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- - Stage 1 L36 engine kit on ZZP (https://www.gmforum.com/performance-brainstorming-tuning-96/stage-1-l36-engine-kit-zzp-193226/)

I only really know of one or two Bonnies that would benefit from this exhaust. One is a defunct Turbo'd car, who's owner doesn't post anymore. The other is Dr. Jay.....

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I only really know of one or two Bonnies that would benefit from this exhaust. One is a defunct Turbo'd car, who's owner doesn't post anymore. The other is Dr. Jay.....

And Scott Cooks 2000 SSEi that runs mid 11's, but thats about it.

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Originally Posted by dbtk2

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If you go for this kit then there are some things you should know:

1. The water pump pulley won't work on the series 2 engines because of the engine cross member. ZZP does offer up a light weight pully that may help.

2. The exhast should be at least 2.5. Most cars we have run 2.4, or two and a quarter.

3. Cold air intake is a must to get this done.

4. Yes you can do this in an evening with the right tools on hand.

I am going to have to agree with everything that was said in the quoted post except for #2. All of that stuff other than 2 is definately true. The stock exhaust should be plenty large enough. The Borla exhaust we have on the GTP is 2.25". I used to think it was 2.5", but then I did some research and found out that it is actually 2.25". And as you can probably tell, the 2.25" exhaust is flowing well enough for that car, and seeing that the L36 is N/A, has the same amount of cylinders and they are the same size, and is not making even close to that much power, I don't see any reason why it would need a larger exhaust...maybe I am just stupid, but that is my opinion on that.

The reason I say what I say in #2 is because I just opened up the ehaust on my 3.8ltr. SE and it's made a BIG DIFFERENCE in how the car runs. Haven't take the car to the quarter mile track but in the eigth mile track I'm getting times that have droped from 10.1 or.2 to 9.8 with a best of 9.7 ...... and this after I've gained 20 lbs.
To make sire we're talking the same size.:

2.4 = 2.25 (two n a quarter)

2.5= 2.50 (two n a half)
:wink:

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I know I have heard of people getting gains by opening up their exhaust, and I believe you probably did. It all depends on the flow characteristics, not size. Putting the Borla exhaust on the GTP made a noticable difference in performance over the stock exhaust of the same size because the Borla exhaust had less sharp bends. But, it isn't the size of the exhaust on the car, it is the flow. So if you replaced the stock 2.25" exhaust on a Bonneville with a custom 2.25" exhaust you could gain or lose horsepower just by how you bend the pipe. I am not saying you can't gain power over the stock exhaust, just that you don't need bigger piping, and that it doesn't make much difference (even if you do feel it) unless you are Forced Induction or a re making serious N/A power.

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To make sire we're talking the same size.:

2.4 = 2.25 (two n a quarter)

2.5= 2.50 (two n a half)

Yup, I am talking 2 and 1 quater inches.

After looking at the exhaust under my Bonnie as compaired to the GP. I did notic that the Bonnies tend to have more bend in them. If we are talking a straight pipe as compaired to one with many bends then I do think what you say is possible. ...... But I think now that I'll try to go with a bigger pipe that is also straighter,(custom). Becaquse I do plan on making gobs of power with the bonnies L36. As you say about power; with the time I'm putting down in the 1/8th; it is very possible that my GP will run the quarter in under 15 secounds now. If I am wrong then I'll let you know.