Believe it or not I still have the complete stock exhaust on my 86, and think I have an exhaust manifold leak. I'd like to replace the entire sytem, but I cant afford to right now. Am I better off getting headers or just a Front Y pipe w/no cats? How much power is there to gain with just headers on a complete stock exhaust system? I can't decide between just getting rid of the pre-cats, or throwing some headers on there. Headers = $! :crazy:

 

You should gain about 15hp from longtube headers.

 

15 hp only?
It's possible to install Long tubes + extra pipes to main cat on a Auto?
Hedman?, Hookers? ...
-Beppe-

 

You act like 15hp is nothing. What do you expect to get? With a full new exhaust, you could gain 20-25hp.

Then you have to move to the intake.

Of course, if youve already modded the intake fully, youll gain more than 15 from headers.

Id use Hooker, NEVER heddman.

 

That's actually more than I was expecting, consider the rest of the exhaust is stock. TPIS has also re-designed their headers to work with straight plugs, ... the price sucks, but the fit should be great.

 

Why? Just cuz Heddman's are uncoated? Same price for a set of coated hedmann's as it is for a set of hooker coated with egr stuff. I actually PLAN on gettin Heddman's, because with the 1 5/8 primaries, as opposed to 1 3/4 I may be able to get the torque up a bit higher (That's ALL I care about, because hp is a diretive of torque)

 

Yes I was thinking to a complete exh. system with a medium modded intake..
I know, 15Hp are a good increment....

 

I'm the original owner of my '86, and this is what I did before I purchased a set of TPiS Headers:

#1) Remove your stock Cat Converter, and hog out the inside for better exhaust flow. As you get into the job, you'll see all the packing you're eliminating. Use whatever tools you can get your hands on to do the job.

#2) Replace the stock Cat Converter.

#3) Purchase a set of performance mufflers. There are many from which to chose. I prefer Flow Master's, and I purchased mine from Summit, and paid $93.95 each back in 1993, and I'm still running them.

Summit still sells them, but they cost $105.95 each today. If you are interested...here are the part numbers:

FLO-425501-L (left side)
FLO-425501-R (right side)

You can call Summit at 1-800-230-3030 to place your order.

These mufflers have a deep throaty sound, and are built to perform.
Mine have been on my Vette since June of 1993 (checked my records).
Quality of this muffler is darn good, which 10 years of use, and at least 60K miles, I can prove.

I can tell you, when I completed steps 1 thru 3 above, and then started my engine...the sound alone was so much more impressive...and I do remember how much different the response felt when tapping the gas pedal.

The real test came when I got the Vette out on the open highway, and got into her a little bit.

I kept thinking to myself...I think I did free-up 25-30 Horsepower for just a couple of hundred bucks, and a bit of labor.

It was at this point that I decided my next purchase would be a set of headers.

I was not a Forum Member at this time (as a matter of fact, I don't believe the Corvette Forum even existed at this time...1994)...but I started doing my 'homework' on all the muffler information I could get my hands on.

I decided on TPiS, because a friend of mine added them to his '87, and I saw how easy they went on, not to mention the quality was so much better then the set he was removing...which I remember him saying, "they were only 3 years old."

I did order mine with the 'coating', but they are tarnishing to the point that I'm hoping to remove them at the end of next summer, and get them 'jet coated' again. I know I've got at least 50K miles on them.

I don't want you to think I'm trying to 'push' any of these products on you,...
rather I'm trying to present to you what worked for me on my '86 Vette.
I'm just trying to give you an option, on how to get some great performance value...for just a couple of hundred bucks. :yesnod:

Do some 'homework', and good luck with your decision. :cheers:

John

 

Heddman=low quality
And you can get the Hookers in either of those sizes.

 

:iagree:

 

Thanks for the advice John. I definitely plan to go that route, just in a little different order. :)

 

From personal experience I'll tell you that headers are one of those things that people get way too caught up on peak numbers with. I already had some mods when I did my headers (and mufflers and x-pipe). I picked up 23 hp. I picked up 44 hp when I had done the cam and such yet the headers were the better seat of the pants improvement.

The reason is that the cam gave me a mere 12 pounds of peak torque increase, the headers gave me 32! Since the HP peak is typically near the end of your rev range you rarely feel it that much. Meanwhile the torque peak is usually somewhere in the middle. Increasing that torque peak by that amount gives you a substantial difference in your mid RPM horsepower, not just all top end. So for where most of my driving takes place I noticed the headers more than the cam even though the cam actually gave me more peak horsepower, the headers gave me more under the curve.

I use Hooker 2151 headers and have been very happy with the results BTW.

Here are some dyno graphs to illustrate the point. Here is my stock graph, notice torque is perfectly flat, right around 300.



Now after the Hot Cam. Torque is a little higher but not really enough to feel, it's still perfectly flat, most all of the gain came from the upper revs. A nice gain with noticeable track time improvement.



Finally after the headers look at this graph. The mid range torque is up around 350, which takes mid RPM horsepower with it. This netted a solid 3 mph increase at the track and the best seat of the pants mod I've done yet.



Before the headers the car was fast. After the headers the car is fast and squirly because of the extra torque, which means more fun :cheers:

 

I would really recondisder that man. If you think you'll be giving up torque by going with 1 3/4's just look at my dyno graphs above. Not only do you still gain a LOT of low end you'll also see a healthy gain on the top end. There is no need to restrict yourself to pick up just a tiny bit more low end at the cost of a lot more on the upper end.

 

:iagree:

I didnt pick up staggering peak HP/TQ getting headers (about 10rwhp/10rwtq), but with the porting work on the plenum, I was able to flatten and extend the power band and pick up some much needed HP/TQ at the upper RPM range. I think I picked up around 20rwhp/20rwtq at 5k RPM after the headers and didnt lose any TQ at the low end.