MyE28.com

I created some comparison dyno plots. Area under the curve is quite interesting.

Current 535is 348rwhp/395rwtq vs Old 535i at 20psi 353rwhp/418rwtq



Current 535is 348rwhp/395rwtq vs Sweeney's TT 635 at 15psi



Current 535is 348rwhp/395rwtq vs TCD e23 3.2L Big Cam Flowed Head



Current 535is 348rwhp/395rwtq vs TCD e30 at 13psi

How much boost was the e23 running? The shape of the curves are all pretty similar (on that graph), it just doesn't reach the same numbers. The horsepower certainly keeps climbing high though.

I think I need a 1 bar spring now...

Todd,

Very nice torque curves for the current 535i.

Question, what is causing the slight rolloff of the curve @3400 RPM ?? If you could get rid of that small dip you'd have a nearly linear rise in torque right up to the peak torque plateau.

IMO, I'd drop the HP curves. It makes the graphs busy. The only real use I see for the HP curve is to view the HP rolloff after 5252 RPM.

Rich

Rich, that dip is typical of M30 engines... assumed to be a resonance anomoly in the intake manifold/tract. Many intake systems show some sort of "blip" at a certain rpm. You see it in all the M30 graphs that Todd has posted, sometimes with a shift in rpm one way or the other due to a worked head, etc.
The best comparison is my TT635 vs Todd's. That blip is in the identical spot even though the turbo system are completely different as well as the engine management.

Sweeney wrote:Rich, that dip is typical of M30 engines... assumed to be a resonance anomoly in the intake manifold/tract. Many intake systems show some sort of "blip" at a certain rpm. You see it in all the M30 graphs that Todd has posted, sometimes with a shift in rpm one way or the other due to a worked head, etc.
The best comparison is my TT635 vs Todd's. That blip is in the identical spot even though the turbo system are completely different as well as the engine management.

Thanks for the explanation for the cause of the dip. I wonder if the older L-jet intake manifolds used on the E12 would have the same dip. Don't know if it would be worth the hassle, but IMO, the L-Jet intake manifolds sure look nicer than the later Motronic version.

Rich

Skeen wrote:How much boost was the e23 running? The shape of the curves are all pretty similar (on that graph), it just doesn't reach the same numbers. The horsepower certainly keeps climbing high though.

I think I need a 1 bar spring now...

e23 had 15psi.

Todd

thank you standalone and stellar tuning!

gol10dr1 wrote:thank you standalone and stellar tuning!

Thats what I was going to say, the biggest deal there is the gain from tuning with the SEM MS vs Motronic. Its huge, especially with in the low end area.

In defense of the Motronic, if you tune it as much as Todd has done with the MS, the difference would not be as great!

RussC

Rich Euro M5 wrote: Thanks for the explanation for the cause of the dip. I wonder if the older L-jet intake manifolds used on the E12 would have the same dip. Don't know if it would be worth the hassle, but IMO, the L-Jet intake manifolds sure look nicer than the later Motronic version.
Rich

Hopefully I'll be able to answer that question when/if I go turbo.

Todd: I'm now a believer in your turbo. 250 lb-ft of torque at 2.5k and 350 at 3k. That's INSANE!