Stupid tuning question.

I have the Powerdyne SC 6 lbs kit (only made 5 psi) which included the FMU and Superchip tuning. I have since changed the pulley to the next size and get 7.5 lbs of boost at 5,000 rpms. My current problem is that the truck feels sluggish just off idle then pings from 5 psi up to the 7.5 psi max. I checked my FMU, seems I have the 12:1 calibration. I am also running a 180 deg tstat and water injection triggered at 5 psi to suppress the detonation.

Is there a way to tune the truck (small tweaks) with out ls1edit or having a shop custom dyno tune? If I have to have the custom dyno tune, is there anyone near Austin, Texas? What would I expect to pay for the tuning?

Thanks!

 

Another question. I was looking at tbyrne's website and noticed that he sells a MAF translator, Timing Tuner, and the Predator programmer. All of these can adjust timing and fuel mixtures, with the MAF translator being the cheapest ($190) and the predator the highest at $420. Does anyone here have any experience with these products?

Thanks!

 

Ok, maybe a little more info would help you guys. With the basic kit install (5 psi) I had zero pinging except for an occasional ping near redline (5,200 rpms). Later I installed the smaller pulley and gained about 2 psi (now at 7 psi). I did no tuning, just added a water injection system (didn’t want an intercooler). Now the truck has better SEAT OF THE PANTS throttle response and power. I now have a light pinging under moderate load (my wife can not hear it) and heavy pinging above 5 psi (water injection OFF). With the water injection ON (trigger set at 5 psi), I have still have the light pinging under moderate load, and LIGHT pinging above 5 psi. Now here is the big question. Is the pinging because the fuel mixture is now too lean (more air flowing through)? If so, would a MAF translator be a quick and easy fix?

P.S. My track times are a little worse with the extra boost. My best time with the basic kit (5 psi) was 15.38 sec, and my best with the new pulley (7 psi) is 15.42 sec. Temperature was about the same both times.

Thanks again!

 

Well, you know where pinging comes from. What octane are you running. I know powerdyne recommends a minimum of 92 or 93 octane. When I increased the blower speed on my toyota, I had the same thing, pinging only at high revs. It all came to octane or negative timing. When I would use a boost of 3 octane, and get my octane from the 91 max that you can get out here in vegas to 94, mine went away. I did not want to always have to use 94 octane, so I had it tuned for $350, then it did not nock, but I lost power. I ran a 14.4 with 11psi, but only got 14.9 since retuning it. It is the higher compression that is cuasing the pinging, or predetonation. Your compression level with the stock motor is 9.5 to 1, then when introducing 6lbs of boost to that, it raises it to 14.4 to 1. Still fine with 92 octane gas under most cases. 8lbs of boost indicate a 15.2-15.4 to 1, that is some major compression wether anyone will admit it or not. You can go easily 9lbs before having to even think of your headgaskets on these newer vehicles. The 80s cars used different gaskets and would blow them with as little as 7psi. At 15.3 to 1, that gas wants to blow up immediately when being compressed since compression equals heat, just like the intake air is heated as much as 180 degrees with the supercharger, that is why intercooling is so much better. Now if the air was intercooled, that would drop it as much as 100 to 160 degrees depending on your intercooler, which would lessen the temps when the cylinder is compressing it some more, you get rid of the pinging with that, or higher octane, that is less flammable, will help also, try the octane boost first. Third detuning, or dropping the timing on the higher revs will help to a degree also, like mine, but it depends on how high your boost is.

For every 1 level of compression increase, the average piston makes about 5 horsepower more. When you get higher compression or raised heat, only higher octane will truelly get rid of predetonation. The higher the octane you use the lower the horsepower made, but the loss of power is less substantial than the increase made by the compression. So technically you should get 200hp from a 6 lb boost set up, but since to run it without detonation, you use 92 octane, that makes about 2.1 horsepower less per cylinder. Thus in turn you only get a true 140 horsepower from the supercharger, and less than that depending on the charge intake air. These numbers are only good for ambient air temps, from my motor building days. Now supercharging is better than building a high compression motor, since supercharge only happens when you are mashing the gas, so for most driving, its a tame motor, then mash it and it becomes a high compression race motor! Motors with constant 14 to 15 to 1 compression ratios, never lasted that long, until recently with all the heavy *** componentry that they use in motors now.

So this is a long way to say, use higher octane!

 

Oh yeah, forgot to tell you that what reducing the timing does, is lessen the total amount of air and fuel that can get into the motor before the spark goes off, so you actually get less power, but less gas and air that can detonate when under full throttle. Your motor, always makes the same compression, but runs nice when giving little gas, and puts a lesser explosion in the cylinder. Max effeciency or power is only made when flooring it, that is why you get the ping under moderate load, or WOT. The Diablo tunner is supposed to be able to give you plus or minus 10 degrees of tuning throughout the rpm range, but I heard that you had to have it programmed on a laptop or home computer to do that. Now on their website I believe I saw a cable that you can buy to plug the Diablo into a serial port on the computer, so that makes sense that you can program the timing yourself. Am not to sure on that!