I'm trying to figure out what type of setup I'll be going with this summer, more I read what options are available, more I get confused.

I already have a 2.25 inch cat back on the car that I would like to keep, since I don't want to spend to much $$. I figured I would go with some coated headers (TPIS or Hookers) with a 2.5 or 3 inch front Y pipe and a high flow cat.

Is this combo possible? will the high flow cat mate up with a 2.5 or 3 inch front Y pipe and a 2.25 inch rear Y pipe?

This is very confusing :confused:

Thanks!

 

Short answer: any of the Vette-specific headers and front Y-pipes will work with a high flow cat and your cat back.

Longer answer: for your motor, 1-3/4" headers are what you'll want, but I have heard of clearance problems on auto tranny cars. I can't remember if this is only the 4L60s or if it's on the 700R4 cars like yours as well. You'll want to check into that first. The other thing to keep in mind is that with that motor and long tubes (if they'll fit), your 2-1/4" cat back will become the new restriction in your exhaust system. If you decided to sell that and get either a 2-1/2" or 2-3/4" cat back, you'll be better off, but that's a decision you have to make based on your situation.

 

The TPIS coated headers into a 3" Y into a hi-flow cat should work quite well; you're looking at about $1k US.

 

Very possible. In fact, I have the same cat-back as you. I have the Hooker headers, and they fit fine. Its Hooker's 3 in. 16720 front y-pipe that can have a clearance problem. If your car is automatic, expect transmission pan clearance problems with this y-pipe. Then I have a random tech hi flow cat. The front is a 3 in. opening that matches and slides onto the 3in. front y-pipe and the rear mates with your Force II cat back via a two bolt flange. Just be sure that whichever front y-pipe you go with, that you will be able to attach it to the cat you end up choosing. In other words, do not buy a cat with a 3 in. opening for a front y-pipe that has a 2.5 in. opening. You do not really have to worry about the rear y-pipe since the end of it is enlarged to fit most cats despite it beeing only 2.25 in.

 

Cool!

I understand

Now, about that clearance issue? will I have clearance issues with the front Y pipe and the tranny oil pan cover if I go with a 2.5 inch front Y pipe? (I have an automatic tranny).

And were can I order hookers inside/outside coated headers from? do you guys have a web site I can order from? and were can I order the Random tech high flow cat?

keeping in mind I'm in Canada

Thanks guys!

 

HOK-2151-1 at Summitracing.com for the headers, around $550, although I think that there are those who would say that the Hooker coating is inferior and you should buy them uncoated and have them coated by another vendor. These are the ones without the AIR tubes and have no O2 bung. Don't know what your emmisions concerns are there.

 

[quote]

Now, about that clearance issue? will I have clearance issues with the front Y pipe and the tranny oil pan cover if I go with a 2.5 inch front Y pipe? (I have an automatic tranny).

[quote]

The clearance issue with Hooker's 16720 3in. front Y-pipe has nothing to do with it beein 3in. instead of 2.5in. There is plenty of room under there for a 3in. pipe. For THIS y-pipe, Hooker does not specify if it's for an auto or manual trans car. The flaw lies in how they shaped one of the bends that go arround the trans pan. I can tell you from reading other members post that only the auto trans guys had problems with it not clearing the pan on the passanger's side. I personally had this problem too. And even if you manage to barely make it fit, it will block some of the pan bolts, therefore you will need to remove it to change the trans pan gasket and filter in the future, and not seal properly at the header flange. I had to cut the corner section and reweld a new piece to make it clear properly. The 2.5in. or 3in. size does not create clearence problems. The fit is all in how correcly the pipe is bent by the specific manufacturer to what it needs to be under the car. That was just a heads up on Hooker's 16720 just so you know what to expect if that's the one you choose, since you have an Automatic.

I got my Random Technology high-flow cat from TPIS. The cost was around $220. A little expensive, but I needed one for emissions here in Cal. IF you do not have to deal with emissions inspections in Canada, you can just replace the space where your cat would be with an aditional lenght of exhaust pipe to fill in the gap, and save yourself the cost of a high-flow cat.


[Modified by 86PACER, 11:23 PM 1/20/2004]

 

Thanks for the explanation 86Pacer

I don't have to meat emissions in Canada, but I still want to keep the car smog legal in case I need to bring it into a garage to do some work on it and because I'm a bit worried about the environment. :rolleyes:

I will also get that Random tech high flowing cat from TPIS, and I think I'll get their coated headers with emission tubing. The 3 inch front Y pipe comes with the headers and I'll order the EGR tubing as well.

Is there also the same type of clearance issue with TPIS?
I'm guessing there is.

 

I also got my RT cat from TPIS as they had one of the best prices I could find.

The only issue I've read about with the TIPS FL headers concerns the fuel lines on the passenger side. I believe they simply need to be repositioned a little further up the frame before they bend down.

 

Man oh man, I always seem to have another question..

I've heard that the Knock sensor will sometimes read false knocks with LT headers.

If I understand correctly the knock sensor is attached to the stock header on the passenger side.
What is the best way to prevent this issue when installing LT headers.

Thank again!
:cheers:

 

The knock sensor is located on the block below the starter on the passanger's side.

 

Does any one know if headers cause false knock readings? and if so, what is the best way to stop or prevent them?

 

One of our members was having false knock problems after installing LT headers and just found that one of the header tubes was hitting the frame on the passenger side. I don't think you will have knock problems if they are properly installed.

You may however need a 3-wire heated O2 sensor, especially in a cold climate.

 

Thanks for the tip for the heated 02 sensor, I was planning on Installing one.

:thumbs: