Markert Motor Works Dyno Thread (many inside)

[The Dark Side of Will]

That might be a bit light for 6.5 psi, but that's exactly what I'd expect a 4 psi curve to look like.

Once again, the centrifugal develops boost proportional to the SQUARE of RPM, so if it develops 4-6 psi at redline, it's making straight up nothing at low RPM... probably costing power due to parasitic drag.

[JGood]

That's exactly what a centrifugal supercharger does.

That's what a constant displacement blower like a Roots, Eaton, Lysolm, Kenne Bell, AutoRotor or Whipple does.

Automotive product advertised to be better than reality? Say it isn't so...

Centrifugally supercharged cars can be VERY fast, but just like anything else, need more than 5 psi of boost to do so.

This is what I was talking about. VF540 (centrifugal) supercharged e92 M3. 4-4.5 PSI. There's a gradual, steady gain from idle to redline. 10hp gain at 3k, 20hp at 4k, 40hp at 5k, 60hp at 6k, 80hp at 7k, 120hp at 8k.






Also the case with every other properly running centrifugally supercharged BMW that I've ever seen, ever.

Including the ones posted in this thread...

Rotrex s52:

[nando]

looks solid to me. who wants a big hump of torque at 2500rpm only to have it fall flat on it's face at 5500?

[328ijunkie]

Retuned a shop 335i with new fancy inlets. Still stock turbos!

[The Dark Side of Will]

This is what I was talking about. VF540 (centrifugal) supercharged e92 M3. 4-4.5 PSI. There's a gradual, steady gain from idle to redline. 10hp gain at 3k, 20hp at 4k, 40hp at 5k, 60hp at 6k, 80hp at 7k, 120hp at 8k.

Since torque is what boost increases, we'll look at that instead.
30 ftlbs gain (240 -> 270) at 3000 RPM, 80 ftlbs ( 230 -> 310) at redline...

With peak N/A torque of about 260, 80 additional ftlbs is 5-6 psi of boost.
That means that 30 ftlbs is about 2 psi.

This is the expected behavior of a centrifugal. A positive displacement blower would produce the 80 ftlbs across the board. That's what I thought you meant when you said "even power up the powerband"

I guess my interpretation of "something wrong" is chipped ring lands. A boost leak isn't "something wrong"... it's just poor workmanship on the pre-installed parts.

[328ijunkie]

I guess my interpretation of "something wrong" is chipped ring lands. A boost leak isn't "something wrong"... it's just poor workmanship on the pre-installed parts.

Previous owner of the installed blower 'fabbed' a A/W core into the VF Stage1 intake plenum extremely poorly as it turns out. We'll be attempting to reseal it or ditch it and buy a real made to be intercooled plenum from VF or ESS next week and redyno from there.

[328ijunkie]

Added test pipes and retuned E90M from earlier... Progression:

[328ijunkie]

F10 535i with JB4/DP/Map6 tweaks.

[ForcedFirebird]

Got TQ?

[nando]

yeah, for like 1500 rpm, then it runs out of breath. :|

[The Dark Side of Will]

500 ftlbs on the stock turbos in the 335 isn't bad either

[328ijunkie]

Forgot to post this from a while back. Earlier dyno tune on pump gas vs running full E85 here.

[328ijunkie]

Late August
Finally finished up a S54 E36 swap tuning. Epic Headers, 3" exhaust, CSL airbox, Magnaflow race cat, first run is before tune with no cat, second is adding cat with base tune, third is revising tune on dyno


E60 535i with 160k on it! First line was JB4 only map 5, second line is FBO (intercooler, DCIs, Downpipes) and our tuned Flash, little bit of E85 too.

[2mAn]

Dave, I know this is kinda OT but do you think the N55 is better than the N54? I believe you've tuned both quite a bit and Ive always believed the N55 was the better of the two, but I have zero experience

[328ijunkie]

Depends on how you look at to be honest. N55s are currently claimed to not have as severe fueling issues at higher power levels but then again no one is at the power levels the N54 guys are for the most part. I will say in many respects they are much more reliable but ultimately (as of today) N54>N55 if you want some real power, easily, and cost effectively. No one has extensively mapped the N55 ecu as this was the ECU that started the changeover that theyre now using in all the F cars and thus youre extremely limited tuning wise. Cobb has stuff for early N55 cars but only have defined a select few tables and have left as far as future support goes.