MyE28.com

I was so excited to dyno the 745i today in 28F temps. I was mortified to find the dyno was indoors at 68F. This cost a few psi so the pull was at an honest 1 bar (14.5psi) and 68F. Ported/Polished cyl head and huge intercooler obviously helped it pull on top. Not bad for a little SOHC 3.2L





[Edit by TCD on [TIME]1110424997[/TIME]]

Sooooo Niiiiice.... Want to touch the hiney! (@)

Wow, that's really impressive! The guy you mentioned the other day who compared your car to a Z06 wasn't that far off, was he?

What do you suppose causes that little dip at 4900 rpm?


[Edit by stuart in mn on [TIME]1110414035[/TIME]]

[QUOTE="stuart in mn"]Wow, that's really impressive! The guy you mentioned the other day who compared your car to a Z06 wasn't that far off, was he?

What do you suppose causes that little dip at 4900 rpm?

[Edit by stuart in mn on [TIME]1110414035[/TIME]][/QUOTE]

Just a little rich to the tune of 10.81AFR. That dip respresents ~12rwtq lost. I didn't want to retune the car for 68F since it was 28F just outside the door. Ref the Z06. The car was probably making -360rwhp outside with the colder temps and additional 2psi of boost that comes with the cooler weather.
Todd

[Edit by TCD on [TIME]1110415265[/TIME]]


[Edit by TCD on [TIME]1110415359[/TIME]]

All I can say is WOW!

Great numbers Todd!

Damon in STL

Very nice, I like that torque curve alot In as far as the discussion on how this car would fair against a stock E39 ///M5, just some comparison,

RPM ///M5 745it
2500 145hp 65hp
3000 175hp 100hp
3500 210hp 170hp
4000 235hp 230hp
4500 260hp 260hp
5000 280hp 280hp
5500 305hp 325hp
6000 320hp 330hp
6500 325hp 312hp
7000 330hp NA

First, 0-60 I believe is no match, the E39 ///M5 will out class the old 745i with better suspension, traction(traction control DSC) and tire size off the line and during shifting. The quoted spec for the ///M5 by almost all the mags that tested it is 5.2s. I don't believe a E21 can do this unless there are serious mods to the car. Even given the almost 400lbs less the E21 weighs

The 1/4m, I'm not so sure, this may be a good race, as the weight difference may be more of a factor. The ///M5 is quoted as a solid 13.5s. I bet this 745i may do that?

Rolling start at say 15mph and accelerate for say .....20 seconds, Its unclear what aerodynamics play here. Is the ///M5 that much more efficient at high speed as to negate the weight differnece? Not sure. Id like to see this race too.

Now, with that said, the E21 cost Todd 1/3 the price of an E39 ///M5, and it's almost as fast, thats pretty special......

RussC

[QUOTE="russc"]Very nice, I like that torque curve alot In as far as the discussion on how this car would fair against a stock E39 ///M5, just some comparison,

RPM ///M5 745it
2500 145hp 65hp
3000 175hp 100hp
3500 210hp 170hp
4000 235hp 230hp
4500 260hp 260hp
5000 280hp 280hp
5500 305hp 325hp
6000 320hp 330hp
6500 325hp 312hp
7000 330hp NA

First, 0-60 I believe is no match, the E39 ///M5 will out class the old 745i with better suspension, traction(traction control DSC) and tire size off the line and during shifting. The quoted spec for the ///M5 by almost all the mags that tested it is 5.2s. I don't believe a E21 can do this unless there are serious mods to the car. Even given the almost 400lbs less the E21 weighs

The 1/4m, I'm not so sure, this may be a good race, as the weight difference may be more of a factor. The ///M5 is quoted as a solid 13.5s. I bet this 745i may do that?

Rolling start at say 15mph and accelerate for say .....20 seconds, Its unclear what aerodynamics play here. Is the ///M5 that much more efficient at high speed as to negate the weight differnece? Not sure. Id like to see this race too.

Now, with that said, the E21 cost Todd 1/3 the price of an E39 ///M5, and it's almost as fast, thats pretty special......

RussC[/QUOTE]

It'll take an e39 M5. Slightly more power and 400lbs lighter. In a drag race th engine will never see less than 4000rpm. Thiose lower rpm HP numbers are misleading for the 745i. The dyno operator didn't go full throttle until 2300rpm.
Todd


[Edit by TCD on [TIME]1110422106[/TIME]]

Not to nitpick, but the 745i is an e23. The e21 is the '76-'83 3series.



[Edit by Velocewest on [TIME]1110430162[/TIME]]

Todd,

Good numbers! 360 RWHP is hard to beat for running 16.5 PSI! Add another 100 HP to that for the 22+ you're running on the 535i, right? That's insane!

Good job, T!

Cool Beans! And that is with a 3.2L and Moronick ECU managing it. Looking forward to seeing what you 535i will do with the MS.

I have not seen my car for over a week. I have a three day weekend coming up and will spend a solid day with it. Hope to get just about all of the mechanicals installed.

I am also buying a new car for the family tomorrow, the Audi A4 is just too small........it's German of course, more to follow.



[Edit by Duke M535Ti on [TIME]1110443236[/TIME]]

Great numbers Todd! I gotta get that boost controller now.

Again, from standing starts I'm not so sure. Now were taking stock tires, and the car sits now and not drag slicks! My point is the ///M5 has way bigger tires, and will launch much better and with more consitant launches. Plus, the ///M5 power band is a little bigger. While your shifting, he may still be pulling to 7k RPM(Im guessing on this one).

Ill use your 535i 1/4 times as an example. You were able to achieve a 13.5s. In theory the ///M5 will do this all day(at least thats what the testing at Edmunds.com said). I bet the 745i will not go as fast as your 535it, right? your 1/4m times on the 535it was with drag slicks if I recall properly?

Anyway, I'm not trying to denergrate what you've done, just being the devils advocate for a lively conversation

RussC

[QUOTE="russc"]Very nice, I like that torque curve alot In as far as the discussion on how this car would fair against a stock E39 ///M5, just some comparison,

RPM ///M5 745it
2500 145hp 65hp
3000 175hp 100hp
3500 210hp 170hp
4000 235hp 230hp
4500 260hp 260hp
5000 280hp 280hp
5500 305hp 325hp
6000 320hp 330hp
6500 325hp 312hp
7000 330hp NA

First, 0-60 I believe is no match, the E39 ///M5 will out class the old 745i with better suspension, traction(traction control DSC) and tire size off the line and during shifting. The quoted spec for the ///M5 by almost all the mags that tested it is 5.2s. I don't believe a E21 can do this unless there are serious mods to the car. Even given the almost 400lbs less the E21 weighs

The 1/4m, I'm not so sure, this may be a good race, as the weight difference may be more of a factor. The ///M5 is quoted as a solid 13.5s. I bet this 745i may do that?

Rolling start at say 15mph and accelerate for say .....20 seconds, Its unclear what aerodynamics play here. Is the ///M5 that much more efficient at high speed as to negate the weight differnece? Not sure. Id like to see this race too.

Now, with that said, the E21 cost Todd 1/3 the price of an E39 ///M5, and it's almost as fast, thats pretty special......

RussC[/QUOTE]

[QUOTE="TCD"]It'll take an e39 M5. Slightly more power and 400lbs lighter. In a drag race th engine will never see less than 4000rpm. Thiose lower rpm HP numbers are misleading for the 745i. The dyno operator didn't go full throttle until 2300rpm.
Todd

[Edit by TCD on [TIME]1110422106[/TIME]][/QUOTE]

If I still have it in April, I'll amke a trip to the dragstrip.
Todd

I WOULD ask the E39 M5 can launch consistently with a manual transmission when the 745i has an auto, BUT Todd's car is obviously not a standard 745i, having a 5-speed and all.

I side with Russ on this one, but only because Todd's 745i has a stick. If it had an auto, I would change my position. IMHO, Russ is right about the modern suspension and the much wider tires, but I think that, if the 745i had an auto, things would be different, especially if you raced 3 or 4 times, because the 745i would get a much more consistent launch as opposed to the 6-speed M5.

but that depends on how experienced of a driver is behind the wheel of the 5-speed... when i go to the drag strip in my 535i (5-speed) I consistently run 16.2's-16.4's when it's cold and add about a second to that time when it heats up in the day... but i think an experienced driver would have a better chance in a manual. the auto may be more consistent, but IMO it's consistently slower than what a good driver could do in a 5-speed.

Bryan


[Edit by bmwfan2304 on [TIME]1110904050[/TIME]]

You're right that a good shifter -- meaning driver, not shift lever -- can properly launch a manual transmissioned car better than a bad shifter. However, there's absolutely no way that you can be as consistent with a manual transmission as often as you can be consistent with an auto. You can get very close, I'm sure, but one slipup in the clutch operation on the launch or a slipup on one of the two or three shifts -- depending on gearing -- you have to make during the quarter and that consistency is out the window. With the auto, you just power brake it to a certain RPM and let off when the light turns green. After that, you just hang on and watch the ET.

This may be comparing apples to oranges since the 60s era manual transmissions were archaic compared to the 80s - millenium era, but you see many more automatic Novas, Chevelles, etc out there running the strip than you do manuals. Once again, it could be comparing apples to oranges, but I think they prefer the auto anyway.

Damn.

Bump
Mmm,
I looked for 4 minutes and found Todds thread

RussC

^well when i searched 745i dyno i got 0 results. Then i just searched dyno and got like 20 pages...

Ok,
Heres the Todds 733i turbo dyno with the b33 cam



RussC