khalid

Hello every body, i am new to this forum, i just got my vette 1994 coupe LT1,
i bought it with some mods instaled , flowmaster exshaust, vortex air intake,and hypertech power programmer, i have instaled some more parts to it , 58mm bbk throttlebody, granatelli MAF, hooker headers 1 3/4",accel coil.
i did not notice any change in performance as if all these bolt ons were waste of money? i do not know if the 58mm TB did not match with the intake ? or this is as much as i can get from the LT1 boltons?
i have ordered the GM lt4 hot cam kit hat include the .525" int/exh lift cam and special springs and 1.6 roller reckers, i hope that will improve my lt1 performance ? i also need to know about the rear end ratio as i have the lowest ever made! 2.59!! i need to know what would be the best relacement for it 3.73 or 3.54?
i know i have loaded you with questions but i am hopping that you guys can help me hiting 400hp out of my engine . all the best. :blueangel:

JB666

I think a lot may agree right now that the 58MM TB , and MAF weren't anything you'll feel as the stock units are enough for a considerable amount of HP. I put a 52MM TB on a couple weeks ago, just to have for this coming winter's mods..
Did you drive this car much before you started tearing it apart?? Sounds like you weren't happy with it's performance from the get-go?
Also, did you put long tubes on or shorties??
3.73's would be a GREAT gear swap for that.. I've got a 6spd and am considering the 4.10's this year.

:cheers:

G-Racer

Get the most out of that cam and any other mods by having your heads ported. That is where the real HP is to be gained. Thirty HP is a conservative est. Give me a call if I can help

Greg Parker
Steadfast Performance
Cylinder Head Specialist
Engine Blueprinting
703.609.1200

dizwiz24

Hmmmm. Id think with the intake/exhaust mods you did you'd feel something (or at least think you do)....Also, if you replaced your stock exhaust manifold with shortie headers instead of long tube headers, you probably wont get any improvement either.

I am wondering can the 58mm throttle body hurting performance? (Ive heard it doesnt help. With my ported head/hot cam/long tube headers/custom chip I felt an immediate improvement (Esp. on high end) the first day I drove it

Yeah, I dont know. Did you run it at the track 1/4 mile before and after?

Get rid of the 2.59's but dont go too high. Also, be wary of auto people talking you into higher (youll have to do the math of whats too high, after your rear gear changes) stall torque converters. If its too high, you'll be slipping at highway speeds (burning up your trans, bad gas mileage, etc.)

Finally. An automatic will run a faster time (but lower MPH, however time wins it) 1/4 mile run than a ZF6. Keep in mind the advantage you have outta the hole!

vader86

You shouldve felt some difference with the headers, so I dont think you wasted all your money.

Get some 3.73s if you really want to feel some power, then save for a 2600 stall Torque Converter, before buying a hotcam kit. You'll feel like you got your money's worth after these two.

Remove the hypercrap's power settings, just leave the shift points and fan settings intact. It could be the hypercraps timing that causes you to not feel much.

FD2BLK

Try re-installing the stock TB and see if you notice a diference. You have way to big of a TB for a basicly stock motor, even with the hot-cam the stock TB would be plenty. I have a 52 with the hotcam, Long tubes and ported heads and am considering going back to the stock TB (Its just a better TB then the BBK). The headers should give you some good HP gains but you may need a dyno to see it or a very well tuned butt-o-meter.

Lone Ranger

:iagree:

Too large of a Throttle Body can cause a loss of torque. No reason to go larger than 52mm unless you are running forced induction (super charger or turbo).

tjwong

When you ordered your HOT CAM kit you should have ordered the complete LT4 conversion kit that gives you a set of LT4 heads and an LT4 intake. If you have a head porter there have him port those heads for some added performance :)

Realistically what you have done should have given you some noticeable gains. The only thing I see that is a little on the "iffy" side is the GMS MAF. Normally I never replace the stock MAF unless its a supercharged engine that actually outflows the stock unit. I tell this to everyone because the PCM is calibrated to the stock MAF. And who knows what the GMS MAF is calibrated to. It could be way off causing the PCM to skew its fuel trims to maintain correct fueling. In other words it can possibly hurt performance! Just as gutting a stock MAF could possibly change calibration as well.

With your A4 trans 3.54 gears are adequate. If you want a little better acceleration a set of 3.73 gears are even better, but it will sacrifice a bit of top end. So it depends on your driving habits, want more straight line acceleration properties go for the 3.73 more top end go for the 3.54 gears.

Also a 58mm TB really isn't necessary on a near stock engine. Most of the time a 52mm TB is adequate. Just think of this, GM uses the same 48mm TB on their 502 RAMJET fuel injected big block crate motor that makes over 510Hp with that TB :) So if its OK to feed a 502 its definitely OK to feed a 350 small block :)

When you do the LT4 cam to get the most performance out of that conversion you should have your PCM custom programmed for the new cam. Then you will really see the difference or rather feel it :)


[Modified by tjwong, 8:50 AM 5/3/2004]

khalid

Hello again, this forum is great !! i am very glad for the support from all of you guys, thx.
I agree with all of you that the 58mm throttle body is too big and maybe also the MAF is not matching the hypertech calipration, i will reinstall the stock TB,and MAF, and reprogram the car with the hypertech again, and will let you know thw result,

i am also planning for a supercharger, any recomendation ? :blueangel:

Lone Ranger

Just know that the Hypertech Power Tuning does not work well on LT1 and LT4 engines.

I think ATI ProCharger is the only super charger for the LT1 that fits direct from the kit without modification, but to be sure ask over in our C4 Forced Induction and Nitrous forum.

94 Octane

Hmmm...that's not what I have heard/read on this forum. My understanding is the Hypertech works well with the LT1.


Anyway I will be able to confirm this in a couple of days.


I just received the Hypertech III and will be re-programming the speedo after a 3.73 upgrade from 2.59. The 3.73 made a HUGH difference and I love it!

I will do the higher octane program since I only run Sunoco 94 octane, and let you know the results.


:seeya

corvette1990

Hello: just some more advice for you. Your engine is a big air pump, that is fueled by gas pushing pistons. If you read the advertisements, you would believe that every modification sold raises your horsepower. Many lie about there claims. In A matched package they may all add up to more HP. Having alot of air in with larger MAF , and letting alot of air out by headers, and less restrictive mufflers, was a good start to increasing air flow. BUT, unfortunately, like has been mentioned, the intake manifold chokes the air down, as well as the cylinder heads (with smaller valves). You will notice many people making larger horse power have switched to better breathing heads or have had there stock heads redone, with larger valves/springs and porting of the passages to let more air through. The CAM is the brain of the engine, but can only work the valves it has to work with. The computer is the brain of the fuel injection and timing of the firing of the spark (along with distributor. Before you spend any more money, look into getting a matched set of parts that work together. See beach bums proven setups if it still works. http://temp.corvetteforum.net/c4/bea.../ProvenSet-ups or for supercharegs look at: http://www.procharger.com/dealers.shtml or http://www.tpis.com/CatalogPages/CatalogPage.asp Good Luck

TA

:iagree: I bet the 58mm TB is hurting your potential gains :yesnod:

Mad-Mic

i agree with what most said. swap the stock TB back in. Hypertech is ok but it's idiot proof. you won't gain too much but it's nice to be able to playwith shift points. if you really want to make more power take it to someone that can tune with LT1 Edit. average HP on a stock motor is around 20 rwhp.

i disagree with the gear change especially if you drag race the car once and or plan to put a higher stall converter in. don't waste your money on rear gears if you plan on modding it for straight line performance. it WILL break on a hard launch and not only break but you'll be buying a new center section with a new set of gears to go along with it.

a few bolt on's and get it tuned and you should see 12's pretty easily. when you do a stall converter get the car dynoed and see where your max torque is and get a stall that is 400 rpm below max torque and you'll still be happy with your 2.59 gears. i pull 1.80 60' times on mine with my ole 87 vette with a handful of bolt ons. from a 2.59 gear set to a 3.54 gear set your only looking at about .5 in overall ET gain. to me that isn't worth it especially if you build the car to run like it should. like you said you want a supercharger well that Dana 36 wont handle it :smash:

Lone Ranger

Nope. The overall opinion on the forum is and has been that the power tuning feature of the HPP3 and HPP+ is basically worthless and the GM tuning is better. There have been members dyno test and lose around 4 or 5hp or tq using the Hypertech power tuning. Now, having said that, the unit is handy for speedo changes to accomodate gears/tires, and for setting the radiator fans to come on at lower-than-stock coolant temps, plus for A4 cars the Hypertech shift firmness seems to work as advertised. But not their power tuning. All hypertech does in their power tuning is make stab-in-the-dark changes to the Power Enrichment tables in the PCM and small relatively useless adjustments to the spark advance timing tables in the PCM. I have examined a hypertech'd PCM image in comparison to a stock one using Tunercat software and observed these things. The main reason some guys seem to feel a little more 'pep' right after programming with the hypertech is that it zero's out the PCM's learned fuel trim (BLM) and the PCM is in relearn mode for the next 20 miles or so, and running off hard coded fuel tables during that time as it re-learns optimum fuel trims based on oxygen sensor feedback and MAP readings. A rich mixture (inherent result of running off the fuel tables vs. oxy sensor feeback...) is generally better for low end torque, so the car may feel slightly 'snappier' at first right after programming.




[Modified by Lone Ranger, 10:07 PM 5/3/2004]

94 Octane

No kidding. So are you saying I shouldn't use the Hypertech power programming and leave that portion stock?

1996man

you never answered what style headers you are running. shorty or long tube? as mentioned before, shortys will make it sound meaner but wont give you enough of a gain to really feel. what else do you have exhaustwise? cats? mufflers? resonator? what have you done to these? they all play a part.

Chevy Guy

All the mods in the world wont help if they arent "needed". Simply bolting on an exhaust or opening up the intake wont really help if your engine cant take advantage of the added flow. Manufacturers reported gains are always best condition "estimates" and rarely (if ever) a reading of gains on an actual car they were intedned to be bolted on.

As an example, way back when I had a 90 Formula Firebird, I put a high flow exhaust, Air filter, chip, and went from 2.73 to 3.23 gears in the rear.

The end result..........A slower car.

Yup,.. I was like WTF??? The way I figure it the exhaust killed the low end torque to the point that the gears and chip just about made up for it. How do I know it was slower? I was gettting my butt handed to me by a friend whos car I used just barely beat. It sounded faster, I thought it felt faster, but I was sadly mistaken. Real world results dont lie.


[Modified by Chevy Guy, 5:16 PM 5/4/2004]

Nathan Plemons

If you want to waste TON of money you would do it this way. You can get a Hot Cam for $180. The "LT4 Conversion" costs you $2000+ For about $800 less than the cost of the LT4 Conversion you can have your stock LT1 heads ported which will flow more than enough air for the hot cam. Ported LT1 heads will easily stomp a set of stock LT4 heads and cost a lot less. If you get LT4 heads you'll have to spend another $1200 to have them CNC'd and ported, which might give you 5-10 hp over the LT1 heads so long as you're still using the Hot Cam.

Don't get me wrong, the LT4 heads are the only way to go for ultimate power, but the Hot Cam won't take advantage of it. $2000+ worth of extra cost doesn't justify 5 hp.

khalid

Sorry about that, i have the hooker shorty ceramic coated headers, and the flowmaster full exhaust system,plus i had the cats removed for less restrection. :blueangel: