[tjZ28]

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So that brings me back to my actual question: can a LT1 Fbody be Nationally Competitive in ESP?

Let’s face it even with every ESP legal motor mod a LT1 is only going to do maybe 275RWHP. LS1 cars are doing 290-320 RWHP STOCK and with the full array of ESP legal motor mods can put down probably 350RWHP. I’ve heard of a few ESP cars that claim 400RWHP ESP legal, but frankly I don’t buy that (I’ve been around the LS1 community a long time and outside of this particular car/driver’s claim I’ve never seen a bolt-on LS1 make those kind of numbers).

On top of that a LT1 car is probably an extra 100lbs nose-heavy.

So, what do you all think: Can a LT1 still be Nationally Competitive in ESP, obviously excluding the driver issue? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif)

-TJ

This post has been edited by tjZ28: Apr 21 2008, 08:36 PM

[tjZ28]

Is the car already too modded for F-Stock? If not, FS is way cheaper to run than ESP, and a very competitive class. And since all FS f-bods are forced to stick with the stock 16x8 rims, the extra 50hp isn't helping the LS1's that much. LT1 cars are competive in f-stock. Hell, 3rd gens are still winning National Tours, so it's anybodies game. And after checking the results from this weekend's prosolo in DC where an LT1 car finished 2nd in ESP, I'd say they're competitive in ESP too.

The car is stock right now, so I could easily go FStock with it. However, I'd really rather not go from a 450RWHP Z06 w/ a good susp. setup, great brakes, 315 front/335 rear Hoosier A6s etc. "down" to a stock 4th Gen. Fbody on 245s or 265s. Also, I don't think there's a lot of top-notch competition locally in FStock. In ESP I can look forward to getting beat down by some National level drivers... and I think that really could help my driving progress.

Yes LT1's are very competitive. The LS1 cars make more peak Hp, but it's from about 5300-6000 rpm. There are not many courses that you get to rev that high in 2nd and even when you do it's for a very short time. So all the extra hp means nothing if you don't spend a lot of time in that rev range. As far as SCCA classing the LT1 in ESP can use the 93 trans which has deeper gearing then all the other years. So the LT1 actually has an advantage that the LS1 cars can't get because the 93 trans won't bolt up behind an LS1 in ESP legal ways.

The series I run the most getting to the top of 2nd is very common actually. Besides, I've always argued that the whole "LT1s make more low end power" thing is just an urban legend. If you look at a (stock, or similarly modded) LT1 graph vs. LS1 graph clearly the LS1 makes more power up top. But really they make just as much power down low... they just don't run out of breath so they keep building more power past ~5k rpm where the LT1s start to level off. My '99 Z28 dynoed 300/310 RWHP/RWTQ stock. I don't think there's a lot of stock LT1s doing more than 310 RWTQ and I didn't even have a '01+ with the better intake etc.

But I think you're right, the '93 trans gearing could make up pretty much all of the difference.

And after checking the results from this weekend's prosolo in DC where an LT1 car finished 2nd in ESP, I'd say they're competitive in ESP too.

Interesting to know.

Yes. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/cool2.gif)

The trans makes a big difference and I was not losing a thing in the first 200' at the prosolo this weekend to the LS1 cars I launched against. I don't buy that an LT1 car is 100lbs heavier than an LS1 car on the nose. My car made 265hp at the wheels stock, and I know I've picked up tons from the y-pipe, bolt-ons, and Jeff Creech tune. There's more to be had, but Sam has hopped in my car and out run his times in his two-time national championship car. So is more power going to be better or just different???

I don't have the #s in front of me, but the Iron LT1 block is a lot heavier than the AL LS1 block. Further the LS1 has the much lighter composite intake manifold. Is it exactly 100lbs? Probably not, but I think it's pretty close.

I do appreciate the input though, it sounds like LT1 cars can be competative.

Oh, and it is legal to update to LS1 front brakes, correct?

-TJ

This post has been edited by tjZ28: Jun 26 2007, 04:55 AM

[SStrokerAce]

I've always argued that the whole "LT1s make more low end power" thing is just an urban legend. If you look at a (stock, or similarly modded) LT1 graph vs. LS1 graph clearly the LS1 makes more power up top. But really they make just as much power down low... they just don't run out of breath so they keep building more power past ~5k rpm where the LT1s start to level off.

Yep I have two dyno charts of a stock LS1 car here and a lightly modded LT1 car (Programing, 1.6's, Springs, CAI, Shorty Headers) and they are almost identical in the low end, the LS1 just builds TQ quicker and to a higher amount. The LS1 cars will nose over at 5200rpm with stock valve springs in there.

FWIW I have a customer with a LS1 car, stock untouched heads, new springs and pushrods, LS6 intake headers and a mail order tune PLUS a 9" and he put down 350rwhp+ with that. A LS motor with attention to detail and some TLC built legally to ESP rules could easily make over 400rwhp, a LT couldn't do that in a long shot. A standard CAI, Tuning, Headers LT car can do 300, 320rwhp at the most. Maybe 350-360 with a motor that was built to a T within the rules.

Bret

[wdtiger]

FWIW I have a customer with a LS1 car, stock untouched heads, new springs and pushrods, LS6 intake headers and a mail order tune PLUS a 9" and he put down 350rwhp+ with that. A LS motor with attention to detail and some TLC built legally to ESP rules could easily make over 400rwhp, a LT couldn't do that in a long shot. A standard CAI, Tuning, Headers LT car can do 300, 320rwhp at the most. Maybe 350-360 with a motor that was built to a T within the rules.

This i'm curious about. What all can be done within ESP rules? I know lid, headers, cat back. I guess i never really read the rules much as far as engine mods were concerned...

[pknowles]

FWIW I have a customer with a LS1 car, stock untouched heads, new springs and pushrods, LS6 intake headers and a mail order tune PLUS a 9" and he put down 350rwhp+ with that. A LS motor with attention to detail and some TLC built legally to ESP rules could easily make over 400rwhp, a LT couldn't do that in a long shot. A standard CAI, Tuning, Headers LT car can do 300, 320rwhp at the most. Maybe 350-360 with a motor that was built to a T within the rules.

This i'm curious about. What all can be done within ESP rules? I know lid, headers, cat back. I guess i never really read the rules much as far as engine mods were concerned...

I think if you take advantage of the rebuild allowances in the rulebook you can pick up some more HP. Your allowed to bore to .0472" to gain a about 8 more cubies, mill the heads to max GM spec or .010" (whichever is greater) to up the compression ratio, port match the intake and heads within the first inch of the head, find the lightest factory pistons and rods, match heavy rod to lightest piston, etc. You can defiantly make more power using all these allowances, but it's a lot of money for those last few HP and torque numbers. It only makes a difference if your at full throttle and how much time do you spend at full throttle autocrossing? The really fast guys don't seem to spend much time at all at full throttle at less in Fbodies. I think this is much more important on a real race track were you do spend a lot of time with your foot to the floor. If I popped my factory motor I would probably take advantage of some of these things to make more power while I was in there, but I just can't see dumping $4-6k (total guess, maybe more) for 10-15ish HP (another guess and it might be less). Depends on how much that last .100 of a second is worth to you.

Autocrossing for the most part is not a power game on most courses, not that more power can't help. The fact that a CSP Miata is usually a second or less behind an ASP Z06 indicates to me that it's not a power game as much as a suspension and tire game, IMHO of course.

[BigEnos]

FWIW I have a customer with a LS1 car, stock untouched heads, new springs and pushrods, LS6 intake headers and a mail order tune PLUS a 9" and he put down 350rwhp+ with that. A LS motor with attention to detail and some TLC built legally to ESP rules could easily make over 400rwhp, a LT couldn't do that in a long shot. A standard CAI, Tuning, Headers LT car can do 300, 320rwhp at the most. Maybe 350-360 with a motor that was built to a T within the rules.

This i'm curious about. What all can be done within ESP rules? I know lid, headers, cat back. I guess i never really read the rules much as far as engine mods were concerned...

I think if you take advantage of the rebuild allowances in the rulebook you can pick up some more HP. Your allowed to bore to .0472" to gain a about 8 more cubies, mill the heads to max GM spec or .010" (whichever is greater) to up the compression ratio, port match the intake and heads within the first inch of the head, find the lightest factory pistons and rods, match heavy rod to lightest piston, etc. You can defiantly make more power using all these allowances, but it's a lot of money for those last few HP and torque numbers. It only makes a difference if your at full throttle and how much time do you spend at full throttle autocrossing? The really fast guys don't seem to spend much time at all at full throttle at less in Fbodies. I think this is much more important on a real race track were you do spend a lot of time with your foot to the floor. If I popped my factory motor I would probably take advantage of some of these things to make more power while I was in there, but I just can't see dumping $4-6k (total guess, maybe more) for 10-15ish HP (another guess and it might be less). Depends on how much that last .100 of a second is worth to you.

Autocrossing for the most part is not a power game on most courses, not that more power can't help. The fact that a CSP Miata is usually a second or less behind an ASP Z06 indicates to me that it's not a power game as much as a suspension and tire game, IMHO of course.

Don't forget about the Impala SS head gasket! Worth a little compression ratio (IMG:http://www.frrax.com/rrforum/style_emoticons/default/ph34r.gif)

You can also spend that $6K and build a from-scratch LT4. Then you'll have better trans ratios *and* way more power than an LS1 (IMG:http://www.frrax.com/rrforum/style_emoticons/default/nutkick.gif) Not that you'll be able to use all of it. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/rant2.gif)

Another thing I notice about autocrossing, with lots of courses with tons of transitions it becomes a "width" game. This is why Miatae and E36s excel more even than the sum of their parts. They just don't have to turn as much. We are solidly on the other end of that scale.