Okay, afew years ago I had a free flowing exhaust made for my '83 Crossfire. 2.25" ---> 3" y-pipe, going into a high flow 3" cat, ---> 3" pipe into 2.5" tailpipes.

Anyway, I kept the stock, restrictive, LU5/LG4 exhaust manifolds on. Just wondering how big of a bottle neck they are now. I'm not interested in headers, but I do have a set of L69 HO manifolds. Any thoughts on whether it's worth my time to install the HO manifolds on my CFI? Will that extra 1/4 inch diameter give me much in the seat of my pants?

 

I swapped a full L69 exhaust (manifolds, Y-pipe, and intermediate pipe) to my LG4, but this was along with other modifications, so I can't provide a seat-of-the-pants opinion. The following link includes info on manifold size, and also a side-by-side pic of the LG4 and L69 Y-pipe. BTW, the L69 intermediate pipe was larger than the after market version I'd purchased for the LG4.

https://www.thirdgen.org/forums/exha...-question.html

BTW, note that the 2 1/4 aren't really 2 1/4:

https://www.thirdgen.org/forums/exha...manifolds.html

JamesC

 

Thanks James. I guess the other question which only I can answer is, if it's worth the 300 bucks in labor.....

 

Will the 2 1/4 manifolds and 3" y pipes work well on an LG4 with the stock heads?

 

Worked well on mine. Essentially you're swapping L69 equipment to an LG4.

JamesC

 

I suppose finding H.O. manifolds would be difficult to find. I would prefer them over headers.

 

I got mine on ebay. The seller had them for a "buy it now" of something silly, like $350 one week. When no one bought, they were relisted with no reserve the following week. I got them for $10. Shipping was $38 though.

I think I'll try to get them on by the end of the week and report back. I have to say that I expected more from my expensive, custom bent, free flow exhaust. Maybe the stock 2" exhaust manifolds are what's holding it back. We'll see.

 

I would like a pair for that price. So total cost including shipping was 48.00?

 

Yup.

 

good

 

This seemed like as good a place to post this as any of the other threads. This is what the factory L69 pipe looks like when you sawzall it. About 2.125" I.D. I have a set of 14071200 lh and 1407xxxx rh I'll sell for $25 + shipping. no air tubes, includes EFE that needs to have butterfly tacked to shaft (seems to hold vacuum).

 

Okay, got them on. I haven't driven it very much yet, but two observations:

1) When you get past 2500-3000 RPM you can really feel it pulling harder. It also seems to require a lighter throttle to maintain speed while cruising.

2) It sounds different. With the LU5/LG4 manifolds and the aforementioned exhaust, it had a sort of flatulent sound to it. Like small pipes dumping into larger pipes, which in fact was the case. It has a more pleasant burble to it now.

Two more items. The stovepipe on the driver's side was eliminated, and the butterfly valve on the passenger side was eliminated with a new pipe fabbed to take it's place. It really feels like I need to upgrade to 3.42 gears now.

 

Here's a picture of the "top of the line" L98 with dual converter setup.



Looking at it out of the car, it seems way more low performance than it would in the car. (Not my pics, I have the L98 manifolds with single cat, which is even less performance)



Cleaning up the stock manifolds.

Of course, like many, I want the Dyno Don headers.



I can't comment on the LG4 manifolds. Don't have any experience with them.

 

The N10 dual cat exhaust is what I really wanted. Mostly because of the way it sounds and how all the resonance and vibrations have been engineered out. Something that you can't say about some aftermarket setups.

After looking for a while, I of course found one locally one week after I had my shop custom bend a system from the manifolds back.