Daggle Bentwood

Has anyone had headers and x-pipe installed (with and without a tune)on a '09 ZR1?

1 BAD ZR1

Putting headers on your ZR1 without a tune will decrease your power. The extra flow you gain by adding the headers will decrease your boost pressure. You will need to put a smaller pulley on to compensate for the loss of psi.

Daggle Bentwood

What make of header did you install?

1 BAD ZR1

I have Kook's headers, high flow cats and crossover pipe.
A friend of mine has American Racing Headers on his ZR1

Daggle Bentwood

Did you replace the pulley or tune?

Richie18

Well then which one is it? A tune or a smaller pulley?

From what i've heard the headers will decrease the boost pressure but in the end gain hp. To really take advantage of the extra flow, yes a tune and smaller pulley would be great.

Here is what i've seen

A.R. Headers Pics And Dyno Results!!!

DoctorV8

Incorrect.

Please don't confuse decreased boost with decreased power. If exhaust scavenging improves (as it does with headers) boost will decrease, but since you have actually improved the engines volumetric efficiency, power will increase. A proper tune is necessary, of course.

By your logic, I could install a 1.5" catback on a supercharged car and double the boost it makes at the manifold. Will that double my horsepower?

1 BAD ZR1

Both.

Next is a cam, head work, heat exchanger/intercooler work and maybe methanol if I can't control the heat soak problem.

1 BAD ZR1

My buddy put just headers on his ZR1 and then dynoed it. It had zero gains in HP.

1 BAD ZR1

Whatever, you don't have any room to talk. I own one of these cars and so do two other friends of mine. We have experimented with all of them and I/we know what happens when certain items are added to this car. Experience with this paticular vehicle overrides your comments.

GForceSS

No doubt you guys experimented, and while I cannot say anything about your results, I can say I’ve never seen a SC car act like that. They usually drop in boost and in worst case scenarios only pick up a few HP until the boost is move back up; usually making far greater gains than boost alone.

Jorday

Those with headers, did you run the x pipe with high flow cats or the off road x pipe? I keep flip flopping on what I want....

DDSLT5

LOL - very nice.

Actually - forced induction doesn't change depending on the car, and it is not necessary to own a ZR1 to understand the concepts involved - it is all the same. The Doctor's comments are not only valid, but 100% correct. Headers will definitely make more power with a tune, and that power will come at a lower boost level. If you drop a pulley size, and return to the previous boost level, then you'll make even more power at the same boost level as pre-header. Of course, the tune must always be adjusted accordingly.

DoctorV8

Congrats dude....you and your two friends own ZR1's....the baddest Vette ever, and apparently the only Vette ever that was immune to the laws of thermodynamics. Enjoy.

You do realize there are more variables at play here than just headers....while headers without a tune may not do much, I guarantee there is some power to be had there.

The REAL issue is that you are confusing less boost (after adding headers) with less power. Less boost is a function of decreased backpressure and therefore less restriction. BOOST and FLOW are two different metrics, and your understanding of this has NOTHING to do with ZR1 ownership.

DoctorV8

Interesting.....didn't you just say above that

So it didn't lose power, a testament to the flow of the stock manifolds. Again, too many variables...were the IAT's the same before and after? Was the car retuned after the header install? What were the AFR's?

red vette nut

okay I am not a tech guy at all, but I need some help in understanding correctly what this thread is discussing.
I have a 2009 ZR1.
The previous posts have different opinions on headers.
If you don't get any HP gains why would you put them on?
Would you have to change the pulley and thereby increase the boost to have any benefit?
Would additional heat soak cut down your power more with the pulley change?
In doing so can you still run on pump gas?

Thanks for any info you can give.

AR Headers

1BADZR1, We've never seen a power loss with headers on a supercharged GM, Ford or Chrysler product. Our testing HP gains with 2lbs. less boost. Your friends ride saw no gains though he lost boost. Anyway you look at it, it is a vast improvement. Replacing the lost boost I guarantee you will be worth a ton more power. BTW, Innovators West I'm told is working on a lower pulley/dampner that'll put that boost back in. You guys may want to look into it.

Nick

HamadoZr1

I have only one question for u, I have installed American racing headers without cats and with tuned, the question is? Why I feel the car throttled?
Should I change the cats or what I have to do?

I brake for nothing

Boost is an indicator of back pressure - a measure of restriction. Dropping "boost" from the header swap just means your engine is moving more air without the same restriction in place which is the whole point. This is increased efficiency. But you would need to tune the engine for this and as mentioned above you can pulley up the blower for even more air movement at the previous "boost" level.

Bendarwesh

running kook's with catless x-pipe before tune on dyno jet it showed 513rwhp after tune 566rwhp running on 98 octane