mileage hit with ported heads? need advice
02-27-2007, 09:17 PM
#1
Burning Brakes
Thread Starter
mileage hit with ported heads? need advice
Just bought John Williams nassau blue '98 M6 Vette and I'm loving it so far! Just took a road trip with it to take care of some stuff in NC with my daughter and so far everything is peachy. And yes she gave me the giggle of approval... Naturally being me I want to fix every little thing with the car, most of which is small stuff. However, since I have a cam and exhaust only LS1 and I gotta pull the engine to do probably a pilot bearing (moans on release in 1st from a stop) and lifters (stock on an XE 226/230, they tick loud when hot), I was considering some ported heads.
I would love to put on some ported heads but I'm getting close to 550mi/tank on the interstate and dont want to take a hit considering this is going to be my main source of transportation. I was considering biting the bullet and splurging for the L92 heads and L76 intake since that would cover pretty much everything I want, but then I would need a different block and I have a 320mi. '98 LS1 in the garage. So unless I find an aluminum large bore block on the cheap (
) that might not happen since then I'd go for more cubes 
I have 4 or 5 months until I have to worry about it while I save my money since next week I go back to the sandbox.
So has anybody noticed a mileage drop on their LS1 car after replacing their heads?
Yes I will take the car in to get dynotuned again after the heads install. If I dont go for more cubes I will use the cam thats in there now.
I would love to put on some ported heads but I'm getting close to 550mi/tank on the interstate and dont want to take a hit considering this is going to be my main source of transportation. I was considering biting the bullet and splurging for the L92 heads and L76 intake since that would cover pretty much everything I want, but then I would need a different block and I have a 320mi. '98 LS1 in the garage. So unless I find an aluminum large bore block on the cheap (
) that might not happen since then I'd go for more cubes I have 4 or 5 months until I have to worry about it while I save my money since next week I go back to the sandbox.So has anybody noticed a mileage drop on their LS1 car after replacing their heads?
Yes I will take the car in to get dynotuned again after the heads install. If I dont go for more cubes I will use the cam thats in there now.
02-28-2007, 02:59 PM
#3
Pro
Member Since: Jan 2005
Location: Fayetteville NC
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The only difference being you'll probably be driving it a little harder do to the increase in fun factor.
02-28-2007, 03:53 PM
#4
Team Owner
Member Since: Sep 2003
Location: Raleigh / Rolesville NC
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But over all highway cruzing if you dont change your right foot habbits, very little difference.
Last edited by AU N EGL; 02-28-2007 at 04:20 PM.
02-28-2007, 03:53 PM
#5
Melting Slicks
i lost 7 mpg after FI, bigger cam, but my main problem i think was 60lbs injectors. (this is with cruise control set at 75mph run in 6th speed, getting 23-25mpg) was 31-33mpg before upgrades.
Last edited by tramminc; 02-28-2007 at 03:56 PM.
