LT4 Improvements
1st Gear
Joined: Sep 2011
Posts: 1
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To the original poster: About the underdrive pulley - first off be sure its the combo balancer and pulley for a 'Vette and not the separate F-body pulley only. Also, the LT4 balancer is tuned differently than the LT1 unit so there could be some vibration issues using it. I believe GM set the redline on the LT4 based more on saving the accessories so doing an underdrive may pay off for extended high RPM all out running, but on the street once the fans, lights, radio, and WP are going the slight gain may not be worth it. Either way install it with a light coat of anti-seize and it's not that big a deal to swap. My $.02 on 4:10 gears is this - If you run drags, esp 1/8th mile with sticky rubber I think they are worth it. On the street traction could become an issue. GM spent big $$ and time setting the trans and rearend ratios for optimal performance, and loosing time making more shifts may actually result in a slower time. Consider too, 4:10s will run a fair amount hotter (diff oil temp) which could be an issue for extended high speed. My biggest bang for the buck mod was the aluminum flywheel - hard to beat shaving off over 30 pounds of rotating mass BUUUUTTT there is the neutral / low RPM gear clatter. For me it was worth the performance gain...
Thread Starter
Instructor
Joined: Mar 2011
Posts: 169
Likes: 0
Well, everything is just about done. Just have to put the headers on and button her up. Came across another snag though....Tuning. All of the shops I'm calling say they can't do an LT4. This is going to be a serious problem if I can't find a shop that can.
Safety Car
Joined: Dec 2009
Posts: 4,363
Likes: 430
From: Birmingham Al
elliottsportwork.com Look him up out of Dallas Tx..nice guy and will tell you what you can get out of the LT-4 ..He won't just try to sell you something you don't need ..Bolts ons don't help much on the LT- motors ..Need to build the motor from ground up to get big power..Stock with heads and cam Ect. 450 rwhp about max. 383 biger 500-550 max ..I have boltons on mine LT-4 with retune 325 rwhp no cats bigger TP K&N 8.5 wires few other things ..Runs way better that stock but no 400 hp comeing out of a few boltons... Stock LT-4 heads a little cleaned up is all you can do to them almost maxed out at stock . The heads cleaned up will make 450Hp with cam Ect... maybe up to 550???
Thread Starter
Instructor
Joined: Mar 2011
Posts: 169
Likes: 0
elliottsportwork.com Look him up out of Dallas Tx..nice guy and will tell you what you can get out of the LT-4 ..He won't just try to sell you something you don't need ..Bolts ons don't help much on the LT- motors ..Need to build the motor from ground up to get big power..Stock with heads and cam Ect. 450 rwhp about max. 383 biger 500-550 max ..I have boltons on mine LT-4 with retune 325 rwhp no cats bigger TP K&N 8.5 wires few other things ..Runs way better that stock but no 400 hp comeing out of a few boltons... Stock LT-4 heads a little cleaned up is all you can do to them almost maxed out at stock . The heads cleaned up will make 450Hp with cam Ect... maybe up to 550???
I'll give your guy a call if I can't track down Scott. Thanks for the info!
Safety Car
Joined: Dec 2009
Posts: 4,363
Likes: 430
From: Birmingham Al
I have the LT4 hotcam, electric water pump, OBX headers with magnaflow catback, 52 mm tbody, and a complete professionally worked set of stock heads and intake. My heads flow 272 cfm at .500 lift. I'm anticipating (hoping) for about 375 RWHP with a good custom tune.
I'll give your guy a call if I can't track down Scott. Thanks for the info!
I'll give your guy a call if I can't track down Scott. Thanks for the info!
Safety Car
Joined: Dec 2009
Posts: 4,363
Likes: 430
From: Birmingham Al
I am thinking about building my 96 LT-4 this winter ..It has 140,000 miles and I don't think it can take any more power (Boom)I think I better build the bottom end.. I am thinking about the LE-2 ( that's from the guy in Dallas Tx. setup about 375 rwhp LT-4 ported heads and cam driveable or might go 383 50 -75 more rwhp should be about all the C-4 can stand I drive on the track and I think that's all the even a modfied Sup. can take..I think you can over power the C-4 ..From what I here from other people 370-400 rwhp is still streeable if build right won't be no 500-650 hp like in a C-5 or 6 but will be fun ..I can run with most C-5s now..Saying you got 700hp doesn't mean you can drive it...I know people that have 600-700 hp in the newer ones way over powered..You have to be Jr.or Jimmie J.to drive the thing...
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Thread Starter
Instructor
Joined: Mar 2011
Posts: 169
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Well, everything is semi-done. Still needs a tune, plus I'm trying to track down a knock. I've only driven it in short jaunts and it feels superb. Oh, and I had a helluva issue with an exhaust leak.
Hopefully I'll have the tune done within the next couple of weeks and then get some track runs in.
Hopefully I'll have the tune done within the next couple of weeks and then get some track runs in.
Thread Starter
Instructor
Joined: Mar 2011
Posts: 169
Likes: 0
Update: Shortly after getting everything put back together, the car spun a rod bearing. Luckily, it happened at idle so there was no collateral damage involved. I've been too distraught, aggrivated, pissed off, bummed out, etc....to mess with it since.
Well, I'm back on it now and have thought that maybe I'll go ahead and do the 383 afterall. Any suggestions/reccomendations on which way to go?
Well, I'm back on it now and have thought that maybe I'll go ahead and do the 383 afterall. Any suggestions/reccomendations on which way to go?
