I got some questions for you, im thinking of stepping up to a 6lb lower pulley, im now using a 4lb lower and all my mods are listed below, I live in CA so all I can get here is crappy 91 octane gas, my goal is at least 400 rwhp and 500 rwtq, more would be better, but I would be happy in the 400/500 club. right now im using a superchip flipchip with the 4lb pulley and mods listed below, I bought a used single program superchip from the classifieds, I don`t know what program is on it, but would like to have it reburned for the 6lb pulley and mods listed below and would like to keep the air fuel ratio around 11.7 or so. what would a reburn cost me?, ond what kind of power can I expect with the 6lb lower and mods below?.
also, is it possible to make 400 rwhp and 500 rwtq with the mods I have now with a better chip tune? I like the 4lb pulley but if I need to go bigger I will.

Thanks for your time.

Larry.

 

Hi Speeder,

Sure, we can help you with this, just give us a call.

This is really too involved to go over in proper detail here, so you;ll want to give us a call.

One quick point, and this is of course up to you, but staying at 11.7:1 (first pull) you're giving up power and not gaining any more durability or reliability as long as there is no detonation from too much timing and/or poor fuel quality. With these Modular cylinder heads, they like about a half-point (0.5) leaner A/F's in general as compared to say, the 5.0 & 5.8, in terms of where peak power is at on a dyno. We generally tune them in the 12.0-12.5:1 range. For example, in my 2001 I'm running at 12.3:1-12.4:1, and that's with a 6 PSI lower and a 2 PSI upper, running 17 PSI total boost. The plugs look absolutely beautifully tan, and there isn't a hint of detonation thru the plug scope.

Of course, this is up to you, we're happy to tune it fat if you want it that way.

Using 91 octane will be a concern, and when limited to 91 octane, sometimes I do not recommend using a 6 PSI pulley - well, let me put it this way - I don't recommend running in excess of about 13 PSI total boost (in summertime temps). 8 PSI is stock, an intake kit gets you another 1 PSI, and the 4 PSI pulley gets you 3-4 more PSI, depending on it's actual diameter & the amount of belt slippage. So you're at as much as 13 PSI already, and at least 12 PSI. If the actual BTU content (energy content, which is almost as important as octane level) of the fuel is high enough, you could get away with a 6 PSI pulley.

Your idea of tuning it fatter (and we'd also have to reduce timing) is one way to run more pulley, however, ET-wise you'll usually get a better result using the 4 PSI pulley & a good sharp tune. I don't mean a tune on the ragged edge, I mean a good, sharp state of tune that still protects the motor. A 6 PSI pulley feels great on the street, as you have a good bit more part-throttle torque, but ET-wise, you'd do better with the 4 PSI unit & a sharp tune.

Also, remember that with each successive dyno pull, the A/F's will get fatter & fatter (I.E., 1st run may be 12.3 A/F and the second will be 11.5, etc.), and the PCM will pull out more timing as load peaks; this will continue as you put more heat into the powertrain.

At any rate, I'm getting too detailed myself already for here on the boards, so please do give us a call when you get a chance, & then I can spend some time with you going over this properly.

The bottom line is, we'll tune it however you want it, of course, we're happy to help you meet your goals.

 

Thanks for the information, I run shell gas in my truck all the time, is there gas good quality?, there are also chevron stations here also, is one better than the other?, I will call you as soon as I can to go over things with you.

Larry.

 

Hi Larry,

Well, over the past 3-4 years the reports we get from our customers have generally been that here in the East, Shell can be a fine fuel - I used some recently and my Lightning had no problems with it on my most aggressive program. Out West, it doesn't seem to be doing quite as good a job as it does here in the East.

Usually we recommend using Chevron just about anywhere west of about Texas or so, in the areas that have 91 octane premium fuels. In most cases, Chevron is an excellent fuel among the 91 octane premiums.

However, you may do just fine with your local Shell there, and if it's working well, then there's no need to change it.

The real issue is the energy content (# of BTU's per gallon), as that is at least as important as the octane number. A lower energy fuel won't support the same conditions in the combustion chamber as another fuel of the same octane, but higher BTU's. And of course, you never know what the BTU content is, it's not on the pump, and it a bit of a moving target from one refinery run to the next, though the better companies will keep it within a certain range, as I understand it.

As long as you aren't getting any detonation, and the plugs look good, there's no pressing reason to change from that Shell you're using. If you decide you *want* to change, then give Chevron a try.

Good luck!