I need a tune for a Speed Density system what would everyone recommend. I live near Backstreet Performance in Ohio or should I just go thru Alvin? It is a 383 street motor Pro Action head small solid cam flat top motor with miniram and NO2

 

Get a dyno-tune or better yet a track-tune If possible, a mail order tune is a good starting point when the other 2 options are not available and even then after a mail-tune you will still need a dyno or track tune in order to fine-tune pe mode etc. IMHO

 

Track tunes are good for wide open throttle but are much less controllable, IE you need a wide band O2, data logging, etc. Dyno tunes are good for wide open throttle and should have the wideband. Both are thoroughly useless for driveability, and in fact your driveability tuning will likely mess up your wide open throttle tuning if done after the fact.

To do it right you need to make a first guess that is close, drive the car a lot under varying conditions, data log it, and change it until you get it right, then strap it to the dyno and get wide open throttle right.

Nothing at all against PCMForLess, but if your dyno tuner knows what he's doing, you'll get better results faster. If, however, he just straps it down, runs it on the dyno, tunes WOT, and doesn't touch anything else, you just got ripped. There is a LOT more to tuning than just getting the best track time or dyno number. A proper dyno tune will start long before the car is ever strapped to the dyno. If your changes are extremely radical, you will be better in the long run to buy what you need and tune it yourself.

BTW speed density is a lot more of a bitch to tune at than MAF. Reason being that speed density knows only what you tell it. MAF can always look at the sensor and add fuel accordingly. I've spent many hours driving, data logging, and tuning to get my speed density correct whereas I've only needed to adjust the idle speed on a MAF car that was just as modified. (before anybody jumps by bones on that, it was an 89 MAF car that had no SD tables)

If I was to tune a newer style MAF car that has the backup SD tables I would force it to SD mode until I got it running well, then re-enable the MAF.

 

I'd go with the Dynojet tune.

PCM for less tune my ECM and yes, it runs strong but, I took my LT1 to the dyno jet for a RWHP run and the LT1 generated 279 RWHP @ 5,300 RPM. The guy did four runs and in three of them 279 RWHP but the LT1 just stopped making power @5,300 RPM. We all know factory, the LT1 goes to 5,600 RPM.

Let the guy at the dynojet hook it up. Read this, you get what you pay for.

 

Are you implying that you took a completely stock car and put a PCMForLess tune on it and the fact that it stopped making power at 5300RPM is the tune's fault? Did you dyno it before / after the chip? More than likely your valve springs are shot and you're getting valve float above 5300 and hence the reason it stops making power. I don't care who tunes it, you can't tune out a mechanical problem.