Exhaust 2 to 1 ... MY CUTLASS IS BACK!

[Seshomaru7]

Hello, I am new here. I bought a '93 cutlass supreme convertible as my first car about a year ago. Last May, some lady in an SUV hit it head on at 40 while I was stopped in a turn lane. I was put at fault because that's how Floridian cops are, and the car was totaled. My Dad said the car wasn't worth fixing and instead, I got a '97 Chevrolet Cavalier RS. I missed my Cutlass. My Dad and I found someone to fix the car and he has been working on it for a while now. I am getting it back next Friday, so I need to start thinking about what I am going to do. I want to know what are the top mods I can do to increase HP, without necessarily taking a dive in gas mileage. Secondly, I would like to know the ins and outs of an idea I had. Taking both exhaust pipes, and putting them into one, then going straight out to the back muffler. Would this give it better sound? etc.

[19Cutlass94]

First, Top mod to be without decreaseing HP would be to go turbo. Youll still get good gas mileage with it.

 

Second, Both exhaust pipes as in the manifolds? Im kinda not understanding that one too much. You have the exhaust manifolds, the x-over, which convert into a downpipe and its single pipe on back...

 

What motor is in it?

[Seshomaru7]

I don't have the money for a turbo, so I was thinking of things like new exhaust, or intake. What is an underdrive pulley do?

 

I am talking about once the exhaust pipes come together, keep them as one pipe all the way back. I have the 3.4 DOHC, so the exhaust splits after the x over.

[19Cutlass94]

Intake wont do much unless its CAI. You can try some port and polish, you can have the heads milled down .009 ( which is what my friend did on his GP, RPE ) to give you more lift and duration.

[Seshomaru7]

What are the typical gains off all those things? and what exactly are those?

[19Cutlass94]

Honestly I dont know. Ive never seen a dyno sheet of a 3.4 DOHC with anything done to it. But the port and polish will help out, give you a couple more HP, the underdrive pulley will give you more power, and the heads, with everything you could be looking at maybe 20HP? I think thats a reasonable guess. and what exactly is what?

 

[Seshomaru7]

What is getting the heads milled down .009

[19Cutlass94]

Well you have the stock head as it sits. getting it milled down means you take ( in this case ) .009" off the bottom of the head. So basically your shaving the bottom of the heads. By taking this much material off, it allows the vlaves to lift higher and stay open longer.

[Seshomaru7]

I am thinking of some more basic ways to upgrade. I was looking into a turbo, but I am too poor for that. I am going into the Air Force soon also. What car do you have? What upgrades have you done?

[cutlsp]

the most restricive parts in the engine are the intake and the DOWN pipe.

[Seshomaru7]

the most restricive parts in the engine are the intake and the DOWN pipe.

I saw the intake for the W-body cars on eBay? Are those any good?

[19Cutlass94]

the most restricive parts in the engine are the intake and the DOWN pipe.

I saw the intake for the W-body cars on eBay? Are those any good?

 

Dont buy that stuff on ebay. Either make your own CAI, or keep it stock. with WAI, youll end up loosing power, which not what you want.

[Seshomaru7]

Do you know anyone on this site that would sell one? I am not very good at metal working!

[94CutlassSLCoupe]

Well you have the stock head as it sits. getting it milled down means you take ( in this case ) .009" off the bottom of the head. So basically your shaving the bottom of the heads. By taking this much material off, it allows the vlaves to lift higher and stay open longer.

 

actually, it will not affect the valve lift at all...all that milling the head will do is increase the compression ratio by decreasing the combustion chamber size and therefore also reducing the piston to valve clearance

[Seshomaru7]

Well you have the stock head as it sits. getting it milled down means you take ( in this case ) .009" off the bottom of the head. So basically your shaving the bottom of the heads. By taking this much material off, it allows the vlaves to lift higher and stay open longer.

 

actually, it will not affect the valve lift at all...all that milling the head will do is increase the compression ratio by decreasing the combustion chamber size and therefore also reducing the piston to valve clearance

Wait, wont shaving space off it actually increase the chamber size?

[19Cutlass94]

Well you have the stock head as it sits. getting it milled down means you take ( in this case ) .009" off the bottom of the head. So basically your shaving the bottom of the heads. By taking this much material off, it allows the vlaves to lift higher and stay open longer.

 

actually, it will not affect the valve lift at all...all that milling the head will do is increase the compression ratio by decreasing the combustion chamber size and therefore also reducing the piston to valve clearance

Wait, wont shaving space off it actually increase the chamber size?

 

No, it will decrease. Because when you shave material off the bottom of the heads, it brings the chamber, valves etc closer to the cylinder. Therefore decreasing the size. and like 94cutlassslcoupe said ( well actually kinda corrected me ) increase compression because that chamber is smaller.

[Seshomaru7]

Well you have the stock head as it sits. getting it milled down means you take ( in this case ) .009" off the bottom of the head. So basically your shaving the bottom of the heads. By taking this much material off, it allows the vlaves to lift higher and stay open longer.

 

actually, it will not affect the valve lift at all...all that milling the head will do is increase the compression ratio by decreasing the combustion chamber size and therefore also reducing the piston to valve clearance

Wait, wont shaving space off it actually increase the chamber size?

 

No, it will decrease. Because when you shave material off the bottom of the heads, it brings the chamber, valves etc closer to the cylinder. Therefore decreasing the size. and like 94cutlassslcoupe said ( well actually kinda corrected me ) increase compression because that chamber is smaller.

Oh, I get it now... Won't you need higher octane fuel then?

[19Cutlass94]

That depends on how much material you shave off the heads and how much you decrease that chamber by.

[Seshomaru7]

That depends on how much material you shave off the heads and how much you decrease that chamber by.

What's the cost to get that done?

[Euro]

as far as your exhaust goes, the only place where the piping splits is right after the rear tires correct? into a y-pipe and then out the back? i cant remember for certain, since i dont own a dual exhaust car lol

 

 

but i'd keep it duals, going single wont really increase performance or sound(actually single might make it quieter). The only thing going single exhaust will do for you is lose weight(like what 20 pounds at most?)

 

and as far as intake's go, i'd either do a true FWI, or just keep the stock airbox, gut it out a bit, and put in a K&N drop in. Then maybe polish your TB a litle

[SigEpCutlass]

T

the most restricive parts in the engine are the intake and the DOWN pipe.

I saw the intake for the W-body cars on eBay? Are those any good?

 

That stuff is garbage...make a custom FWI, and get a new cat back exhaust.

[Seshomaru7]

Does anyone around here make a custom intake for the 3.4 DOHC engine? What is the regular cost of a cat back system? How about a high flow cat?