stealth_GT

for as long as I had it, It had great acceleration off the line and mid-top end.. the only problem I felt was the cruising speed- it felt really slow even though the tach would read 60 or 80 mph. I passed a few electronic speed limit posters and every time I passed at 45 or so mph according to the tach, but on the posted limit scanner it read a measly 30-31.

The rpms are at 1500@60mph.. kinda low for 4.10s (?) I would think.

I was pulled over yesterday night for impeding traffic, according to the speed gun I was doing 40 in a 65 lol. Wanted to make sure I was not drunk.. I wasn't, I was sober. I knew I was 'going 60' because the speedo said so, even though it did feel slow.


I was left go and told to drive faster.. so I did.

I run the exhaust cut outs open as well, not sure if that messes up the speedo or not.



I reloaded the Brenspeed tune today and immediately I could feel a difference. 60 felt like 60, 40 felt like 40 and so forth. Even picked up speed alot faster and shifted right.

What the hell is going on? Did I get a junk tune?? Been running it for months...

(O_o)?!

RHuckster

lol, go in & program the revolutions per minute of the tire that fits your tire size. I'm guessing you changed tire size or it was a mistake in programing. No big deal, easy to fix with your programmer. Since it looks like you changed your gears after re-reading your post you need to change that as well in your programmer, easy to do as well.

Rick

stealth_GT

hmmmm.. that's odd. They are all 4.10 tunes. I have 2 from Bama ( 1 with a lower 1st gear for traction, the other full race tune) and a standard Brenspeed 4.10 tune. They all have stock tire sizes on the tune as well.

RHuckster

So when you go in to setup your tuner once its connected to the obd II port it shows the correct gear set? Also find out the correct tire rev. for your tires & set that while your in there. Maybe its a glitch, maybe a mistake..they do happen.

Rick

RHuckster

I had Doug do my tunes for my Ranger before I bought the stang & the tunes(all 3) had a problem, it would die when I put it in gear(auto), he sent me new tunes & I also did the software update needed for my SCT 2 programmer & all was well again.

Rick

stealth_GT

I can only go by what he sent me and so far it does 'show' that everything is correct; gears, tires etc. It's a helluva glitch, because with the Brenspeed tune (corrected tire ratio) it pulls HARD throughout the powerband. The bama tune would show that it was accelerating ie the tach, though the butt dyno could tell it was no where near 80 mph.. or even 110mph.

Weird.


I'll shoot him an email on monday..

thanks for your help!!



PS

I knew something was up at the track, because it would show me trapping at 120mph on the tach but only 103 on the actual timer board...

mustangtestuser

Do not trust the stock tire rev per mile. My original SCT tune was way off after my gear change. I couldn't figure out what it was until I did a little testing. It turns out the "stock" rev per mile was off. I was probably driving around going under the speed limit the entire time I had the tune! When I changed gears I started examining my speed more closely to make sure all was well, which was the only reason I discovered the problem.

When I got my Bama Chips tune I manually entered the rev per mile to avoid any possible problems.

I eventually found out that the stock speedometer would read 3 mph high at highway speeds compared to what the computer was reading. I think the needle is a little off from Ford. No big deal. It just shows the hassle I went through to get all this corrected.

I'd do some followup testing with a GPS. Just remember that your speedometer isn't accurate at low speeds and the GPS is only accurate at best at stable speeds.

If you don't know your rev per mile, then you may want to start at 770 that will get you pretty close if your tires are the same diameter as stock. Check the manufacturer first for the number, then try Tire Rack.

stealth_GT

3 mph over or under is not as bad as 20 or so mph under lol...


I have the Brenspeed tune on there now so it's corrected. I'll get a new reworked Bama tune later. I was stunned that that happend, I always thought (because of the speedo being off) the Bama tune was so much more effective because it would pick up speed so quickly lol.. so when I was going 80 ,I was actually going 60 lol.

stealth_GT

wow. I just did a few test funs with the Brenspeed tune with the O/D both on then off.

Well, it certainly feels different with the correct tune. The speedo is reading correctly, but damn if it dosen't feel SLOW lol..

with the BAMA tune and OD off, I'd pin the needle and top out the car in a heart beat, now it feels like it's slower, though because the speedo was off before, whos to say the tach wasn't off as well.. maybe it was topping out at 120 instead of 145 before with the Bama?? who knows..

from a roll at 60 it's like a brick lol.. then again, the only mod I have is the CAI, and cut outs so it's not like I am modded to hell or anything..

Gene K

Try manually setting the parameters for Tires - 770 rpm (Close to 768 as you can) and gears for 4.10 (instead of stock) to see what you get. Sounds to me like Doug set your gearing at 3.31 in the tune.

Gene