OH YEA, Troyer Dyno Tune
Suspended
Joined: Nov 2004
Posts: 17,079
Likes: 0
You and OP of this thread were similarly modded with intake, exhaust, and a tune. You put down 241 to the rear wheels and the OP had 249 and both had the same RWTQ. I am going to go out on a limb and guess that the OP has 3.5 AF1 and magnaflow catback. The magnaflow flows better up top due to its straight through design which is where the other ~8rwhp is, assuming he went with the maggy
The size and weight of the tires does not matter on the dyno, much like gears. Do you know how much RWHP you gain by going from say 3.55's to say 4.88's? You actually gain 0 RWHP and that is because the output from the engine has not changed, you will gain a ton of speed but not more rwhp. Larger wheels and tires just work as the negative to that and don't effect your RWHP but slow you done a ton.
The size and weight of the tires does not matter on the dyno, much like gears. Do you know how much RWHP you gain by going from say 3.55's to say 4.88's? You actually gain 0 RWHP and that is because the output from the engine has not changed, you will gain a ton of speed but not more rwhp. Larger wheels and tires just work as the negative to that and don't effect your RWHP but slow you done a ton.
Yes, tires do make a difference on the dyno. Why don't you give Justin or Mike a call and ask them? I can assure you that both will tell you when you're talking about a 37" tire, there's a big difference. We aren't talking about gears but you are correct as they do not effect numbers. The wheel/tires are ultimately the last thing of the vehicle before that power reaches the dyno. It's extra rotational weight, we're not talking about the diameter of the tire bu the weight. The weight is what's causing a loss.
haha
Technical Article Contributor
Joined: Dec 2006
Posts: 1,584
Likes: 0
From: Sask. Canada
What are you talking about? We didn't put down the same dyno numbers. The OP said he put down 270 rwhp. I put down 240+ rwhp. I will say this though the 3.5" AF1 and the Magnaflow flow a lot better than a S&B intake and true duals with Flowmaster Mufflers.
Yes, tires do make a difference on the dyno. Why don't you give Justin or Mike a call and ask them? I can assure you that both will tell you when you're talking about a 37" tire, there's a big difference. We aren't talking about gears but you are correct as they do not effect numbers. The wheel/tires are ultimately the last thing of the vehicle before that power reaches the dyno. It's extra rotational weight, we're not talking about the diameter of the tire bu the weight. The weight is what's causing a loss.
Yes, tires do make a difference on the dyno. Why don't you give Justin or Mike a call and ask them? I can assure you that both will tell you when you're talking about a 37" tire, there's a big difference. We aren't talking about gears but you are correct as they do not effect numbers. The wheel/tires are ultimately the last thing of the vehicle before that power reaches the dyno. It's extra rotational weight, we're not talking about the diameter of the tire bu the weight. The weight is what's causing a loss.
I just have the dyn chart from yeaterday. I have other things like and exhaust and cold air intake and tune. Last time with my 33s and 20s I got 249 rwhp and 302 rwtq which is ok but my truck was being a biatch on the dyno. With the headers and coilpacks mike wipped her into shape on the dyn (at about 8pm at night) so Id say i got 25rwtq or so from the headers, they sound awesome and made the torque flat. The truck pulls hard now. Its awesome
Technical Article Contributor
Joined: Dec 2006
Posts: 1,584
Likes: 0
From: Sask. Canada
Because I already had that discussion with "vitviper" (a tuner) over at bamachips a couple years ago
Suspended
Joined: Nov 2004
Posts: 17,079
Likes: 0
Think about it. What you're saying makes zero sense. How would rotational mass not effect rwhp. The crank hp would be the same but the rwhp is going to be different. Those axles, gears, driveshaft, transmission all have to spin more weight with bigger tires which would reduce rwhp. I'm going to have to agree to disagree with you on this one because it seems like you're stuck in your belief as I am (.. and others). 
Technical Article Contributor
Joined: Dec 2006
Posts: 1,584
Likes: 0
From: Sask. Canada
Think about it. What you're saying makes zero sense. How would rotational mass not effect rwhp. The crank hp would be the same but the rwhp is going to be different. Those axles, gears, driveshaft, transmission all have to spin more weight with bigger tires which would reduce rwhp. I'm going to have to agree to disagree with you on this one because it seems like you're stuck in your belief as I am (.. and others).
Suspended
Joined: Nov 2004
Posts: 17,079
Likes: 0
Of course the difference between a 17" wheel and 15" is going to be minuscule. I've talked to Justin about this before and there is a loss. Say on my Mustang, my 20s vs factory wheels/tires is a loss of about 2-3 rwhp. However HEAVY 37" tires and HEAVY 20x10 wheels are going to make a big difference. I'd like to know how you believe that it wouldn't effect the numbers though? Do you have a reason?
Technical Article Contributor
Joined: Dec 2006
Posts: 1,584
Likes: 0
From: Sask. Canada
Of course the difference between a 17" wheel and 15" is going to be minuscule. I've talked to Justin about this before and there is a loss. Say on my Mustang, my 20s vs factory wheels/tires is a loss of about 2-3 rwhp. However HEAVY 37" tires and HEAVY 20x10 wheels are going to make a big difference. I'd like to know how you believe that it wouldn't effect the numbers though? Do you have a reason?
If it really is the case that those 20s were really holding your truck back that much than I would have to say that vmp puts down a LOT more power to the ground then Troyer does (assuming they both use the same type of dyno, mustang or dyno jet). Both of them are relatively close to the same elevation but the warmer temperatures and higher humidity in Florida would hurt his dyno numbers.
I am going to answer your question with a question. Do you think that your 37s vs 33s, S&B vs 3.5 AF1, and magnaflow vs fartmaster only equates to 8whp and the SAME torque with your theory?
Senior Member
Joined: Oct 2005
Posts: 618
Likes: 0
From: Spring/Woodlands, Tx.
is this a 4.6l or a 5.4l? either way thats really really good.
Thats just about what my truck makes and urs is N/A!
and yeah, tire size and stuff does matter.
look at this guys truck, very nice truck - https://www.f150online.com/forums/sh...d.php?t=329403 but his tires and all that rob his dyno numbers big time.
Suspended
Joined: Nov 2004
Posts: 17,079
Likes: 0
The difference was about 10lbs per wheel on a 2500lb car that came from the factory with 130 crank hp.
If it really is the case that those 20s were really holding your truck back that much than I would have to say that vmp puts down a LOT more power to the ground then Troyer does (assuming they both use the same type of dyno, mustang or dyno jet). Both of them are relatively close to the same elevation but the warmer temperatures and higher humidity in Florida would hurt his dyno numbers.
I am going to answer your question with a question. Do you think that your 37s vs 33s, S&B vs 3.5 AF1, and magnaflow vs fartmaster only equates to 8whp and the SAME torque with your theory?
If it really is the case that those 20s were really holding your truck back that much than I would have to say that vmp puts down a LOT more power to the ground then Troyer does (assuming they both use the same type of dyno, mustang or dyno jet). Both of them are relatively close to the same elevation but the warmer temperatures and higher humidity in Florida would hurt his dyno numbers.
I am going to answer your question with a question. Do you think that your 37s vs 33s, S&B vs 3.5 AF1, and magnaflow vs fartmaster only equates to 8whp and the SAME torque with your theory?
Senior Member
Joined: Apr 2005
Posts: 621
Likes: 0
From: Back Woods of Chester Co PA
Cool, the long tubes are definately the next ( and final ) perf mod here. As far as gears, this thing launches off line now and in all gears, truck operates more within the power band. Next to the tuner, this is the best 'seat of the pants' mod I've done. imo, well worth it. Gears for offline and keeping truck more in powerband, and intake/tuner combo ( and headers soon ) to give it the set of ***** that Ford forgot. I'm staying with the 33" tire size. ( 33.6 " actually ). Not too bad on highways, speed limit is 55 basically everywhere here but on the turnpike and a few other state routes where it is 65. You would have to run up to 35" tires if you were a regular 80mph traveler as it may be a bit much now for some.
Senior Member
Joined: Jul 2006
Posts: 1,052
Likes: 0
Eh...when I went from the factory 18's to the factory 20's it slowed my truck down noticeably driving around. It makes no sense why you wouldn't lose hp on the dyno when it takes a good bit more power to turn a heavier wheel.