Repo Pilot

VP makes two MS109's. One (109 reg) contains MTBE and the other (109) does not.

The only thing I can find on the difference is it looks like some injectors do not handle the MTBE well.

I have some bolt-on's installed but the car is not tuned.

For those of you who are racing your cars or are otherwise "in the know" - Can the ZR1 handle both fuels? Does one generate more power or does the engine handle 1 better than the other?

Thanks in advance ...

.gearhead.

I run a 50/50 mix of MS109 reg and 93 octane with no issues. I'm not sure that helps, but it's a data point.

Cman01

MTBE is an oxygenate to raise octane levels, if VP has a 109 octane fuel without needing MTBE to get it to 109 octane I would go with that instead if u can get it. MS109 is OOS currently on their site.

https://en.m.wikipedia.org/wiki/MTBE...gas%20stations.

Repo Pilot

Yup. I understand there is a big California lawsuit going on over MS109 being made for the California Market without MTBE. Apparently it tested at 107. Maybe that is why its not available.

I'll just use the MS109reg with MTBE and be sure not to spill it in the process. I was able to get that from the local VP distributor without a problem. So I'm all set :-)

19ZR1

Scanning with HP Tuner I found that all I needed was 95 octane to maintain full timing. I mix Sunoco 100 octane with Ethanol free 92 octane.

Cman01

You've mentioned you are still on the stock ECU (no tuning) so you should be able to just get by with 100 octane VP fuel (whichever one they sell, unleaded). You really don't need or get any more knock resistance using 109 fuel and the ECU wouldn't be able to take advantage of the 109 fuel you put in there anyways.

From the posts uploaded here, the stock ECU can certainly take advantage of putting 100 octane fuel in the car.

https://www.corvetteforum.com/forums...questions.html

Hib Halverson

I found virtually the same result in my accel. testing of 1878 while scanning with HPT's VCM Scanner. I ran a mix of 91-oct and 100-oct E10 Rockett Brand Racing Gasoline. A mix with 95-96 octane eliminated KR.

Cman01

I wonder how the knock resistance is using 94 octane fuel, we have that up here in Canada (it is up to 10% ethanol mixed though). As of a few years ago we have gotten a few Mobil stations (basically enhanced Esso stations) and they have 93 octane (again with up to 10%E). Haven't tried that one yet I've been using the 94 Ultra.

Regular Esso super unleaded is 91 octane with 10%E. Shell is also 91 octane but no ethanol.

ClydeFrog

You’re wasting your money putting 100 or 109 in a car that’s on a stock tune.

BearZ06

You are 100% incorrect-this is a ZR1 not a Z06.

ClydeFrog

Doesn’t matter whether its a Z0 or a ZR. The both come from the factory tuned for 93. You going to try and tell me the ZR stock tune will advance timing to take full advantage of 100 octane?
My ZR is dual tuned & running 100 on the 93 tune doesn’t make a **** of difference.

19ZR1

you are confusing a tune with knock reduction. The factory tune will allow higher timing IF you don’t have KR from running lower octane fuel. I have scans proving this. Think of it this way. The factory tune will allow 19-20 degrees of timing. You may only get 14.5 degrees of that on 93.

MustOBeenYellow2015Z

Just out of curiosity, if the stock ecm is tuned with 19-20, how much timing does the typical tuner put in? If I'm not running cats, can I run leaded VP110? When switching to race fuel do you have to change the type of plug you run?


*Where does everyone get their MS109 from?

ClydeFrog

I’ve been educated & apologies to Bear. I didn’t know the ECM would advance timing that far on the stock tune. My stock tune was gone at 600 miles.

C7&7

It will allow 19-20 with 93 also. There are so many other factors other than just octane. Heat, air temps, altitude, etc. Higher octane fuel does not add power without tuning for it. PIt prevents the car from losing power.

19ZR1

It seems like people get stuck on octane as the holy grail to make HP. Fact is if you can get full timing with 95 octane, anything more than that is just wasted money for no gain. Indy cars ran 20,000RPM on 96 octane as a reference. Equally important is the fuels specific gravity. A light fuel will burn faster than a fuel with a heavy SG. A light fuel requires less timing to make max power since it burns faster. In my testing heavy SG non alcohol fuels work great in the LT5 and I can get 19 degrees of timing even when IAT2 temps are in the 150 range.

BearZ06

Just an FYI for those that may not have seen this in the OM.