Thread: We made a 3`Stainless straight ultra quiet exhaust and WOW, what a difference...

Originally Posted by Anthony Smith

It seems like you maybe over think things sometimes? Thousands of people have already been down the path your starting down, myself included which is why the same answers come up over and over. It is simply that the people that have been there and done it, seen it drove it and blew it up twice dont need to examine the theories behind it they just know what works and what doesnt. Also it has been proven time and time again that the factory catback has very little restriction and on a stock setup you would be lucky to gain anything from changing it.

I made a few changes at the same time. Hard to point out what did it but there was a very large gain, more than I expected. Anyhow we will never know exactly I'm not putting the stocker back on lol !

btw I have read almost every advice on this forum and others and the same answers always come out. I paid attention as it is a timesaver. Although I know a lot of forced induction, every platform has it's quirks.
But I do believe the advice is more appropriate towards daily driving vehicules running pump gas. This engine is obviously very prone to knock and therefore modding must be done carefully and that is the advice given here in general.

So, if you are putting another motor in the back will this be converted to AWD?

Originally Posted by txslow6

In for vids of the exhaust. So you will be doing a rear engine setup?

Yes !
I was looking at a 5.3 4t80E swap but thge summer is flying by and we have a lot of projects to do. This is just for my personal fun, not for business.
So another L67 will go in the back most likely. Easier to get wiring ECM and engine/trans as well.

The exhaust is amazing turned out very good. We do a lot of exhaust for snowmobiles and they require very quiet but very high flow.
These turbo sleds make 255HP on pump with 1 liter engine and 320HP on C16 maxed out (stock block stock turbo)
The challenge was to make a tough exhaust that can handle very high EGTs sustained and that was extremely quiet.
As well as being straight through for max performance.

Originally Posted by TheNoob23

So, if you are putting another motor in the back will this be converted to AWD?

Yes it will be then an AWD car. With the weight reduction I figure it will weigh around 4150lbs... but ultimately make 800-900HP total.
Should be a fun car. I will install the 18" E.T. street on all four to retain streetability.

What about suspension plans

Originally Posted by Fivefingerdeathpunch

12.2 is pretty dam lean if you ask me.

Agreed, I didn't touch the fuel maps yet. This is all stock ECU...
I just changed trans shift maps and rev limiter / torque management.

On race fuel it's fine but pump gas I will tune it for 11.0 to be safe.

Originally Posted by TheNoob23

What about suspension plans

My plan is to use the stock engine cradle or an aluminum cradle (worried about aluminum for 600whp) any info on aluminum cradle ability to handle gobs of torque would be very appreciated.
Front Coil overs in the back if I can for weight saving. Will need to adjust for extra weight and transfer.

Why would this thread be locked ?

Hey guys, here is a pic from the HPT log of the car from tonight's testing. This shows the Maf readings of 31 lbs per min.
As well as the boost level seen with the 3.8 pulley (Map KPA)

Originally Posted by slick2500

I also want to see a video of the exhaust.

I'll make one for you guys tomorrow !

Originally Posted by GTPpower

Looks like you are making some good power according to that scan. I would recommend that you richen it up a little when you drop pulley sizes though, even if you aren't seeing knock.

Stock exhaust manifolds will make more power than all the people one here that tell you, "you need headers for your stock pulley car, or it will blow up ohhhh emmmmm geeee."

We have a local guy running meth injection through the blower on a 3.2 pulley with 91 octane and no knock. He switched to E85 a month ago, and dropped to a 2.8 pulley. On stock manifolds. No knock.

I do have question for you. I'm also after a nice, quiet exhaust that flows well. Is it better to use two smaller resonators with a pipe in between like you did, or would one big resonator be better?

According the extensive exhaust testing we have done in other applications (turbo), the main factor is how long of a muffler total and size of the holes in the pipe and also packing style and density.

But for your questions it's simple one long resonator of the same style (same hole size and packing material and density) will be the same as two smaller resonators of the same lenght and pipe size.