nelson tune question

[mopower440]

First i have a 1999 silverado with 4.8. I want to order a tune. They say the 1999 trucks had a crappy pcm as it was slow. If i order a tuned PCM from you will it be on another crappy 1999 PCM or will it be on a better newer one?
Next, I am debating between a 91 octane tune or the dual tune 87-91. Now, If i go with the dual tune, will it still perform as well when i am running 91 octane fuel as it would if i did just a single octane 91 tune? I would like to do the dual tune just in case i ever am short on money and can only use 87 octane, BUT, when i can run 91 octane, i want all the performance possible. Seems like it should be the same as long as im running the high octane but seems like a few people are saying the 91 octane tune does better than the dual 87-91 octane tune..Dont know why it would tho as long as im using the high octane, should do the same.. Let me know as im ready to order.

[ducky]

I would just go ahead and do the 91 octane tune. You won't want to worry about getting an 87 tune and it being slow, and to be quite honest, it's really only like $3-$4 difference in gas for a full tank of 87 vs. 91 octane. Do the biggest/best tune.

[mopower440]

so why isnt the 91 tune the same as the 87/91 tune as long as you run 91 octane gas?
Not doing the tune to make it fast, just trying to get more useable power out of it. I tow a 3500 pound boat and it doesnt like it. even when not towing, its hard to use the cruise control because every teeny hill i come to it downshifts to get up it. Hoping a tune would help at least a little with this 4.8 not having any low end torque..

[Erica@NP]

so why isnt the 91 tune the same as the 87/91 tune as long as you run 91 octane gas?
Not doing the tune to make it fast, just trying to get more useable power out of it. I tow a 3500 pound boat and it doesnt like it. even when not towing, its hard to use the cruise control because every teeny hill i come to it downshifts to get up it. Hoping a tune would help at least a little with this 4.8 not having any low end torque..

We cannot tune for 87 and 91. We can only do a dual tune for one step up or one step down. So you can either go with an 87/89 tune or a 89/91 tune. There is a high and a low octane table in the ecm so it will adjust depending on what fuel you are running. just make sure whatever grade of fuel you have us tune for is what you are planning on running the majority of the time.

As far as gains i can kind of give you an idea of what kind of HP and TRQ gains you are looking at gaining are pretty simple. With our custom tuning you would be looking at horse power and torque gains of about 30-35 to the wheels as well as torque running 91 and 93 octane. With 89 octane the gains are about 23-28, and with 87 octane gains are about 15-20. As you can see the higher grade of fuel you run the more power you are going to gain.

With the issues you are having with it downshifting too much we can also adjust for that as well. We can set it to where the downshift points are less sensitive. This way when you are towing or just driving around it will take a little more throttle in order for it to downshift to a lower gear. You will just need to mention that to me, or put it in the notes section, when you order your tune.

Email me at erica@nelsonperformance.com if you have any other questions at all. I will help you out any way i can.

[mopower440]

ok Erica thanks. I am kinda confused on how much TM to have you remove..I dont want to change the shift points or firmness, will the amount of TM removed affect that?

[Erica@NP]

ok Erica thanks. I am kinda confused on how much TM to have you remove..I dont want to change the shift points or firmness, will the amount of TM removed affect that?

Removal of the TM will not affect the firmness of the shifts or the shift points. Basically the TM that GM puts into the vehicle simply limits power to the drive train under aggressive driving. That causes a lack of throttle response. By removing a percentage, or all of the TM you typically will get better off the line and WOT throttle response.

[mopower440]

How much is safe to remove in my application? Being its only a 4.8, and they use the same tranny for the 5.3 which is more powerful, do you think it would be ok to remove it all? just dont want to tear up my tranny..

[Erica@NP]

How much is safe to remove in my application? Being its only a 4.8, and they use the same tranny for the 5.3 which is more powerful, do you think it would be ok to remove it all? just dont want to tear up my tranny..

Typically for a stock transmission we remove about 60%. If you decide to do a shiftkit and or servo or a built transmission then we can remove 100% for you.

[mopower440]

Well, i ordered the tune, just hope it helps this turd..lol

[Crazy Blu]

You'll be incredibly happy! Every thought of gears tho to help with towing? Is it 2wd or 4wd? 3.73s would help a lot. Sounds like you just drive it and not looking for a race truck or I would suggest 4.10s or lower.