Impressive Fly911

[QUOTE=sp_cs;9262236]No offence intended as i know little about not very much, but is that dyno plot accurate? That's showing 30-40 bhp/torque gains with your upgrade package? Care to detail the changes?



sp_cs....no worries.........I had posted a composite to make it easier to see before/after, but here are the actual dyno runs, and description as originally posted by the Dzug guys.....

"""Thats a whopping 24hp and 30(!)lb/ft gain over the stock CIS for an identical motor, SSIs and megaphones.

The car has been transformed, pulls crisply and SOUNDS amazing with the ITBs.

There are still gains to be had with tweaking the timing, and we could probably get more out of her still if we had coil packs, but not bad """

http://forums.pelicanparts.com/uploa...1472661335.jpg
http://forums.pelicanparts.com/uploa...1472661360.jpg

here's a link to the original post

http://forums.pelicanparts.com/porsche-911-technical-forum/741911-d-zug-tours-rsr-dyno.html

and dyno pull vid

https://www.youtube.com/watch?v=QdXp67tdbbE
https://www.youtube.com/watch?v=xaj0FyEmc68
https://www.youtube.com/watch?v=hIehm1WuxPI&feature=youtu.be

Incredibly helpful, thank you!

I've got a fresh stock SC (small port) build that I'm getting running on carbs, but I think will be ITB in the future. Tried it once before in the 90's with a TEC3 ECU and TWM but never got it running well.

Looks like the juice was worth the squeeze. Could probably go even better with a bit more cam. Regardless, I like it.

Currently waiting for the MFI machine work to be completed for the 2.8 I'm building.....the good guys are always backed up.

Most ECU's suck at getting ITB's to run perfectly on the street. Because a) they have only speed density tuning strategy available (which is useless with ITB's), b) they have only Alpha-N mode available (also useless on anything but a race car).

Key to getting ITB engine running perfectly is to have at least MAP compensation table+MAT compensation table on top of Alpha-N or the best method is to have MAP/Alpha-N hybrid load.

hybrid SD/AN modes exist in many software systems. However, to get them to work requires some knowledge and experimentation to overcome the issues changing from one mode to another smoothly.

Also, It is not so difficult you get ITBs to run well with SD algorithms provided you understand the scaling required to match the non-linear MAP signal versus load. I do this often with very nice results.

As they say... "give the engine what it wants".

There are many solutions to the ECU and tuning component of these installations just as there are hardware and intake solutions. One size does not fit all.

Using a Resonance Plenum over ITB's results in a 25-45 lbs-ft torque boost from 2K to about 5500 RPM, all things being equal.

The effect is quite noticeable and works on all 911 engines. :) :)

Naturally, the plenum must be sized (matched) to the displacement.

what plenum is the choice for 3.2?

24-45lbs... thats a lot!

has anyone done back to back test with the a 964 plastic mani ITB 3.2 dyno to see were the gains are?

i would assume its helps a lot for low rpm running issues with the ITBs.

i have a 3.2 twin plug, 964 cams now and plastic 964 mani sitting on the self.

What engine management are you going to use with that 964 manifold. And it is not a direct fit. Are you going to use it with itbs?


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Agree, though tuning by pure SD with the effective available MAP range of 70-100 kpa is not going to make a perfectly running car. And if you have wilder cams then range will be even less. Problem is that you will have many overlapping VE table areas, even though you may divide VE table MAP cells in 2-3 digit inceremtns at higher rpms. Transient response at low rpms/loads (= city driving) will be compromised.

BTW, I always give engine what it wants ;)

Very cool information from all.

Depends on cams and compression ratio,...:)

Liking the plenum - bespoke or off a shelf?

I've bought 993 intake halves as a starting point. Sending to William Knight for his t-piece filter arrangement to be made up.

MegaSquirt has an "ITB mode" that blends Alpha-N and Speed Density.

I'm going to try that 1st and experiment. If it doesn't work out, I'll try jpnovaks tried and true method. :)

I was thinking of doing the mod in increments since the motor runs well. I would first try adapt the plastic manifold with custom short intake blocks in which I recall a few people sell already. You can trigger the resonance with a aftermarket adjustable shift light. I'm not sure you can get away by just re-chip the motronic?

Next phase would be a stand alone followed by ITB's. No know itb's aren't worth the $ if you aren't spinning above towards 8k but the look and sound fantastic.

Al ikosmals dyno plot contradicts that somewhat?

no i dont thinks so but thats just my opinion. i dont know much about that motor other that is a 3.2SS which should spin more freely than a 3.2. the dyno graphs indicated thats is a nice warmed up street motor peaking around 6100. i think Al builds nice motor with creativity given the realistic budget of normal folks like us. if he had an open wallet then all this would be easy.

basically once you replace the standard CIS( toilet plunger) with EFI you a eliminate significant restriction on the intake track. thats were most of the gains are along with more precise fuel metering. Be it itb carbs, efi with log manifold or itb efi, the peak gains will be similar its just that drivablity, torque curve and character may differ

itb tuning at low engine speeds are more difficult compared to a log type tuned manifold especially with hot cams which is why you kinda wanted itbs in the first place right? with these late type variable manifolds (that steve have posted) adapted to the top of itbs, you can improve running issues at low speed and thickin up low end torque curve.

Having manifold on top of ITB's does not change the tricky nature of tuning the ITB's at all.

It does open up the possibility of using a MAF sensor, though.