3.6 upgrade to 350 HP?
12-29-2010, 05:11 PM
#16
Rennlist Member
It is my understanding, when you change the cam profiles, you should also change the springs and retainers to match the new cams; which springs to use I can not tell you, that is far beyond my knowledge.
12-29-2010, 07:16 PM
#17
Nordschleife Master
We're all different in what floats our 964 boat when it comes to wheels, as can be seen here (you'll need a coffee or beer to enjoy them all
):https://rennlist.com/forums/964-foru...owed-idea.html
12-29-2010, 07:20 PM
#18
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Join Date: Dec 2010
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The headers/exhaust and cams are good mods to allow better breathing, the 964 heads in standard guise are good enough for 350HP so unless a real idiot has been working on them these won't be the bottleneck towards 350HP.
I can think of two or three things that will:
1) fueling/injector size: you don't mention bigger injectors being fitted, standard items flow just about enough for 295-300HP.
2) flapper type air metering device posing a too large inlet restriction for achieving 350HP
3) valve springs: have these been changed to safely allow the cams to operate in the higher rev range?
9M achieves 325-330HP with standard engine internals, a cat bypass / cup pipe, and a restriction free MAP inlet metering device.......and of course perfect fueling (large injectors) and ignition through their Motec package.
Adding cams, porting and headers should bring 350HP within realistic reach...
I can think of two or three things that will:
1) fueling/injector size: you don't mention bigger injectors being fitted, standard items flow just about enough for 295-300HP.
2) flapper type air metering device posing a too large inlet restriction for achieving 350HP
3) valve springs: have these been changed to safely allow the cams to operate in the higher rev range?
9M achieves 325-330HP with standard engine internals, a cat bypass / cup pipe, and a restriction free MAP inlet metering device.......and of course perfect fueling (large injectors) and ignition through their Motec package.
Adding cams, porting and headers should bring 350HP within realistic reach...
Thanks!
12-29-2010, 10:23 PM
#19
Rennlist Member
Freedog, your avatar says Pacific Northwest, I would contact Steve Weiner in Portland CLICK HERE , no affiliation... he will be able to help you with any performance upgrade to your car; comes highly recommended.
12-30-2010, 09:07 AM
#20
Performance valve spring kits with titanium retainers can be safely used up to 8000RPM without valve bounce/float. Pictures can be found here:
http://drcamshafts.com/ click porsche cams --> 964 valve springs
http://www.fvd.de/us/en/Porsche-0/96...s-911-964.html
A lower valve cover is removed easily enough to check what you have. Until then I would impose a 7000rpm redline.
The question on injectors en ECU's has many potential answers. Fact is you need injectors with a minimum size of around 235 cc/min to fuel 350Bhp (standard is 192cc/min).
Geoffrey has flow tested the standard barn door type air metering unit, the results of which suggest it is restrictive with 350HP worth of airflow. This already points you somewhat in the direction of Ecu choices.
Two main options are:
1) Standard Motronic adapted to run with 993 style hot film MAF and custom mapping to suit your choice of bigger injectors and existing cams/headers.
2) Aftermarket programmable ECU with MAP sensor air metering.
I would personally make a decision based on availability of local rolling road tuning expertise, and your tuners preferences AND/OR supplier support from a distance (base maps, trouble shooting etc.)
9M/Geoffrey supply plug and play Motec kits (this saves a lot of hassle making custom harnesses associated with other aftermarket Ecu packages). Aftermarket programmable Ecu's offer future versatility should you decide at some point to switch to throttle bodies etc.
Vitesse racing offers piggy back MAF kits to work with your existing Motronic which is quite easily adjusted to larger injectors than standard. FVD and Cartronic also do MAF kits without a piggy back, these would require emulation software to read and alter the chip during live dyno mapping.
Steve Weiner has also been suggested as a good source for a fitting solution.
I'd talk to as much of these companies as possible to check for their recommendations, support schemes and associated pricing....
Hope this helps
