300 hp L98?
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,160
Likes: 3
From: Greensboro NC
300 hp L98?
I just bought an 87 vert w/24,000 original miles. Are there any bolt on mods to get a little more spunk out of the engine. What options do I have short of major heart surgery to get as close to 300 HP at the wheels.
PS, No I don't want to spray it. No I won't spend 10 kajillion dollars (and make it undriveable to walmart) to turbo or supercharge it. And no I don't have a machine shop in my basement to fab anything. Sorry for the rant but I'm new to C4's and computer controlled engines and reading all the posts it seems like I need 3 laptops, 4 dyno's and a degree from MIT to make this thing just a bit quicker (see user name).
PS, No I don't want to spray it. No I won't spend 10 kajillion dollars (and make it undriveable to walmart) to turbo or supercharge it. And no I don't have a machine shop in my basement to fab anything. Sorry for the rant but I'm new to C4's and computer controlled engines and reading all the posts it seems like I need 3 laptops, 4 dyno's and a degree from MIT to make this thing just a bit quicker (see user name).
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
I just bought an 87 vert w/24,000 original miles. Are there any bolt on mods to get a little more spunk out of the engine. What options do I have short of major heart surgery to get as close to 300 HP at the wheels.
PS, No I don't want to spray it. No I won't spend 10 kajillion dollars (and make it undriveable to walmart) to turbo or supercharge it. And no I don't have a machine shop in my basement to fab anything. Sorry for the rant but I'm new to C4's and computer controlled engines and reading all the posts it seems like I need 3 laptops, 4 dyno's and a degree from MIT to make this thing just a bit quicker (see user name).
PS, No I don't want to spray it. No I won't spend 10 kajillion dollars (and make it undriveable to walmart) to turbo or supercharge it. And no I don't have a machine shop in my basement to fab anything. Sorry for the rant but I'm new to C4's and computer controlled engines and reading all the posts it seems like I need 3 laptops, 4 dyno's and a degree from MIT to make this thing just a bit quicker (see user name).
Or feel faster?
If you are looking for seat of the pants accelleration, 2800 stall, 9.5 inch converter, and 3:73 gears will make it feel much quicker.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
It's possible, tpi will be a major restriction though.. personally I'd start with some long tubes and a new exhaust system from there back. Do you want to keep the tpi system? That will be your worst enemy..
Last edited by 86GoldProject; Nov 1, 2008 at 08:10 PM.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
You're aware that 350hp rating was gross hp and not wheel hp correct? If you are looking for 300hp at the flywheel that's a bit easier.. Also that L46 probably had much better gearing which made it feel faster also.. Pete's suggestion is a very good one, you will probably be much happier.
Last edited by 86GoldProject; Nov 1, 2008 at 08:15 PM.
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,160
Likes: 3
From: Greensboro NC
What if I ditch the computer entirely, remove the TPI and put a carb on it and tune it the way I'm used to meaning cam, advance possibly higher compression? Is that doable? I mean its just an aluminum headed 350 right?
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,160
Likes: 3
From: Greensboro NC
You're aware that 350hp rating was gross hp and not wheel hp correct? If you are looking for 300hp at the flywheel that's a bit easier.. Also that L46 probably had much better gearing which made it feel faster also.. Pete's suggestion is a very good one, you will probably be much happier.
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Higher compression would mean a piston swap, head swap, or stroke change to the bottom end. 100 ways to skin this cat.
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Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,160
Likes: 3
From: Greensboro NC
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
Thats what I did, except I dropped in an already carbed 350 I built since I got my car with no engine. But yet it's just a regular old 350 with aluminum heads and fuel injection on it. The amount of power you want is only limited to your budget. With a good dual plane intake, a good carb, vaccum advance dist, and a cam swap 300+ hp is extremely easy to acheive. The factory exhaust system is pretty restrictive so that should be addressed as well. If you wanted more you could always do a head swap or port the factory castings.. it's all about what you are looking for.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
people throw superchargers on L98's all the time. It's one of the easiest ways to overcome the restriction of the intake since you are forcing air through it instead of letting it suck in what it can.
Le Mans Master
Joined: Mar 2006
Posts: 5,262
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From: E. Amherst NY
Don't go carb though.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
Right, don't go carb unless you want power cheap and easy tuneability. Sure gas mileage will suffer slightly but not that much, you will also need a lockup kit to keep the torque converter lockup function working, or you could wire it to a toggle switch and control lockup manually. Lots of guys on here are quick to say don't go carb, its a step back in technology, fuel mileage suffers, blah blah blah. It's all about what you want out of the car, also take into account if it will need to pass a visual inspection, it will most likely fail with a carb unless the inspector is clueless. Personally if it were my daily driver I'd keep the TPI setup, if it's going to be a track/weekend fun car I'd throw a carb on it and never look back. Obviously both carbs and fuel injection can make big power, carbs just do it cheaper.
Le Mans Master
Joined: Mar 2006
Posts: 5,262
Likes: 0
From: E. Amherst NY
Right, don't go carb unless you want power cheap and easy tuneability. Sure gas mileage will suffer slightly but not that much, you will also need a lockup kit to keep the torque converter lockup function working, or you could wire it to a toggle switch and control lockup manually. Lots of guys on here are quick to say don't go carb, its a step back in technology, fuel mileage suffers, blah blah blah. It's all about what you want out of the car, also take into account if it will need to pass a visual inspection, it will most likely fail with a carb unless the inspector is clueless. Personally if it were my daily driver I'd keep the TPI setup, if it's going to be a track/weekend fun car I'd throw a carb on it and never look back. Obviously both carbs and fuel injection can make big power, carbs just do it cheaper.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
As far as superchargers go the most popular ones as far as L98's are concerned seem to be the vortech and the procharger, both of which can make good power, but on a stock engine you want to keep the boost levels low. Keep in mind any serious modification you do will require tuneing via a custom chip if you keep the fuel injection setup. For a ton of good technical information on tpi cars visit www.thirdgen.org the technical information and knowledge of the members of that site far surpasses anything you will find on here.
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,160
Likes: 3
From: Greensboro NC
You can install different runners and a different manifold. Throw on some 1.6 roller rockers and long tube headers. Oh, and a cut lid/K&N combo for good measure. That'll definitely give you more seat of the pants. All without really requiring a tune.
Don't go carb though.
Don't go carb though.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
sorry I just think 14 second cars are somewhat boring. Not saying that all injected cars are slow, however most tpi cars are. I personally just don't have the money to invest in making a tuned port car fast, some guys do, I'm just not one of them. Believe me, if I had the money I'd go that route, but my car isn't my daily driver so gas mileage is of little concern, getting to the end of the track is.
Le Mans Master
Joined: Mar 2006
Posts: 5,262
Likes: 0
From: E. Amherst NY
The Hedman Elites are a good deal at ~$400.
Pro
Joined: Feb 2005
Posts: 560
Likes: 0
From: Hamilton New Jersey
If you want to keep a pretty stock tpi setup you can go with the edelbrock base (accel,tpis, they are all made by edelbrock now so go with the cheapest), SLP runners are quite popular but there are a few others out there. Along with those you may want to ad an adjustable fuel pressure regulator as these cars seem to like a little boost in pressure. With the runners, base, and regulator I'd also recommend taking the time to port your plenium, if you've ever seen the inside of a TPI plenium gm left a lot of room for improvement, its just that the base is the main restriction so it's the logical place to start.
Last edited by 86GoldProject; Nov 1, 2008 at 08:58 PM.
Thread Starter
Burning Brakes
Joined: Aug 2001
Posts: 1,160
Likes: 3
From: Greensboro NC
Chris the 87 doesnt use an electronic trans. Do I still need to make it lock up to work with the carb setup? I agree with you. Its a weekend fun car and 230HP in a 3500 lb car aint a whole lotta fun. (except like 0-40 mph)