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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?

-TJ

Well I would say yes, but I am biased because I would like to see you out there running with us. We do have a very good group running now. Me , Andy, Bill{he bought Larry Bakers old 98 1LE and former National champ) and a few Mustang guys that are getting very fast. So just do it.

With all the money you're making you might want to take a look at the grassroots $2008 challenge! It isn't the most serious game out there, but you'll get in a magazine and have a few laughs.

Then they'll get claimed.....

Yeah, the local ESP field is very fast and competative, it really would help my driving to have a challenge like that. And it'd probably be a good change for me to be 50-100RWHP down instead of 50-100RWHP up on everybody. Or I could be like Scott Fraser and drive a Miata to get faster...


...naaaaaaaaaaaaaaah.



Hmm, that's a thought I hadn't had yet. Though I'm not sure exactly how they do the accounting. I mean, when I tell them I got a very clean '97 Z28 for -$2000 (assuming I sell the TA for a decent price) I think they'd send me packing. If they allowed it though that'd give me $4008 to mod under the $2008 rule. Hehe.

-TJ

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.

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.


SCCA got those results up fast. Actually I hadn't even left the site yet at the time of Jeff's post. I just got home from the DC Pro and my car is still on the trailer with all the stuff in the truck. I'm hoping I get motivated to take the car off the trailer tonight, but the AC in the house is so nice after all the heat and sun we got today.

Yes.

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???

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.



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.



Interesting to know.



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

In ESP, yes.

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

Take those 1.6 rockers out. That'll help. Ran them in my car for a while with a CAI and u/d pulley and it sucked. More HP at the very top and it was a dog everywhere else. Really fell flat on the bottom. I didn't have programming at the time, but bone stock my car was over 300lb ft from under 2k rpm to over 4K with a peak of ~315. Was on a dynojet, fwiw, and was when the car was in f-stock trim and had a crappy crossflow flowmaster.

The others have pretty much taken care of you but I thought I'd add my own thoughts....

My car with only a cat back exhaust and CAI put down 267 hp / 305 tq on a dynojet. This was at 97K miles with the factory original cat converters, stock manifolds, factory original Opti and stock tune. I don't have a problem believing that 300+ ESP legal rwhp is very attainable in an LT1.

They are heavier to be sure, but it's more on the order of 50 - 60 lbs at most. In any event, my '96 weighs almost exactly the same as my brother's '99.

Yup and you'll wonder why you didn't do it sooner.

without question.

Sell both cars, track down Sam, buy my old car, and swap in a 93 trans.

LT1's have more potential to be light than an LS1 car. The LS1 'may' be lighter but not necessarily. I've yet to see proof with my own two eyes. The cars are basically exactly the same. Which tells me IF the LS1 is lighter then the change in bodywork makes up for that.

That car I sold had MAD, MAD, MAD torque. I think Phil and Brian remember in Oscoda a couple years back how bad my wheel hop was off the line, and I'd still pull 1.9 60's. Rolling into the throttle and "launching" at idle. The tune, or something made it peter out big time past 5500 but man would it pull down low.

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...

Yeah if Lonnie's old car is around for sale, buy that. Especially if it's for sale anywhere close to what Lonnie sold it for.

Pat

You can't really do a whole lot inside the engine. Anything outside the engine is pretty open (intake manifold, headers, etc). The SCCA rulebook can be downloaded for free from scca.com.

Pat

Heck, Pat, I wish I had your old car for anywhere close to what you sold it for I didn't have the cash then, and don't now, but it's on my "why didn't I" list.

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

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 Not that you'll be able to use all of it.

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.

Did you mean the LT1 valvesprings? I am pretty sure my LS1 doesn't float the valves at 5200, although it might, just not a noticible amount?

I know you have very intricate knowledge of ICE. Would changing to some new stiffer pushrods and LS6 springs be a good idea for my DD w/ 127K mi on it?

I am kinda worried about the valve springs getting tired and I mechanically over-revved my car once, but never checked to see if the pushrods were all still straight(never a ticking sound, happened 35K mi ago)....

Oh, i'm well aware that auto-x is not all about power. To that end, yes, an LT1 can be very comptetative. Heck, there's a guy up here running ESP in an '86 IROC that kicks everyone's tail. I'm more interested in getting as much power as possible to have fun during it's daily driver duties and still play with the ESP cars on auto-x days. But yeah, there's no way i'm spending that money for the little gains you're talking about doing as long as the motor is running.

My LS1 doesn't feel like it loses much at 5200. It pulls pretty well up to 6k when it taps the limiter.

I'm sure he meant LT1 valve springs because my LS1 make peak HP @ 5700 rpm and only lost 3hp from peak @ 6,000 rpm.

Thanks for the advice! I'm leaning more and more towards building this car, so now I'm starting to look into the budget it'd take to get it competitive. Here's what I'm working with...

• '97 Z28
• Six Speed
• Hardtop
• Crank Windows Etc
• ~100k Miles
• A lot of fresh parts (clutch, u-joints, water pump, this and that sensor, oil pan gasket, intake gasket, etc)
• 18x11 & 18x12 CCW Classics (from Z06) w/ 315/30-18 & 335/30-18 A6s

So I'm thinking I need at least the follwoing to get in the ballpark of competitive:

• Good Diff (what's working these days? T2R, ???)
• Ground Control Setup in the Front (probably somewhere around 800-900#)
• "Weight Jacker" Setup in the Rear (probably around 300#)
• Shocks (I'm up in the air here, pretty much nothing off the shelf would work well w/ the spring rates I have in mind, maybe just have Strano valve some Bilsteins for me?)
• Sways: Strano Bars
• Brakes: LS1 Front Upgrade w/ HP+, SS Lines, Fresh Stock stuff in the Rear, Adj. Proportioning Valve
• APHR: Build my own AL/Heim
• Lower/Level APHR

To get the car to the top level of competition (even though I probably won't be there as a driver yet):

• Motor Work: The motor is healhty, but I'd need a CAI (actually might have one from another car), LTs + True Duals, Under-Drive Pullies, Roller Rockers, and a good Tune to get competative. If/when the motor dies a full LT4 build would be the way to go.
• '93 Trans
• UETA
• ????

-TJ

Most (but not all) 4th gen ESP cars run a T2R (there are a few other not-as-good options).

Most (but not all) 4th gen ESP cars usually run a 500 - 600 lb spring in the front and 150s in the rear, But if you're going to mess with the PHR, then yeah, I guess you'll have to run it stiffer. FWIW since we're talking about being nationally competitive here, I'd hate to experience what a "stiff" car would feel like at HPT. I ran there on a warm day in May and my "soft" car never felt like it got hold of the surface. I'd think that the stiffer cars would really skate around there on a cold day in late September. *shrug*

I have absolutely no problems with wheelhop under braking with a comparable setup to your list. The adjustable prop valve would be an unnecessary waste of time IMHO.

Roller rockers are not legal for an LT1 in ESP trim.

An LT4 build would have to *exactly* reproduce an LT4 right down to the smallest detail.

Hmm, I guess I hadn't considered the surface @ HPT. I'm spoiled with Castle Airforce Base out here. I'm still a long way off from specin' my spring rates, but it doesn't hurt to start researching now. I had 500 or 550s (don't remember off the top of my head) in my '99 Z/28 and they were certainly too soft for the surfaces out here.

As for the Rockers thanks for the heads up. It looks like I need to read the rule book again.

What all is involved in "exactly" reproducing a LT4? I have access to a true LT4 block/heads/intake if the internals are only modded to the ESP rules would that be enough?

-TJ

You would need a complete, factory LT4. There are a lot of little details about the LT4 that are over-looked.

http://www.grandsportregistry.com/lt1vslt4.htm


Also, do anyone know if the f-body LT4's were 2 bolt or 4 bolt mains?

I've asked around and the consensus from those who've torn them apart is that they are 4-bolt, identical to the 'vette motors internally.

I've gotten as far as an estimate for the cost of building one , then I got skrrrd. Engine builder swears he can get crank HP numbers that start with a "4" though

So this would be fully legal, correct: http://www.sdparts.com/product/12534776/19...vroletYLT4.aspx

Also, would a LS1 (and LS1-era T56) swap be legal in a '97?

-TJ

Well, here's a problem that I see...

GM no longer has the intake in production. Good luck finding one.

I believe so but why would you want an LS1 vintage trans?

I already have the manifold lined up, besides aren't intake manifolds unrestricted?



Sorry if my wording was confusing. I meant to swap in a LS1 motor + the appropriate trans for the LS1 (since as far as I've seen there is no legal way to run '93 gearing behind a LS1 due to the different input shafts).

-TJ

Yes, but I'm not sure how that would play into an engine swap. I *think* since the rulebook reads that any swap must be done as a unit, you would be required to use the LT4 manifold. Besides, is there an aftermarket intake that will fit the LT4? The new Edelbrock might. I don't know.

I don't know if a modified LT1 intake would work since there are some restrictions on porting as well.

You can put on any intake manifold you want.

What he said. You can do whatever you want to the intake. Port it, use an aftermarket LT4 intake, or even a carb'ed LT4 intake if you really want to.

Edelbrock does make an LT4 Airgap; some guys on LS1Tech actually have one.

LS1 swap into a 97 would be a complete waste of time and money. As we've been over the LT1 IS competitive. Regardless of dyno numbers the LT1 has more torque. Especially an ESP LT1.

I'm not even sure that an LS1 would fit into the bodywork of an LT1 car.

If I were to swap in an LS1 to build an ESP car it would be into a 93 or 94 hardtop V6 car with no options.

What is the issue with the car? Ive been looking for a stripper Z for a good amount of time, and they are hard to find.....



Looking to sell it?