LT1-LT4 Modifications 1993-97 Gen II Small Block V8

L98 Performance Help

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Old 05-29-2007, 12:54 PM
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Originally Posted by Mike1234
Formula350... It's not that I want an LT1 so badly... just an economical route to my performance goals

So $600 for an LT1 intake and all machine work. Fifty bucks for a used stock '93 LT1 cam... that's GREAT news!!! Will the stock springs take the extra lift? BTW, I have a new set of Gen1 shaft-mount roller rockers... 1.6 ratio. Will this help? Can the springs take the '93 cam plus the 1.6 ratio rockers? This is $650-700 plus heads should I choose to upgrade... which is $1.4-1.5K... plus the ECU and other missing components, right? How much should I pay for the other missing components? I currently only have a bare short block and heads.

I'll work on replying to multiple replies within one post. My feeble mind is like swiss cheese these days
Trust me, the stock LT1 cam wont make ANY power over the stock L98 cam. the size difference is negligible at best. Having said that, a stock L98 cam will NEVER make 400rwhp unless you turbo or supercharge the engine. Period.

That setup i outlined above will make well over 400rwhp and will not break the bank. It can be done for less than 1500 if you know how to shop. The heads and intake alone can be had for a grand if you really know how to shop. A custom grind cam can be had for less than 400 bucks.

Think this stuff through long and hard. You will barely make over 300rwhp with a stock L98 or LT1 cam and stock heads. And you still have to buy springs and the same gaskets and all so the cost there kind of evens out. If you half *** this, you are going to regret it I bet.
Old 05-29-2007, 03:08 PM
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port the heads have 2.00 1.56 918 springs,7/16arp studs 1.6 roller rockers,LPE 219/219 560/560 you will have plenty power with this combo.
100% agreed with(1bdbrd)the 93lt1 cam is ablolutely not going to benefit your build at all!the only ones that benefit from an lt1 cam are the guys with TBI f-bodies and TBI trucks...
Old 05-29-2007, 03:20 PM
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Originally Posted by 96lt1m6
port the heads have 2.00 1.56 918 springs,7/16arp studs 1.6 roller rockers,LPE 219/219 560/560 you will have plenty power with this combo.
100% agreed with(1bdbrd)the 93lt1 cam is ablolutely not going to benefit your build at all!the only ones that benefit from an lt1 cam are the guys with TBI f-bodies and TBI trucks...
I was going to run my 219/219 LPE cam witha set of trick flow heads and was hoping for a little over 400rwhp and have a great power curve.

However, I disagree that he should port his heads. By the time he has ported the heads, bought new valves, machined the heads to fit bigger springs ect hes going to have just about the same as he would in a set of aftermarket heads that have much more potential later on.
Old 05-29-2007, 03:54 PM
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Originally Posted by 1bdbrd
Having said that, a stock L98 cam will NEVER make 400rwhp unless you turbo or supercharge the engine. Period.
And running the, marginally bigger (and yet still... bigger) LT1 cam + 150shot won't make even close? What do the stock LT1s + 150shot make? I bet it's close to it. I think he originally wanted 300hp, which is easily obtainable. 209hp to the rear with a 89-92 TPI, that's dyno proven stock performance. Make it 210 to be fair. 5 for TB Coolant bypass, 10 for free flowing exhaust, 15 if he can get even some shorty headers to fit in the Z, 5 24# SVO's, 8 for a bigger throttle body, 25+ for porting, another 5 just for using an LT1 cam (that's a fair gain), and then probabl 20 for an ECM tune. That's another 88hp so we're @ 323 flywheel, about 290 to the wheels. I think that's a pretty fair assumption for all the mods, and then add on 150shot. Wouldn't that give at least 400hp?

Yea, he'll need a 6AL + Window box $300, but that's not bad. Even if he can get stock shorty headers to work thats only $100 for them, $25-100 for used injectors, he can do the porting himself, cam is free from Astro, ECM isn't too much, and $100-200 for a 52mm TB off eBay (have a friend buy you it on their account lol). Even sending out the heads and intake for porting, another $400?
Old 05-29-2007, 07:33 PM
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if you take a look at Lingenfelters heads or even e-portworks heads they flow so well on these motors once they are massaged especially with the stock piston.take the same shortblock with a set of afr's that are fully worked and put them on without changing the cam do you think the car will run faster?
i really hope you did not say yes,cause without the cam and or compression change the larger head will lose velocity giving you a motor that runs like a TURD but on the bottle it will be sweet.Not saying looking to the future is a bad idea but all the componets need to match and compliment one another.
Old 05-29-2007, 09:12 PM
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He's getting the cam for free. I didn't say he's going to gain 60hp from it. I also didn't say he was going to get LE3 ported heads.

If your post wasn't aimed at me, NM
Old 05-30-2007, 12:49 PM
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383astro... I'll buy your cam, springs and the complete TPI setup. Please PM me with details!! Is this everything I need?

Formula350... [engine] Thanks for the advice. I'll do exactly as you suggest. Should I have any work done to the stock TPI or the Engine Management System? I've heard a lot about Megasquirt. Should I go that route?

[ebay] I tried opening a new account under a family member's name. I had gotten 50+ 100% feedback when they shut me down again... said it was because same last name and same address. I tried several more times to get help but... nothing.
Old 05-30-2007, 01:02 PM
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I think that is all you need. Maybe someone can chime in on this. I have the TPI intake with fuel rails and injectors, the computer, Wiring harness ( I think its the complete harness underdash and engine just missing the taillight harness?) and distributor. There could be some small misc that is missing I am not sure. I will be posting pics tonight. It is all out of a 88 Iroc Convertible. If you buy the TPI I will throw in all the LT1 cam valvetrain for free. Thanks
Old 05-30-2007, 01:22 PM
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1bdbrd... I know so little about any of the newer engines that I'm really driving in the dark down this road. I appreciate everyone here shedding some light on this for me!!!

I definitely don't want to half-*** this project but I don't mind compromising where appropriate. If there's truly 100 WHP difference between a stock setup costing ~$800 (parts, porting, gaskets, etc.) and ~$1500 for another 100 WHP/Torque... that's worth the extra $700.

96lt1m6... Thanks... the only thing different you suggest from 1bdbrd's post is keep the heads and have them reworked, right? Regarding nitrous... I'll use that very sparingly ($$$ka-ching$$$) so I want this motor to run really well when it's not on the juice too. Do you still suggest a rework of these heads?

Formula350... I'm sorry if I didn't state my goals clearly... I want all the HP/Torque I can get I'm not a wealthy guy and I'm open to all suggestions. I should make it clear that an extra 100 WHP is worth the extra $700 though my wait time increases in order to save the $$$. BTW, I already have a set of bluck huggers and a Crane hi-po ignition/coil and a window box.

ALL... Will a stock TPI setup be sufficient with the better heads... not half-***-ing it?

383astro... I'm not trying to be wishy-washy... just need to get this straight in my feeble mind.

Last edited by Mike1234; 05-30-2007 at 01:27 PM.
Old 05-30-2007, 03:16 PM
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please if you want a motor that wont fall on its face after 5000 rpm do not put a tpi intake on it, you will just be shooting yourself in the foot with a stock tpi intake

if you still wanted to go carbed get a decent intake manifold from edelbrock get the heads mildly ported i believe stock the heads flow about 190-200 cfm intake and around 150-165 cfm exhaust so you could have them mildly ported and have decently flowing heads, get the heads also machined for more lift and get a decent cam from comp or the like with the proper springs and what not

top it off with the 650 cfm carb good exhaust and you could easily have in excess of 350 hp that will rev a lot more freely to 5000 rpm plus and depending on the cam you picked out you could be in the 380-400 ft lbs of tq pretty easily

you really dont need the tq off idle you'd get from the tpi intake its going into a 2400 lbs car
Old 05-30-2007, 03:26 PM
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Well the TPI stops making power after 5500, the LT1 can do 6500, but in a car that weighs 2600lbs does he REALLY need that extra RPM? He's already got us all beat by 700-900lbs. If he used a T56 with 3.73s, there's be no stopping him, even with a TPI intake. I think most of you forget he's not making a drag car.

Mike, you don't need an engine management if you get the stock ECM.
Old 05-30-2007, 08:09 PM
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ALL... PLEASE... keep the info coming. I'm sorting through it the best I'm able. Regarding low-end torque... first of all I LOVE torque. Second... the stock converter I have doesn't cut it with the SBC currently in the car (350HP/Torque). I definitely need a 3000+ stall with this SBC. HOWEVER... it has a flat tappet cam. I know a well-matched roller is MUCH better.

BTW, this ol' Gen1 has a set of port-matched Edelbrock RPM heads. Will these fit the new L98?

I have another project that my old Gen1 will go into. I'm just offering this up for your consideration.
Old 05-30-2007, 08:21 PM
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Well, after browsing through GM Performance Catalog, how much you willing to spend?

Also, Gen1 started in 85!! Gen0 is anything before that. Hows that for interesting?

Using a stall really kills the daily driver ability. Sure you can, but you'll be shelling out cash for gas. I never plan on stalling any of my cars if I want to drive it alot. Track, thats a different story, and you need a stall then really. Except the one guy who doesn't, and still hits great 1/4 times and 60ft.
Old 05-30-2007, 09:22 PM
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Formula350... How much am I willing to spend? If I can get kick-A performance (400WHP/Torque) for $1500-1700 I'm in.

Gen1 started in '85. GEEZ... I AM old. I'm Gen0???

Mmm... I'm told that a stall converter "acts" quite naturally (like a standard converter) in a light 2400 pound car. Is this false?
Old 05-30-2007, 09:39 PM
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Ive got a couple of blowers or a 383 kit for sale also.

you said you like torque, My 383 stroker kit with the tpi and your heads should make pretty good, throw a blower on it and your looking at well over 400 tq.
Old 05-30-2007, 11:49 PM
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Originally Posted by 383astro
Ive got a couple of blowers or a 383 kit for sale also.

you said you like torque, My 383 stroker kit with the tpi and your heads should make pretty good, throw a blower on it and your looking at well over 400 tq.
That would be worthless just like all TPI setups. The TPI is worthless because it makes so much low end but it is useless at higher rpms where you actually are when you are racing.

Besides his car weighs less than 3k lbs so he doesn't need huge torque.
Old 05-31-2007, 12:06 AM
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Originally Posted by 1bdbrd
That would be worthless just like all TPI setups. The TPI is worthless because it makes so much low end but it is useless at higher rpms where you actually are when you are racing.

Besides his car weighs less than 3k lbs so he doesn't need huge torque.
Hey, he says he wants torque so I am trying to sell it to him.

I had a L98 car once that was dynoed making power up to 5600 RPM, not a lot of power but it was going up. It nosed over at 5800.

Also, if he can reach his goal of 400HP/400+TQ at 5000 RPM wouldnt that be better on the parts as a whole, less wear?
OR he could just put a bottle on it.
Old 05-31-2007, 03:19 AM
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Originally Posted by 1bdbrd
That would be worthless just like all TPI setups. The TPI is worthless because it makes so much low end but it is useless at higher rpms where you actually are when you are racing.

Besides his car weighs less than 3k lbs so he doesn't need huge torque.

I should've guessed, LT1 people talk **** about TPI, just like the LS1 and LT1.

Grow up, will ya? There is plenty you can do to the TPI setup that lets it rev higher and keep making power. Unless you're going to give him a great deal on a L98 ready LT1 intake with the distributor boss, then leave him be. I've ran TPI and LT1 and I love them both.

Mike, I asked how much you had, because GM offers the Ramjet kit for $1,300 and all you need then is the ECM and Harness. I don't know if you can use a TPI ECM and Harness, but if not thats another $700~ (500 ecm and 200 harness). The Ramjet is basically like the Holley and TPiS Rams, but uses a bit different TBody. Looks like a cross between an LT1 and TPiS Miniram. It comes with EVERYTHING you need too, intake, injectors, TB, air filter, rails etc etc etc.
Old 05-31-2007, 08:55 AM
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ALL... Thank you for your advice. Please keep it coming. I don't want to be the source of any arguements though. It sounds like there is an old brawl between types of induction systems. Like every other subject we all have our opinions and discussions can become heated. But again, please don't take anything too seriously in this thread. I'm just an ol' phart trying to get a grasp on newer technology so I can make my lil' ol' Z-Car haul azz.

Actually, I want the most HP/Torque I can afford and I want a nice broad power band that goes all the way up without becoming "peaky".

383astro... A blown 383 in a 2300 pound car would be scarey fun But I don't really want a supercharger. I'd like to keep this build simple so I can drive it everyday if I want.

Formula350... That GM piece sounds like a viable option... though $2K is really squeezing the ol' piggy bank. It may be awhile before I can afford it. I hate waiting but I hate regretting my mistrakes even more
Old 05-31-2007, 09:08 AM
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I wouldnt hesitate to drive a SC everyday, but thats me. I will still make you a killer deal on the TPI and 383 Kit if interested. I also have some 1.6 Rockers for sale to put a little more lift in that LT1 cam if you go that route.


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