.97, though.