I have a bone-stock L-98 in a 87 convertible that I would like to bolt-on some additional horsepower. I will start with a catback, but where from there?
Cold-air induction, chip, high-flow MAF sensor, airfoil, fuel press regulator? They all promise increased performance but my concern is which ones work together to produce the intended results? I would like to spend about a grand but no more than $1500. Thanks for your help.
Steve :chevy
It's an automatic, don't know the rear gears. Here in Nebraska we don't have any stinking regulations!! :cheers:


[Modified by sting ry, 9:05 PM 5/1/2003]

 

Not knowing the regulations in your state, I suggest...

Buy a pair of long tube headers and get a local shop to bend you a 2.5" dual exhaust with a crossover tube. You should add a set of 3-way high flow cats to remain legal.
Hedman headers: $109 Local exhaust w/o cats: $300 Coating headers: $200
**Note: If I were to do the exhaust over again, I'd buy the coated Hooker Supercomps with emission piping.


Cut a lager opening in your air box and add a stock size K&N air filter.
Cuting: free K&N: i don't remember


On the front of your water pump pully is a metal disk refered to as the "frisbee". Remove it. Take the belt off, there are 4 bolts holding it in, I used lock washers as spacers for the missing frisbee.
!Frisbee: free


Get the air pump eliminator kit. I got mine form Breathless.
BPP !air pump: $180


In the plenum behind the throttle body is a hump that restricts flow. Use a dremel and grind it down.
Grinding: free


Make sure your ingintion is in good working order. Replace the cap, rotor, and plugs if you haven't in the last year or so, wires should last a few years longer. If the coil and ignition module are original, you should think about replaceing those. I did at ~100k miles. Be careful because the plastic connectors are very brittle after years of heat.
Accel Ign. Module: $~70? Summit Racing coil: don't recall Tune up: $~35 Wires: ~$70?


Get an adjustable fuel pressure regulator to do a little WOT tuning.
AFPR: $70


I did all that on my 90 and gained almost 50 crank hp. the 90 does have a higher compression ratio and the heads are redesigned, but I'd imagine your results should be the same. Look in my signiture for anything I might have left out.

Edited to add some approximate prices



[Modified by Raistlin, 1:09 PM 5/1/2003]

 

Sting Ry,
Is your car auto or stick? Do you have 3.07 gears or 2.73's? (G44 option code on your RPO sheet is what you want)
I have an 87 Auto 3.07's, and here's a small list of the mods that I've done to run a best so far of 13.5@100mph (still more in it too!)
1.) Completely Cut Open your airbox = FREE
2.) Buy a K&N filter ~> http://store.summitracing.com/partde...NN%2D33%2D2014 = $55
3.) Remove your MAF Sensor and CAREFULLY cut out the screens = FREE
4.) Remove your Throttle Body and give it a GOOD cleaning with TB Cleaner = $5 for the can of cleaner
5.) Buy a Hypertech Power Coil Ignition Kit ~> http://store.summitracing.com/partde...art=HYP%2D4052 = $75
6.) Buy a set of MSD 8.5mm SuperConductor Wires ~> http://store.summitracing.com/partde...rt=MSD%2D31459 = $65
6a.) Buy a Accel HEI Ignition Module ~> http://store.summitracing.com/partde...rt=ACC%2D35363 = $50
7.) Throw in a new set of AC-Delco Rapidfire Spark Plugs = $20
8.) Buy a set of Hedman Headers #68447 = $275
9.) Have a local exhaust shop weld you up dual 2½" exhaust (if you need cats or not is up to your state) ~ $100
10.) While you're at the exhaust shop get a set of Hooker AeroChamber Mufflers put on (The mufflers are $60 each)
11.) If your car is auto, get a GM 2500rpm Stall Torque Converter (hopefully someone else can chime in with the part #, because I don't know it right off hand) = $250, (whether or not you need it PUT IN, is another story, usually costs about $200-$300 to have put in.)
So let's see, what's our Grand Total: Right at $1000. Trust me, after you do that list of mods, you will say DAMN! Your car will literally feel like a totally different car. :cheers:


[Modified by TIMSPEED, 10:35 AM 5/1/2003]

 

Ohh yeah, forget the chip and airfoil, they're 100% NOT WORTH THE $$.

 

Get a chip custom burned for your application....the generic ones don't do much... :cheers:

 

Just adding my $.02 worth. Everyone on the forum likes Hooker headers best. If you need emissions you will need to keep your air-pump, and get headers with the fittings for it. I have coated Hedmans that I bought before I got on the forum, and plug changes are from the bottom now, if thats a concern for you. I had to make a new brace for the AC, the dip stick, and find a spacer for the alternator brace. If you can get by with twin cats that would be best, if not, I used a single Random Tech in the stock location. I don't think our cars( I have an '86 ) have a frissbe, but I could be wrong on that. Good luck, and keep reading the forum. I'm sure you'll find plenty of good advice here.

:chevy

 

Best thing you can do for your motor and not get too expensive is exhaust work. I wouldnt have Hedman headers, cheap and poor quality, id only get some Hooker 2149s ceramic-coated. That alone should bring up about 10-15hp, with a whole new exhaust probably giving you 20-25hp.

Then you can do some 1.6rr, which could also give 10hp.

Other than that, just do the free mods. K&N filter/Open lid; TB bypass; remove the screens in the MAF (dont buy a high-flow); cut-back plugs; MSD wires and the AFPR will especially help with tuning.

I would not buy a custom chip until I was completely done with modifications for the future. Until then, a lower temp thermostat (160 or 180) and a fan switch will let your engine stay cool enough to make its best power.

I urge you to look at 65Z01s site for more directions, he'll see this one soon.

Anything further will be porting of the plenum/runners/base which you can do yourself and could free up 15-20hp.

More power than this can get you will require a bigger budget, but if you want to think about that, look at the Superram and accel 219 cam at lingenfelter.com.


[Modified by vader86, 2:08 PM 5/1/2003]

 

You are on the right track with exhaust mods. In addition a good cat-back, do a hi-flow cat (like Catco or Random Tech.) and either LT headers or cat-less mandrel bent front Y.

After the K&N filter with cut lid, install a 160deg stat and aux fan switch. Cleaning the debris from between radiator & A/C condenser would help improve cooling too. Porting the plenum & upper runners and gutting the MAF will add a little boost and prepare the way for air flow increases with future mods. The TB coolant bypass is nearly free and reduces intake temps for a little gain.

By then an AFPR will allow you to add more fuel at WOT to balance out the improved air flow for optimum mods effect.

You could install cut-back AC Delco spark plugs (see my site) for a nice "free" power gain.

An underdrive crank pulley (with overdrive alt pulley) will help too.

 

I did all of the above that Raistlin mentioned but I didnt have any cats and used muffler eliminator tips. I also had the accel base intake. I 'only' put down 250 rwhp and 'only' 350 rwtrq but my trap speeds in the 1/4 were equal to stock LT1s or better in some cases. My 90 put down 216 rwhp stock BTW and ran 13.5s at 105 - 106 mph after mods.

 

I'm tired right now, so I didn't read all of the replies. If I'm just spouting the same stuff everyone else did then ignore me. :)

The 1st thing you have to ask yourself is what do you want out of your car as a result in the end? Is the $1500 now all you want to ever spend on performance modifications or is this just going to be round #1?

Once you've decided that you can make more logical decisions as to where you want to go. :)