Caveboy

99 C5 exhaust manifold and C6 Z06 Exhaust manifold! Are there any differences and do i gain any horsepower and how much by going to the C6 Z06 with the mid-pipe

Caveboy

bikeriderga

They are not the same. All >2001 exhaust manifolds are the same.

You may gain a little power with the swap, but no seat in the pants feel. Better going with headers or LS7 exhaust manifolds.

RedZMonte

LS6 manifolds are different (TRI-Y Design)... Verry little to no gains.. LT Headers or LS7/LS9 manifolds will make a gain. I have LS7/9 Manifolds on mine with tune ~25-30WHP. LS7 does not have AIR injection so you have to add/modify the manifolds to work with the AIR system or remove it and tune it out. (I added to mine as you can see in the bottom pic... Swapping for LS1 to LS6 or LS7 will require a different Hpipe (to match manifolds) or modifying stock to mate up. Here is my install/dyno stuff on LS7/9 Manifolds: https://www.corvetteforum.com/forums...7-exhaust.html

'99 LS1 manifolds:


LS6 manifolds:


LS7 Manifolds:

Blue Thunder

I just put headers on my 2004....BIGGGGG difference in the Seat-of-the-pants-ometer.

Vetteman Jack

Go with some good LT headers. You'll see much better HP and torque gains from them.

john8642

Long tube headers are not an option if you live in California or other smog check states if you want to stay legal.

Caveboy

Any tips and tricks on installing the LS7 exhaust manifords

Patches

From a post above:
https://www.corvetteforum.com/forums...7-exhaust.html

Matt's install that helped me do mine :
https://www.corvetteforum.com/forums...sion-pics.html

My installation:
https://www.corvetteforum.com/forums...t-in-a-c5.html

joe's98

I just put Z06 manifolds and Mid pipe on my '98. My car came without cats and I wanted them back on. I bought the complete exhaust off a 2002 for $200 that had low miles on it. Little bit of a PITA to do. Took about 5 hours at a friends shop. We cut the mid put and put on a Corsa x pipe and mufflers too. No difference in performance, new diff is next. 2.73 is great for mileage, but not for performance!

Caveboy

Any good installers in Bay Area,CA? for the exhaust manifolds?

Patches

Ask this question in the NorCal section and I'm sure you'll get several suggestions.

spdrcr

Well, technically in CA the LS7 manifolds aren't legal on a C5 either so ......

john8642

Since the LS7 manifolds are an OEM part, they look stock. I doubt many inspectors would know the difference unless they owned a C5. Also, several people on the forum have passed the inspection without having to find a dishonest smog station.

Caveboy

Looking for somebody to install them in the Bay Area!

spdrcr

I guess a lot of that depends on how educated the smog inspector is and how the modification to add the AIR injection fittings look.

It is certainly one of the least obvious non-smog-legal upgrades and if the rest of the car is stock-appearing the inspector probably won't look too closely.

Regardless, there is still risk that the car could fail CA's visual inspection and a cost would be incurred to return the vehicle to a true smog legal configuration.

spdrcr

Start calling around. When you are talking about modifications that impact CA smog equipment not a lot of shops are going to want their name associated with that on a public internet forum. Technically this is still not a legal modification in CA.

RedZMonte

Alot of Cali guys run LS7/9 manifolds. the cats have OEM part numbers and the C5's are past the OEM Cat warranty one guy added dummy AIR injection bungs to his that kept the stock AIR injection look but was tuned out in the ca, just for visual inspection to be sneakey.

Here is "MADMATT's" install that i based my install off of. I did a couple things different, such as bent the AC line out of the way rather then grinding on down the flanges, My 04 dip stick worked in oem location so modifications there... I had no problem keeping the studs on the outlet flange rather then bolts (bolt together with both pieces lose between the motor and the frame before mounting the manifold to the engine) I also pluged the rear O2 ports and added them to the C6 3" Hpipe in stock C5 location and cut the stock Hpipe and mated it just before the rear Hpipe hanger so it bolts up like factory.

S

Crosis

Its actually easy to vote out politicians who support that BS law and vote in politicians who support performance cars.

john8642

As I said in another thread, I'll gladly put up with the hassle of smog regulations in exchange for the improvement in Los Angeles air quality from the '70s. I remember the days when outdoor PE was canceled because of smog alerts. It IS possible to have performance cars and regulation. As far as voting out politicians that support smog control, it's not going to happen. The country, and especially California, are moving in the opposite direction, which is why we will have 50mpg cars in the not too distant future.