L99 owners with slow cars going to dealers for fix.

[PQ]

Originally Posted by uke

Very possible. If the engine is working harder to spin the wheels, which is what the dyno records, then it may be losing power that way.

What actual amount is lost is hard to say (I have no concrete insight on that issue). Although I doubt that bigger wheels alone are enough to make a car that "should" dyno at about 340 have 35hp less.

I'm not that knoweledgeable about Camaro options. Are the wheels you have a factory appearance option, or are they aftermarket on your own? 21" is a pretty big wheel regardless.

I think the easiest practical steps you can take to pinpoint the issue are:

- if you still have them, put your stock wheels back on and see if there is a difference

- find someone local with a tuner that can scan your car while driving (if all else fails, go to ls1tech.com and check the regional sections), then you can tell for sure if KR is holding you back.

If it's not the wheels or KR, next culprit would be either over-aggressive torque management in the auto trannys or the DOD doing funky things, although I'd assume that this issue would be more common if either of the above were the case. I do know that tuners of previous gen DOD engines just turned theirs off to never deactivate (I'm talking the recent Impala SS's, other LS4 models, etc)

So safe to say that my 21" wheels as opposed to the stock 20"ers shouldn't be the difference of 1.5 secs to 60?

Originally Posted by hot ss

if you can prove the mass of the 21 and tire is equal to or less than the stock 20....you are correct. rotating mass, my friend. the fronts wont matter. this is why alum driveshafts are so popular now with manufacturers. the bigger the rim, the less tire footprint on the ground, which also means less traction--but corners like the devil owns it--to a point.
rotating mass robs torque.

So it won't rob the HP, but only the torque?

[uke]

Originally Posted by irpq11

So safe to say that my 21" wheels as opposed to the stock 20"ers shouldn't be the difference of 1.5 secs to 60?

So it won't rob the HP, but only the torque?

I don't think 1 inch will make that big a difference, even though you're not figuring in the weight as well.

On your other question, horsepower is a function of torque x rpm, so yes less torque in this case means less horsepower.

[ssdavidw]

Just found this thread. I have a Camaro on order with the L99 due in later this month.

I'm coming from a huge truck with 22" wheels, without taking the Camaro to the track how can I tell if my car is running slow?

[SGOS252382]

Originally Posted by ssdavidw

Just found this thread. I have a Camaro on order with the L99 due in later this month.

I'm coming from a huge truck with 22" wheels, without taking the Camaro to the track how can I tell if my car is running slow?

The best way is get it dynoed or take it to the track. If the weather is nice
(cool and low humidity - near sea level track) it should run low 13s @ 106+. It should dyno around 320 rwhp.

But in the summer heat, it might not run as fast (mid to high 13s).


From what I've seen, most of the L99's are running good. So I really wouldn't be worried at all. But I would suggest driving it pretty hard with a short break in period. My car only has 400 miles on it and I've been driving it pretty hard from day one. And my car seems to be getting faster and faster every day.

[PQ]

Originally Posted by ssdavidw

Just found this thread. I have a Camaro on order with the L99 due in later this month.

I'm coming from a huge truck with 22" wheels, without taking the Camaro to the track how can I tell if my car is running slow?

Track or dyno like SGOS252382 said. Most L99s are fine.

Originally Posted by uke

I don't think 1 inch will make that big a difference, even though you're not figuring in the weight as well.

On your other question, horsepower is a function of torque x rpm, so yes less torque in this case means less horsepower.

Ok, just so you know, the total diameter of the wheel and tire on the 21s are the same as the 20s. The 21s have a thinner tire. Make a difference?

[rayhawk]

Originally Posted by irpq11

Track or dyno like SGOS252382 said. Most L99s are fine.

Ok, just so you know, the total diameter of the wheel and tire on the 21s are the same as the 20s. The 21s have a thinner tire. Make a difference?

So... did you ever verify the iphone readings? Is your car running better now?

[topgun1]

Originally Posted by uke

I think the easiest practical steps you can take to pinpoint the issue are:

- if you still have them, put your stock wheels back on and see if there is a difference

I would be very interested to see the results of the L99 with the stock wheels.

[PQ]

Originally Posted by rayhawk

So... did you ever verify the iphone readings? Is your car running better now?

Been raining. Can't get a good run. Supposed to rain for the next week.

[Paul]

http://www.ethanolrfa.org/resource/facts/engine/

here is a web site for facts about alcohol in your fuel....ethanol is 113 octane by itself so it would keep your car from detonating not create it

[Rockets]

Originally Posted by Arioch

Although my car doesnt seem to have performance issues (2SS A6), I'll admit its been a long time since I've driven a V8. So I might be wrong. I'd have to test it at a track to be sure. But right now I'm still in the break-in period and babying it.

However I will say that I've had some issues with the car making a knocking or pinging noise occasionally from the engine compartment. At first I was concerned that maybe it was something to do with the oil, but I checked it and it was full. So I think the issue has something to do with bad gas.

I've been filling up at Cheveron a lot and regardless where I go I've been getting premium. I can only find 91 where I live. It's also hot here (110).

In any event I'm going to use a different gas station chain to see if it resolves the issue. If not I'll mention it when I take the car in for the first oil change at 1500.

Different Fuel from different Dealers can make a difference.

GM rates using octane rating of 93 in V8

My bro have a vet and only Shell Gold would not make the car ping and was the best perfomer for his vet

I have the L99 and I think the car has Mega power and its fast too

[O2BQIK]

Originally Posted by irpq11

Ok, just so you know, the total diameter of the wheel and tire on the 21s are the same as the 20s. The 21s have a thinner tire. Make a difference?

Yes it does, in more than one respect:

1. The larger wheel/tire combo will be heavier, as stated above.
2. The metal wheel is heavier than the rubber tire, so by using a larger wheel with the same overall diameter, you're moving mass further toward the outside, which increases the effect of rotational mass mentioned above.
3. Thicker sidewalls are more flexible and (everything else constant) would provide better traction from a stand-still.

I seem to remember you saying months ago that you would get both the stock 20's and the 21's. If you did, you might consider running both at the track when you go so that you can know for sure. I'm not saying your car isn't down on power, but you should expect some performance loss due to your choice of wheel.

[PQ]

Originally Posted by O2BQIK

Yes it does, in more than one respect:

1. The larger wheel/tire combo will be heavier, as stated above.
2. The metal wheel is heavier than the rubber tire, so by using a larger wheel with the same overall diameter, you're moving mass further toward the outside, which increases the effect of rotational mass mentioned above.
3. Thicker sidewalls are more flexible and (everything else constant) would provide better traction from a stand-still.

I seem to remember you saying months ago that you would get both the stock 20's and the 21's. If you did, you might consider running both at the track when you go so that you can know for sure. I'm not saying your car isn't down on power, but you should expect some performance loss due to your choice of wheel.

Sweet. Yes I still have the 20s. Even my damn weekends are booked with stuff though.

I will be able to go to the track on the 25th. But that is my only free weekend til August 22nd. Guess I better make sure to make it. Oh and if it rains, guess I just won't get a quarter mile time but just stick to 0-60 times on the road with the iPhone.

[rpepka]

Originally Posted by uke

Errr...based on past experiences on this sort of issue, both in person and hearing from others, I wouldn't hold your breath on that. Especially if it's only a few cars having the issue. I would definately look into the gas issue first. What octane rating are you running in the car?

And besides, stuff not working efficiently is just a good excuse to mod and UPGRADE! I think a performance tune is in your future




haha, thanks. I'm definately no expert though, I just picked up on info in figuring out what I've broken on my cars over the years.

I actually became intimately familiar issue with KR issues when I got my Grand Prix GTP, which are KR monsters. Fortunately, the GTO doesn't have nearly the same issues as the GP, though it can still be a factor.

Assuming everything working right, I'd expect a 400hp engine to be putting down about 340-345 rwhp on a dyno, so something is definately up with your car only making 305 (that's stock 5.7 LS1 territory). Rule out the easy stuff (gas) and move on from there.

93 octane here.

[rpepka]

Originally Posted by ssdavidw

Just found this thread. I have a Camaro on order with the L99 due in later this month.

I'm coming from a huge truck with 22" wheels, without taking the Camaro to the track how can I tell if my car is running slow?

Buy a stopwatch