no headers, true duals?

[Vettefan87]

Depending where you go, you would have to modify those duals once you get headers. They will be made to attach to your stock manifold. I didn't really plan on getting headers so I just went ahead and put the duals on. However I am going to in the future have a complete system put on with headers, and duals straight back.

The only problem with doing it that way is that the car can only be used only for "off road use" if you hook it up with at least the main cat it will pass emissions.

 

[redc4corvette]

Your right the L98 kills the Lt1 to the 60' mark but after that its heads up until the last 20 yards, then the Lt1 comes on but the time slip shows .30 diff in the 1/4 .
But the L98 does have 3.33 D44, trans go kit 3000 stall and the Lt1 has D36 3.07,4L60Eand a smother ride.
The 86 is more fun from light to light.
I love the way the front end comes up in the air.
But on my exaust I cheated on the L98 I had a spare Lt1 mufflers and pipes and with the headers they fit and the diff is more than seat of the pants.
I just run cut outs on the Lt1.
Lt1 pipes are cheap and you can find them everywear.I would guess anyone could pick them up for free or just a few bucks.
Something to think about.

 

[vetteboy86]

So you put LT-1 headers on the L98?. Other then that the combo bolted right up huh. I am not too familiar with the LT-1 exhaust, how many cats are there, and what is the pipe diameter?

Craig

 

[WhalePirot]

If you order the headers you can get a front Y pipe that will plug into your main cat, and then you can use your stock rear Y pipe, back out to mufflers or eliminators. I am not sure why you would get duals, and then headers??

Me neither. I suggest listening to this.

Also, there is a difference in pipe size between header and exhaust pipes. They serve different functions, while both move the waste gasses rearward.

Equal length headers scavenge gasses from the combustion chamber, optimally at a certain RPM. Such requires velocity, which is decreased with too-large tubes. There are limited choices on the market anyway for our cars, but staying with a with a source that quietly posts successes, rather than shopping for huge tube headers will pay off.

On the other hand, the downstream tubes move the collected gasses and (obviously) must be larger. The table I found and referred to, had larger tubes for larger displacement engines :duh . A larger air pump, as our engines have been called, needs a larger pipe to move the air, or must work harder (restrictions) to move it (Boyle's Law http://www.grc.nasa.gov/WWW/K-12/airplane/eqstat.html ). Without benefit of the equations and data which is available to the LT-1 and L-98 designers of these pipes, we are restricted (actually, freed from the design of) to what is available in the market.

Just understand that larger is not always better.

I recommend choosing good headers that connect to your car's existing exhaust. BTW, as I have previously stated, I felt NO performance difference between having a decent CAT or a test pipe, on my somewhat modified stock engine. Therefore, I see no reason to run without the CAT(s).

I have no doubt that headers alone, versus 'duals' alone, will result in many more smiles for you.

 

[redc4corvette]

The Lt1 exaust you just cut out the resanator and install an X pipe, cut off
the forward flange and weld it to your headers or header flange.Lt1 pipes are just 3" pipes.
The L98 has 3 cats I dumped those.
Cheaper than the L98 exaust and then installing headers.

 

[fast.asleep]

I recommend choosing good headers that connect to your car's existing exhaust.

I'm confused, everything you stated before made sense but are you now saying adding headers to the stock L98 exhaust is a better choice than headers and dual exhaust?

If I remove the headers from the equation it seems your saying the stock L98 exhaust is preferable to dual exhaust?

 

[vetteboy86]

Sure does get rid of the headache when you take it to a shop for anything serious. I think that with the pre cats gone, and one free flow cat the L98 exhaust system is sufficient. However you can't beet the price for 2.5" diameter pipes all the way back. I think I payed 300 for mine, opposed to a set of TIPS headers for 750.:ugh

 

[fast.asleep]

I think that with the pre cats gone, and one free flow cat the L98 exhaust system is sufficient.

depends on your definition of sufficient.

 

[87blackroxi]

most bang for the buck

Trying to get the best performance for the money I have now. yes it seems kind of backwards putting the true duals and removing the cats, then later putting on the headers. but the almighty dollar prevails. From what i've asked around, the stock exhaust and cats on the L98 are one of the most restrictive there are. So it's a start on getting a better breathing beast. next month come the headers.

 

[fast.asleep]

Trying to get the best performance for the money I have now. yes it seems kind of backwards putting the true duals and removing the cats, then later putting on the headers. but the almighty dollar prevails. From what i've asked around, the stock exhaust and cats on the L98 are one of the most restrictive there are. So it's a start on getting a better breathing beast. next month come the headers.

I would do the same thing in your situation. Be prepared for your fuel mileage to go to hell for the first little while

 

[87blackroxi]

So I hear the gas mileage sucks pretty bad. Any idea if this pans out after time or only when the headers are added?

 

[vetteboy86]

I still get 25mpg on the road. In the city I am getting 15-16 mpg. As a matter of fact the vette gets the best gas mileage of the vehicles I own. So I would say no to getting poor fuel economy.

 

[G Winter]

I would do the same thing in your situation. Be prepared for your fuel mileage to go to hell for the first little while

Refering to the lead foot sydrome ?

 

[fast.asleep]

Refering to the lead foot sydrome ?

Yup

If your driving style doesn't change than my guess would be an increase in fuel economy. I've never been able to test that theory. I'd bet that after you hear and drive your car you you wont be able to either.

My mileage dropped into the single digits for a couple of weeks. (but boy was it fun!)

 

[WhalePirot]

I'm confused, everything you stated before made sense but are you now saying adding headers to the stock L98 exhaust is a better choice than headers and dual exhaust?

If I remove the headers from the equation it seems your saying the stock L98 exhaust is preferable to dual exhaust?

Sorry, no. I would install ceramic-coated headers first and add an improved CAT-back when you can. While 'duals' will probably flow a bit better behind headers than the stock system, I am not certain they will be any better than a new CAT-back and they violate Federal EPA laws. That, however, is totally for you to decide.

 

[fast.asleep]

Sorry, no. I would install ceramic-coated headers first and add an improved CAT-back when you can. While 'duals' will probably flow a bit better behind headers than the stock system,

the world makes sense again.

I am not certain they will be any better than a new CAT-back and they violate Federal EPA laws

I'm not either, that would be an interesting test. "Off Road vs Cat Back" If I find one I'll post the link.

 

[87blackroxi]

I'm not too worried about emmissions and epa. In florida we have no emmisions and you would be amazed at some of the crap on the road down here. I have seen cars that have plywood for hoods. some cars have no mufflers at all just the stock manifold and a 3 foot pipe that drags on the ground. It's a pretty lenient state.