I have a 1996 Corvette LT4 with all the free mods like coolant bypass air box cut out and relay line relocator.Also Flowermast exhaust with high flow cats. Oh alos a air foil. I have 3:73 gears on the rear end. So I wish to make some more hp and i dont know what my next step is to get the increase i hope. I would lve to get to the 400hp range or even so the 450hp area. What do you think is the next step in getting more hp?

 

You might be able to get 400 rwhp with heads and cam. Your car probably has 300 to 315 rwhp now. If you need more power then this you will need to rebuild bottom end 383 etc. Another option nitrous, or some type of forced induction. Eportworks is in Texas, guys name is Lloyd or people I used www.advancedinduction.com

 

My LT4 car put down 305 rwhp in completely stock condition with 103K. I have since added a delteq and a K&N filter.

I would invest in some Long tube headers from EM or TpiS since you already have cat-back, you'll see some gains in hp. I would also invest in throttle body, either 52mm or 58mm depending on what your H/C plans are.

I figure with full intake and exhaust you'll be around 330ish rwhp. Then I would invest in a either a N20 bottle and a tune, or go the N/A route and order one of Lloyd's custom H/C setups.

His setups are usually good for around 400hp N/A.

Then you could buy the bottle and be at 500hp.

 

I agree with all of the above....Heads , Cam , Long tube Headers , Throttle body , Adjustable fuel pressure regulator and a tune.
Then give it the laughing gas .

 

Oh I left out the part about having a 58mm throttle body also.I wen to the track and was running 8.6s in the 1/8th for 2 runs in a row at 84mph then i got a good run but let off to early and speed was only at 78mph and still ran 8.45 sec. So does anyone think i could hit like 8.20s?

 

I just looked at my time slips and I have a LT1 with only 365 rwhp and my best 1/8 time was 8.035 at 88.41 mph. With 400rwhp you will be in the 7s for sure. You should talk to Jonescap here on the forum. He has a 96 LT4 running low 12s with around 330 rwhp which is awesome.

 

the guy with the lt4 running low 12's is jonecap(chris).
an electric waterpump will free up some usable power.long tubes may help a little but i think you would pick up more power from a cam and/or head porting.then the long tubes would be useful.from here on out nothing is cheap.i also think you wold run quicker with a stock 48mm throttle body at this level.your part throttle response would be snappier anyway(i put a 52mm on mine and switched back to the 48,it is more responsive).

 

The LT4 intake is ported from the factory for a 52mm TB, I couldn't tell a big difference but it seems to flow much better than the stock casting, just by the look of it. There is so much more room to move air in the BBK. My throttle response didn't changed much, but the car felt stronger. I do not like the way the throttle linkage feels though, not nearly as smooth as stock.

 

Guess I need to get more serious and do more motor work rather than just bolt on stuff.What about the LT4 hot cam kit?Mine is a CE LT4 but i think it has a smaller came then te hot cam kit does.They say it will make my car produce 425hp so thats like 340whp or something. I wish i could get it tuned but I cant find anyone close. The nearest guy who does it is in Oklahoma. Like i said i also have 3:73 gears also so i dont know how much that helped me out bc i never drove one with the stock gears which i think are 3:45.What about an X pipe bc I dont have that?

 

I installed the Hot Cam, installed new valve springs, did some light porting on the heads, had a 5 angle valve job done, port matched the intake to the heads completely (there's a lot of material to take out to do this) and wound up with 344 RWHP through the completely stock exhaust with a tune. Nothing else was changed.

That's getting close to 400CHP right there.

It made 323 RWHP before the tune on a Dynojet, Bryan from PCMforless managed to get another 21 HP at the wheels with just tuning. That's impressive if you ask me! This was done on the dyno though so your results may vary.

I probably wouldn't recommend port matching the intake to the heads unless you're prepared to go much further in time. You're torque will suffer just a bit meaning it will remain almost unchanged. Mine made 316RWT, not bad but nothing to write home about. Definitely send the heads off for porting but limit it at that if you're not sure about future plans. The LT4 heads can make some serious power when done right.

This spring I will be adding EM 1 3\4 primary long tubes with high flow cats and probably going with a different grind cam to take advantage of the better breathing with the headers. I may have more head work done, not sure at this point.

Then install 4.10 gears.

Oh yeah, forget the free mods, to make big gains it takes big money and big time. 400CHP is easy, after that it ALMOST takes bigger cubes.

 

I believe the LT4's had a X-pipe stock. I can't say for sure since my car was modded before I bought it.

I say if your going to go to all the trouble of putting a cam in, put in a cam bigger than the hot cam. Yes, its a good cam, but there are bigger cams out there the would do more for you. I'd also say get some head work done when you swap cams, and a cam spec'd to you head numbers. Later on you can step up to a 383 or a 396 for even more power.

An electric water pump will help you put more power to the ground, as will an under drive pulley. Unfortunately there aren't really any for the LT4. I have an 10% under drive ATI super dampner pulley on mine with an electric water pump.

Long tubes are also good too.

I don't know how often the have it, but you should see about going to one of the meetings at the Sargents in Arlington on Friday nights. I know it would be a long ways from where you are. It's been a while since I've been, but I hope to start going again soon. That way you could see and hear other vettes and what they have done to their cars.

Where did you run the 8.45 at? Redline?

 

Redline is a nice track but it takes to long to get a time bc the line is long. I got my times at the Sanger track(denton dragway). It was hott to bc my car was like at 220 degrees but yeah still fun though. Yeah I will look into that thing in Arlington thanks. Thanks

 

An electric water pump will add a few extra horsepower. I could definitely feel it after I installed mine and ultimately the car ran 4 tenths and 2 mph faster in the quarter mile with just the addition of the water pump. However, the air temperature was about 20 degrees cooler, which is probably where most of the gain came from.

After EM headers, high flow cats, electric water pump, free mods, and a tune, I'm at 329 rwhp. I expect the car should run consistent 12.20's next trip to the track with an 11 second timeslip possible...I'm hoping anyway

I recommend doing the exhaust work (headers) before a cam install. Look at it as building blocks. You've got to get the basics done first before you go for the big stuff. Probably the biggest performance gain you can make on an LT4 car is 4.10 gears

 

Well i have 3:73 gears do you think it will be that much of a gain to put 4:10s in it?

 

Call Lingenfelter and be prepared to write a fat check.

 

The stock Lt4 exhaust has an H pipe after the resonator.

 

I think if I already had 4.10 gears I wouldn't go to the trouble and expense to install 4.10s. Spend you $$ on other items. Good luck!

 

Theres a tuner in the area. Call Scott at A&S in Keller. He tuned mine and alot of other LTx cars. Heres the website. http://www.asautomotive.com/

jeff

 

Thanks alot

 

Just curious I have a LT4 in my 64 Corvette GS, hot cam, custom side exit headers into 3 1/2" side pipes with a maxium flowing 2 1/2" flow through inserts, pcm for less OBE 1 programed computer. Any ideas what I might be looking at in HP? Its running but not on the road yet.

Any thoughts about what kind of gains I might see getting the heads ported or changing to AFR's? Thanks