Is the horsepower at the flywheel of the tires? I could live with that horsepower at the rear wheels.

 

Yesterday 06:33 PM
snowmanmdp
Quote:
Originally Posted by black85 View Post


What? There must be something wrong with your car don't you think? You have the cat removed, long tube headers and a 2.5" exhaust? You are only getting a 14.5 sec run?

Like I said, I was a 13.7 w/o the headers, which was the biggest gain I got from any single component (except getting rid of my clogged up cat). I think if I were to get drag radials I would drop a couple more tenths. Just wanted to share my experience. There are many on here that have similar mods running similar times.

 

My car has the air foil , smooth air inlet, K&N air filter,underdrive pulleys and axle back 3 inch magnaflows. If there is something wrong I can't find it! It burns no oil or leaks nothing, plugs look fine car runs fine, just no instant power! Now don't get me wrong I would race just about anything in a 5 mile down the freeway race! The car is a monster from 50 to about 120 mph, the problem is getting to 50

 

That sounds more like an LT1 than an L98. The torque you put out should get you to 50 in no time as long as the wheels don't spin excessively. If you have an auto try a 24-2600 stall converter, they keep the car very streetable.

 

This is at the tires. I havent ran it at the track yet but I will once it re-opens down here. Its being rebuilt. Ill say the car is pretty fun to drive!

 

What are you using the car for? If it is 95% street driving, low end torque is what you want. HP is for the track.

TORQUE= gets the car moving. More torque, faster move.

HP= sustains movement.

My '89 Formula 350 had AS&M runners, ACCEL manifold, both ported and matched, 52mm TB, 1 3/4 SLP headers, 2500 non-lock stall, and every free mod you can think of and it pulled 232 RWHP/341 RWTQ.

The L98 with a long runner cannot move enough volume of air due to the extreme length of the runners at high RPM.

 

Well.... from what I'm hearing this motor is not going to do much unless I switch over to a carb or put a blower on it! I'll have it from there, if that is what I do. I have a handle on the whole carb thing ,everyone says fuel injection is easier but you could not prove it by me!

 

No carb is needed to make any number.

 

You are missing the point. The motor needs a head, cam, intake and exhaust work to make 350hp. Notice the dyno posted -- from someone with a mild cam and vortec heads. 300hp is what he got with both. I've seen alum head 350's run low 13's with a larger intake and ported heads (only). But, alum heads flow better.

I think it's a toss-up whether heads or cam provide the best improvement on their own. Either would help, both are needed for your goal of 350hp. And, 350hp should get you into the 12's.

Because you're not running fast until 50mph, it sounds like you need gears (and I didn't see what you're running now). Based on your desired to get better street performance, having gears at least 3.54should be an early step.

Putting on a carb won't get the heads to breath better. You need more air before considering more fuel. A blower wouldn't hurt, but things are fairly bottled up in a stock motor.

 

I know for a fact, even though I switched to a carb, my heads are holding my cam back a lot. A better intake wouldn't hurt either, but I need more overall cfm. Carbs create more problems than they solve, bud.

Stick it out and get those heads ported, you'll notice more oomph even if you just do them alone. More s with a cam, and even more with gears and an intake port.

 

It could be that your just used to quicker cars. I put a big block in my 91' and it is just about right for me now on the acceleration scale but I am still not quite happy with the "snap". It freaks out most that ride in it though.
Greg is right about the gears, that will give you seat of the pants but be ready to run out of motor quick.

 

WOW.....your stock 85 is WAY FASTER than mine was in stock trim.....like a full second or more...those rwhp/tq numbers on the chassis dyno indicate significant modifications for an 85 L98....

 

Putting on a carb won't get the heads to breath better. You need more air before considering more fuel. A blower wouldn't hurt, but things are fairly bottled up in a stock motor.[/QUOTE]

I'm not missing the point:o you guys are saying more air to make more power, I understand...a motor is just an air pump, but if I can't flow the air through the runners what is the point of having better heads? Like I said I can live with 300 horsepower at the wheels, which is what he has. I think a gear might be a start at this point, As far as big block...well there is a 815 Sonney sitting in the corner at the race shop that they keep trying to get me to put in the vette Keep the ideas coming as the more I read the more I'm learning about these cars.

 

You could be right It's the snap, there is none :o I'm like you I want to take friends for a ride and them having that look of terror on their face when the get out.

 

I would stick with fuel injection. You could get your car into the 12's easily with bolt ons. I was talking to someone on another thread that has the same torque and hp peak numbers as me and his best was 12.85. His name was Razor.

If the intake is what you are worried about then take a look at the mini ram. That thing can breath pretty darn good.

 

The factory quarter mile time for an '85 is 14.1 sec. I thought. Is your car stick? I don't know why that would matter, but my car leaves the line like a rocket. It pulls 1.8 60', but it falls off up in the high rpms.

There has got to be something going on w/ your car. I have been wondering where the big difference could be all day. I should check my build sheet though. I thought I had 2:73 gears, but I have all the z-51 options except the lower gear ratio (and the actual z-51 rpo).

I bought it from my father in law who rarely drove it (bought it in 1987) who bought it from a 70 year old man who drove 70,000 miles in just 2 years. I seriously don't think any motor mods were done. I never did anything to the motor itself but put on fancy valve covers.

Maybe your cat is a little clogged. I just never heard anyone say a tpi was slow up to 50 MPH before! Check everything, particularly your tps adjustment to make sure you are getting the 4.5 or 5 volts (whatever it is) at WOT. Check the base timing, fuel pressure, everything. If my car started going in the 14.xx's I would know something was really wrong. And I have at least 60 passes on the car.

 

the 52mm TB is a waste of money. i back to back tested one against stock one day at the track and didn't pick up anything in ET or MPH. spend that money on a cam. just make sure you stay within the limits of the wimpy vortech springs. if it were my money i'd toss the heavy vortech heads and buy the edelbrock e-tec 170s. they are a far superior vortech style head.

 

Vader Rules!

 

Stock manifold and runners flow over 185cfm. It's their length/size that cut them off above 4,500rpm -- kindof a harmonics thing. But, you said that was O.K. -- because you want low-rpm power. The TPI will get you that. With better heads, you could just go with bigger runners (and the same base) if you didn't need more than 300hp. Ported 113's are a good example of that. You could get intake flow into low 200's (cfm) and that would match a bowl-job on the 113's. Add a bigger base (to the runners) to get past 230 cfm. This is in the full-porting range of the 113's. A lot of aftermarker heads are in this range too. Swapping a cam will change how air flows thru those heads and how/where your car makes power. But, I'm getting off-track.

I'm not familiar with the flow #'s from your year, but I know they flow less than my alum 113's which are about 175cfm. I'm going to guess your iron heads flow considerably less than 185cfm -- probably 25% less. This means your intake's not the problem yet.

Your exhaust and your heads are more of a restriction than the intake. I'm also betting you have mileage (vs performance) gears too. If so, they won't help with low-end torque (leverage). Do you know what their ratio is? Do you know how to find out?

Do some serious reading on performance mods here (and in thirdgen). You'll come away knowing a bunch more.

 

113s will flow around 195cfm @ .500 on the intake stock. 225cfm isn't hard to get with better valves and a home port job. i experimented on a set before i bought my pro actions.