techmanBDsStang

Hello all. I got my Brenspeed programmer yesterday. I downloaded the 87 tune as my tank is 3/4 full with 87. I took it out for a spin, and definatley made a difference in driving experience. I have the GMS CAI I bought about 6 months ago. The butt dyno on the power is about the same, BUT the response is much better.

Anyways this morning going to work, I noticed when at a light idling, I believe I heard knocking. I will use 91, that was always the plan but wanted to try it out right away so used 91. So I am close to half a tank. I would like to change to the 91 octane to see if the knocking goes away. Can I put in 91 now and change over or should I wait until the tank is close to empty.

Another thought I had was changing to the 89 tune to se if that may help. Any suggestions.

On a side note: A week ago I installed the BMR LCA's and A Arm support. What a great difference the LCA's made taking off. Man I love this car as it is fun to work with.[sm=bounceybounce.gif]

owero01

Put the 91 in now. It will bring your octane average up. It will help with the knocking.

howarmat

Put 91 in the tank but leave the 87 tune in. Once that tank of 91/87 mix is gone then fill up with whatever octane you want and put that tune in.

techmanBDsStang

Thanks for the advice. I will give that a try. Oh, and I am going 91, no doubt about that.

BoidMorphs

I don't understand why your car would be knocking at idle since the spark shouldn't even be advanced. If your tank is 3/4 full with 87 octane gas I'd put in 93 octane to bring the tank closer to your 91 objective. Figure if the tank was 50/50 87 and 93 the average octane would only be 90. You're saying it's 75% full so you need to put 93 octane in NOT 87. I'd still call Brenspeed and askthem what's up because the 87 tune is useless if it's knocking at idle. What makes you think the 91 tune will be any better?

techmanBDsStang

I was going to contact them as well.

And for the record, can't get 93 here.

And this is how it sounds just to be 100% it is a knock. I was sitting at a light, and at first I couldn't tell what it was. It sounds basically like someone is knocking on a door. I never heard this sound before. I was looking around to see who was around. But noticed it at every light.

As far as going to the 91 tune, I was thinking the timing is different because of the 91, so maybe it will be fine at 91, and maybe the timing is a little off in the 87 tune. It is just a thought.

techmanBDsStang

I was also thinking, I put the Live program on my work laptop and want to figure out how to log data. This way if there is any data Brenspeed could use if there were a problem. Any suggestion on what to log from the ECU. I would love to get an A/F ratio monitor but the funds are not there right now.

modular81

Remember now, these cars can spark knock even on the factory tune which is for 87oct. This is stated in the owners manual. Running a performance tune for 87oct could probably make the spark knock worse because of the leaner air/fuel mixture as well. Either run the 93oct tune with 93oct gas if available or a 91oct tune with 91oct gas.This should fix your problem

scrmngt

Sorry guys...as I have read multiple threads regarding tunes, (and threads like these make me hesitant as I have yet to tune), but I have yet to see anyone complain about a knocking. If you ask for an 87 tune...why would you use 91 or 89 ? There should be no magic in this, and if there was going to be a knock, I would have to assume Brent would say, "hey, with this 87 octane tune, you're gonna have a knock unless you use a higher onctane fuel". What I am getting at, is to me, this is not normal and why screw around with 1/2 a tank of this and a 1/4 tank of that...just callBrent and ask him if this is normal and find a solution. I am curious myself on how you make out because as stated, threads like these keep me from pulling the trigger on a tune.

techmanBDsStang

He gives 3 tunes, 87, 89 and 91(or 93 or 92 depending where you live and what you have around).

I only used the 87 like I stated before because That is what is in my tank now. My plan is once this tank is gone, I will go to the 91.