LT4 motors still have a smog pump but no EGR. All my emissions are still hooked up. As for the DRM headers (Doug Rippie Motorsports) They no longer make the C4 ones.

 

RichS,
How much did the 4.10's help? I still ave the 3.45's in the car. I just got a set of Dana 44 Viper gears in the mail last Wednesday, I plan on installing them later this winter when it gets colder & starts snowing. :)

 

I had Hooker shortie headers when my LT4 was still stock. I wouldn't recommend them. If you are gonna do the mods you have listed, I would opt for longtubes. The shorties did very little over the stock manifols. The longer tube length of a full length design greatly inceases the amount of air that can be pumped through your motor and you will also benefit from the scavanging capabilities longtubes give you. Check out this link for a really good article about headers and the importance of design. Also, Speed Works (listed in the tuner links on this page) of Lewisville, Texas can do a super job reprogramming your computer.
:thumbs: http://www.ssheaders.com/header.htm

 

I see on the DRM site they sell, this header. Sig, do you think this will work?
1992-96 LT1/LT4 Corvette
35-145
$950
(The LT1 and LT5 full-length headers are fabricated from stainless steel and are custom built to fit the Corvette chassis. Each header’s pipe size and length has been chosen, after years of on-track and dyno experience, to maximize torque and horsepower on their respective engines. These headers maintain oxygen sensor hook-ups and air tubes, and will mate to competition, Borla, Flowmaster or stock exhaust systems. The factory catalytic converters will not mate to these headers, making them illegal for street driving. An increase of 25 horsepower can be expected when fitted to one of DRM’s for-racetrack-use-only converted engines.)
Are these the same you have? Or are they just as good?

 

Rippie lists them but won't sell em' anymore. I called & got very near begging for the stainless 1-3/4" I had the cash. They wouldn't sell. Referred me to Exotic Muscle who I hear makes a very nice set of headers. Don't quote me on this but I remember reading a post recently that said Exotic Muscle was having a sale on them also, something like $450 w/ceramic coating.

 

I would have the ECM programmed on the dyno. http://www.thunderracing.com looks to be close to you or use one of the Texas shops, MTI, or Speed Demon come to mind. Speed Demon and Thunder have always treated me well :yesnod: I have never used MTI. If you do not have smog tests go with a bigger cam than the LT4 Hot and a set of Hookers with no cats for the most power. MTI has some great ported heads. Thunder and Speed Demon use Gallant (GTP) heads who has a great reputation for big numbers.


[Modified by 93Polo, 6:56 PM 12/1/2002]

 

I put the 4:10s the weekend I bought the car. (Did Corsa, B&M, 4:10s, Vortex that weekend) The gears do make a great 1st mod on a M6. I had them in my 95 LT1 M6 car also. When I drove the GS home it felt like a dog with the 3:45s and stock motor compaired to my 95. The gears make a big differance, and don't kill the MPG on the highway, I still ahve no problem doing 150 either :D

 

MrCrowley,

you make reference to the LS1 being able to use 1.8:1 rr's. that is correct. The factory ratio is up there, too... like 1.65:1 or something stupid.

However, the LS1 is so different from the LT1, that the only thing they share is bore center.

comparing the LS1 to an LT1 is like comparing the Chevy 302 to a Ford 302. Sure, they are both 302's, but thats where the comparison ends.

 

I was just wondering if anyone has tried 1.8's on a lt4 that was all. But back to what more concerns I have is this: So what would be next comparison in headers to the DRM's that are no longer available. Sig, whats the next best choice in full length headers? And what was the part numbers on the Random Tech. cats you used. Or is it better to just do away with the cats. Brake tags are a gimmie where I live.

 

The only 1.8 rockers I know out for a LT4 would be a shaft system that would cost big $. I would go for the Hooker headers but the TPIS, DRM, and Exotic Muscle are great headers.

 

RichS, I think you should change your name to Sig., what do you think? :lol:

 

Mr. Crowley, Sig is not RichS' name. You know that picture you made as your avatar? That's your sig. He is asking you to refer back to his sig. to read about his modifications and his times in the 1/4. :cheers:


[Modified by zelement, 11:28 PM 12/1/2002]

 

Welcome and good luck. Your LT4 has an electric smog pump - no need to eliminate unless you don't ever need to pass an emissions inspection. I haven't seen anyone use 1.7s on a SBC, so I'd stay with proven successes. You can get a ton of power with the right cam and 1.6s. If you do the ram-air, watch out for water. With the head, intake, and cam work is done, best results will come from a tuner who can program your ECM hands on. The Hypertech is great for changing you speedo after doing 4.10s and for getting the fans to turn on earlier, not much more.

Maybe an abvious question, but what do you intend to do with the car? Drags, autocross, road courses, or just street driving? I'd suggest taking a close look at the rules for classes under each sancitoning body that you may plan to do some form of racing in before making any mods. You want to end up in a class where you will be competitive if that's your direction. It is way too easy to mod youself into a non-competitive position. If racing ventures, other than drags, are your goal, suspension work and seat time will pay far greater dividends than mods. The LT4 Vette is a strong platform for a starting point and for many racing venues, its power is quite adequate already, so learning to "drive" may be time well spent while you decide what your goals are. Then, modify to improve your competitiveness in the class you want to be in. Just my $.02 worth.

 

As long as you are changing flywheels I would use the aluminum single mass rather than the steel SM. Herb Adams in his book Chassis Enginering calculates the improvement in acceleration for removing sprung weight, versus unsprung rotating weight that rotates at axle rpm, versus weight that rotates at engine rpm. In his example with a 5:1 rear axle ratio in a 3000 lb car, putting out 300 ft-lb, removing engine rotating weight is 15 times as important as sprung weight. Removing unsprung axle rpm weight is only 3 times as important as sprung weight. Because you will not use this same axle ratio as his example your improvement might only be 12 to 1 ??compared to sprung weight removal, but even still I think well worth changing to an aluminum SM flywheel. So if the aluminum flywheel saves you 20 pounds ??, this would be roughly equivalent to 20x12=240 lbs of sprung weight removal in terms of your increased acceleration.
FrankLT4CE :thumbs:

 

After trying the single mass flywheel in my Dad's car I can't recommend it. We never picked up anything in ET or 1/4 MPH. In fact it made it harder to launch the car -- too little RPM and the car would bog, too much and the wheels would spin. Not too mention that dreaded rattle that you get with single mass...

The LT4 motor can be made quick with very few mods. My Dad's car went a 12.33 with just a hot cam, 4.10 gears and drag radials (stock exhaust manifolds and stock PCM). Next step up would be to duplicate RichS's car. It's a strong runner with minimal mods too.

 

Here's $.02 on the clutch aspect. I'm told by a very well regarded C4 technician that the best pick is the L88 16 pound steel flywheel mated with the stock LT4 disc/pressure plate.
He said to drop the heavy dual mass unit and to avoid most of the aftermarket discs ... especially the "puck" designs because they tend to chatter badly in drag racing applications. Cire96