12secrd

Buck I agree 100%.

The 87 Tune looks so good I ordered one.

Only thing now is a A/f graph to go along with it.

When it arrives it's straight to the local dyno for a stock vs 87 livernois tune comparison and A/F ratio check.

Chaddafd

Cool, keep us posted

Buck

I never said your point wasn't valid. I already said its obvious the 93 tune makes more power....I simply said I like the way the curves of the 87 tune looks better than those of the 93 tune....And I stand by that.
You need to let the swelling in your head go down a little and take peoples' comments for what they are instead of trying to show off that you have an engineering degree.



No, I want that peak torque number to hold better instead of spiking for a measly 300 RPMs...Basically I'd prefer the 93 torque curve to look like the 87 torque curve....only with higher numbers. Simple as that. Is it possible? Maybe not. I'd assume that with LMS' extensive experience and reputation they had already done all they could to get the best tune possible. SO it is what it is.


Negative. That usually happens when the one with less hp has a good linear torque curve that holds throughout the rpms. Low end torque has little effect in ATV sand drag racing up a hill when you are through 1,2, and into 3rd or 4th gear within a couple seconds and running up the hill at 60-80 MPH (depending on your build). Mid range torque is king in this arena. Again, crunch numbers however you like. Real world experience is what I base my knowledge/decisions on.


So....All things being equal you'd rather have a torque curve that starts out above another curve but then drops down below that other curve mid range while the other one holds steady? I guess we have differing opinions on that then. Everyone I know that knows what they are doing when tuning shoots for that long smooth torque line that holds throughout the rpm range as long as possible. There may be different preferences for different applications but I still hold to my preference.

Buck

Are you going to try to compare it to the 93 tune? Feel wise?

linkin_park_453

Just installed 91 tune! Wow this thing hauls *** now it's like a new truck with the 35" toyos love it!

engineermike

Why make this personal?

Of course, we'd all like to have 450 rwftlb from idle to 6000 rpm, but then we'd have 515 rwhp too. I highly doubt 515 rwhp is possible with only a tune, but if it were I'm sure they would have done it. In the absense of that, give me the 450 ft-lb at low rpm.

Granted, my experience is limited to 1000 hp drag cars, 1000 hp airboats, 300 hp PWC's, outboards, street bikes, and dirt bikes, but something else is going on with your ATV's. Perhaps the higher hp is more likely to break the tires loose. Perhaps less low-end torque allows for more traction. Who knows, without a high speed datalogger, but I might point out that a light weight sand-racing quad is a highly non-typical application. On the road in a 5500 lb pickup, give me as much low-end torque as possible.

Hold on a second, I never said I wanted less anywhere!

David Vizard said a long time ago, that in a heavy vehicle (he was referring to a 3800 lb car), 10 ft-lb of torque down low will be more beneficial than 10 hp up top.

Everyone I know that knows what they are doing when tuning, engine building, or choosing driveline components, wants to maximize low-end torque. This is for drag racing and for towing. I remember when people learned that they could get a huge spike in peak torque at low rpm using high STR torque converters. The LS-cars dropped half a second in the quarter. And try arguing with a Diesel tuner or owner that they have too much low-end torque and need to reduce it in order to "flatten" the curve. They will laugh. I've heard of people not wanting rising torque curves, or torque curves with large valleys, but I've NEVER heard anyone say they wanted less low-end torque, ESPECIALLY in a 5000+ lb vehicle.

Briss929

I agree with engineermike.

The greatest need is when the vehicle passes from stop to motion. A spike torque at low RPM will decrease the acceleration time.

TuxBlackEB

I installed the 87 tune a few hours ago (thanks, Rick for the update). I put about 35 miles on my truck with the 87 tune, and here are my thoughts:

The 87 tune feels PERFECT. Off the line acceleration to 60 is noticeably quicker. Mid-range acceleration felt better, too. Granted, I still have 3/4 tank of 91 (maybe that's a good thing with the 87 tune?), but this tune flat out feels better.

I'd be very interested to see back to back 1/4 mile runs with both the 87 and 91 tunes, but with 91 in the tank for both runs. I know the 87 tuned truck will get it on the hole shot, and cut a better 60' time (it really is that much more noticeably stout from 0-60). The interesting part would be how close the ET's are.

I think both Buck and EngineerMike make good arguments, but from a SOTP standpoint, I gotta side with Buck.

Buck

Excuse me for taking it there. I just always read all of your posts talking down to people when in discussions like these and it gets to me. My bad.

I like how you are attempting to make my points into not wanting or needing low end torque...Not once did I say that. My SIMPLE point was that the 87 torque curve looks better to me. Simple as that. NOT ONCE did I say the 93 tune needed to lose the spike to be a better curve than the 87. It would simply be a lot better within itself if after that spike the torque held better/longer. But it doesnt hold as well as the 87 tune does. And I stand by that. I don't recall ever saying I preferred less low end torque as you elude to. You are pretty good at trying to put words into peoples' mouths. Torque spike aside the 93 curve is a bit better power wise but is not as good entire curve wise to me. END of story. You keep talking numbers and I'm talking how well the tune will perform real world.

Buck

Good to see some real feel associated with the "theory". back to back runs between the two tunes would be good for those that are big into drag racing. But for me It sounds like the 87 is where its at if it drives like the dyno graph says it should.