No direct experience from me. Have you posted the question at LS1Tech? Hopefully someone there will respond.

 

I posted on Pro Touring but will look into LS1 Tech as well. Thanks!

 

It’s my understanding the stock tune is rich on purpose to avoid damage due to running lean. I’d get it tuned by a competent tuner.

Exhaust leaks prior to the O2 sensor will cause it to run rich. Some diagnostic scanners will let you log fuel trims which can be very useful.

I am not a fan of that cam. The 495 cam is much better.

Don

 

I like the 525s but they are not going to get the same mileage as a 430 or 480.

Did a swap for a friend 69 Camaro LS3/480 TKO 600 and 3.55 rear got 20-22 trip. Average overall most likely close to what you're getting depending on how much of the 4000 was freeway and how much was city and spirited driving.

IMHO your rear gear 3.23 and a T56 is not helping. If its a .63 6th nothing less than 3.73 and if .50 a 4.11 would be better

 

It's a T-56 Super Magnum so 6th is a .63. Are you saying the 3.23's are hurting the gas mileage or just not helping in general for overall experience?

 

Not the 525 that your asking about but I have a new 430HP and when I drove it to the Daytona Turkey Run I purposely attempted to see how much I could squeeze out of her and got 22mpg while there and putting my foot in it a lot I got 14mpg.

.

 

This seems consistent for what I've read and hear from folks with the other variants but those with the 525 seem to remain awfully mum about the mpg.

The past weekend at a Saturday morning parking lot get together a gentleman with a C3 Vette sporting the same 525/T-56 was claiming 31 mpg from Vegas to Tonopah (fairly flat drive) on the base tune but I can't say I believe them.

I'm getting around 9-10 in town with moderate driving and only 12 on the freeway.

 

530 hp from a low lift cam pretty much means poor efficiency imho….

Don

 

They use low lift and longer duration. Easier on the valvetrain. I liked mine. I really never thought about mileage. More about Smileage

 

Consider this a bump, but won't tire size also effect the milage?

 

One person on LS1Tech said he was getting 10 mpg with the ASA cam. Still hoping I can find some additional data points and possibly find someone who has experiencing with tuning and whether it's necessary or if I should leave it fat and happy.

The engine is rather obnoxious with fuel smell from the 10 deg overlap but I just didn't expect it to be so thirsty.

 

My 535 did not have the fuel smell. Might want to check O2 sensors and look for exhaust leaks. Exhaust leak will cause sensors to read lean and the ECU will dump fuel.

 

I have the LS3 525 with a TSP cam I use the holley terminator max as ECU T56 magnum and Currie 9” with 3.89 gears and I average around 20 MPG mix of city and highway but I also drive with a heavy foot. If I stay out of it I get closer to 26 mpg.

 

Exhaust leaks prior to the O2 sensor will cause it to run rich. Some diagnostic scanners will let you log fuel trims which can be very useful.

Hey everyone,

I'd like to know what mpg folks are pulling with the GM Connect and Cruise 525 (LS3 w/ ASA Cam).

I have around 4,000 miles on the block, T-56, 3.23 gears and I'm only averaging 9-13 mpg. Car has stock tune from GM controller.

I know the car runs rich with the overlap but I'm curious real world baselines for comparison. There are few threads on the internet with real numbers, but a couple do mention 10-12. This is a far cry from the 15-28 people report with a stock LS3 or other variants.
Speed Test
Appreciate any responses.

 

This is a fuel injected crate engine right? ASA has a lot of overlap as you know.

You might benefit from a tune. I run a 227/243 cam in my L99 (LS3 variant) in my 5th gen and we did a lot of tuning to it to get it right and I personally also played with the injector offsets because it was pretty smelly.

I will probably tune it again since it's been some years since I last messed with it.

Your 3.23 gears help with fuel economy, You are probably cruising at 2 grand or even less.

/co founder LS1Tech