Getting the car on the road

[tweiss3]

I think part of my heat issue is the cats are 20 years old, and are starting their decline to fail. I want to pull the cat after echeck and put in a resonated race pipe from corksport. Also, both my mufflers are rotted out from age, so they need replaced. For the same money, i can get the single cat back from corksport and get some flow, so that's the plan. Plus then she will shoot flames naturally.

[NoDOHC]

You should read the exhaust threads, Corksport is LOUD. If you are Ok with that, then go for it. Racing Beat is about the only option for a reasonably quiet exhaust. You can sometimes find a Racing beat system used for a reasonable price.

[tweiss3]

alright after i read a few threads i guess i have a few options. Racing beat is expensive though, kinda out of my budget.

Mid pipe/cat/presilencer/resonator:
Magnaflow cat (will melt in the long run)
Corksport racepipe with resonator ($100)
Racingbeat presilencer ($235)

Catback/fix rusted out exhaust:
Corksport single ($370)
Racing beat dual ($635)
Bosal stock replacement pipes ($170) with magnaflow muffler (not sure which ones to go with)

Are these all my choices? I need to replace whats there asap cause its rotted at the mufflers and its starting to get chilly.
I would like a single cause it would drop weight, but i dont want super loud. I also cant afford to drop too much dime on an exhaust, or i would go racingbeat instantly with their header and all

[Pete_89T2]

The Borla dual catback system is another good choice, I've had one on my '7 since 2001 and it still looks & performs like it was brand new. The Borla is all SS construction (as in everything, not just the mufflers), and very similar in design to the Racing Beat dual catback. Sounds a lot like the RB system too - it's a little louder than the RB at idle & WOT, but it's a mellow deep tone. Long road trips won't torture you. Cost back then was in the $400~475 range.

[NoDOHC]

I have never heard a Borla in person, but I have heard good things about them.

I ran gutted stock cats, Stock Y pipe and Dynaflow straight-through mufflers with my stock ported 6-port with no problems with sound. Updating to Racing Beat headers and a straight pipe did not make the sound level intolerable on the 6-port (exhaust port diffusers).

Then I went 4-port (no diffusers)... WOW! I couldn't drive the car. After one test drive, I left it in the driveway until I found another exhaust solution. The Racing Beat presilencer made the car tame while cruising, but it still sings pretty loud when under WOT.

The best exhaust repair idea I had was buying a used Racing Beat exhaust (Complete from manifold) for $350.00. No more issues with sound (although this was on my '91 which was quieter with no exhaust after the manifold than the 4-port was with a full exhaust system minus the presilencer).

Basically, if you don't have access to a welder, Corksport may be Ok because you have diffusers in your exhaust ports. Otherwise, you could try finding some decent Piston engine mufflers and welding them to your factory Y pipe.

My thought with buying racing beat is this: If I will be spending money on something else and saving to buy the RacingBeat exhaust, I should just wait until I can afford the racing beat exhaust.

Watch Craigslist and eBay, sometimes you get a deal.

[tweiss3]

An update. New Magnaflow cat and corksport 2.5" catback installed. Passed emissions this time. Its not too loud, manageable for me. Is better than the rusted out mufflers were, and feels much better up top. Also, i switched to premixing, half to one, with the stock OMP in place just for good measure.

[NoDOHC]

Awesome! Congrats on passing emissions. I am glad that the cat fixed it.

I should say that the last time I failed emissions, I gave up on the stock ECU and went aftermarket. I found a broken vacuum line as I was removing the rats nest. I realize that is why it failed, but I put the Haltech in anyway.

The funniest part is that they did away with emissions for vehicles older than a '96 right after I had the Haltech tuned.

I still have absolutely no intent to go back. If you read my sig, you will see why.

[JustJeff]

Just thought I'd toss out a hello tweiss...I spent many years in NE Ohio...got my degree from Kent State. How's things going in the town that has more cloudy days than any other area of the US?

[tweiss3]

Lol, kent read, kent write, kent state (im an akron grad). Everything is survivable here i suppose, economy sucks though. Where did you move to and why.

Also, is it normal to be getting about 15-16 mpg mixed driving with my only mods being the exhaust and a cone filter?

Also, i want to replace the gear oil with schaeffers in both the diff. And the trans. Anything special i need to know? Any old gl4 should do, right? I have the stock open diff.

One last thing, any way to easily calibrate the spedo? Mine is saying i am going 5 mph faster than i am actually am going.

[JustJeff]

^I originally went to Akron but didn't like it. I lived in Akron but drove to Kent for classes. I left NE Ohio in 2001, right as LTV was going under and U of A was getting it's renovations.

I'm in Southern Indiana now and the economy here is pretty bad also. Whirlpool just closed up shop and moved to Mexico so things are pretty depressed here. I'm thinking of moving again....

[NoDOHC]

Originally Posted by tweiss

Also, is it normal to be getting about 15-16 mpg mixed driving with my only mods being the exhaust and a cone filter?

Also, i want to replace the gear oil with schaeffers in both the diff. And the trans. Anything special i need to know? Any old gl4 should do, right? I have the stock open diff.

One last thing, any way to easily calibrate the spedo? Mine is saying i am going 5 mph faster than i am actually am going.

15-16 is normal if you rev past 3,800 rpm frequently and do a lot of city driving.

If you want to help your fuel economy:

Don't rev past 3800 rpm (stock ECU runs terribly rich past 3,800 as it kicks in the secondaries - which it doesn't even need, I made 155 WHp on a single set of 460cc/min injectors).

Don't move the throttle any more than you have to.

Don't lug the engine too much (below 1,500 rpm stock ECU gets very rich again).

If you are willing to make modification, start with 10 degrees + on the ignition. this will get you 5-7 mpg.

Removing PS gets 1-2 mpg

Aero mirrors and spoiler get 1 mpg on highway

Eliminating catalytic converter picks up about 2 mpg

I got 30.7 mpg out of one tank on a hot day driving 75 mph on flat ground without any stopping. This was my personal record with the stock ECU. I typically saw 25 mpg city and 27 mpg highway.

With a 6-port and a Haltech E6X I never got below 30 mpg, even when I flogged the car around town. My record full tank fill was 38.5 mpg.

Short story, the factory ECU DRINKS gas.

My stock ECU '91 Auto trans gets 22 ish around town and 25-28 highway. (With ignition timing pegged at maximum advance). It still has the AC and Power steering. It also has the aero package.

I drive it like a grandpa (it is so gutless there is no point in flogging it).

If your odometer is correct, any attempt to correct the speedo will make it inaccurate.

The simplest way to recalibrate the speedo is to put the correct size tire on the car. The S5 speedos are much less trouble than the S4 speedos (which all read higher than you are actually going). If the tires are currently 205 60 R15s, than you may need to use a larger tire to make the speedo accurate.

It is possible that you can buy a speedometer drive gearset at a .90 ratio, but I don't know of a source for them.

You could also replace the final drive with a 3.90 or replace the instrument cluster.

With the stock ECU, I ran two sizes too small (225 40 R16) to get a little launch out of the gutless 6-port.