DivineE

I've just looked and cant see anywhere a thread that collectively brings together peoples dyno results. There's a site here in the UK but there are only a limited number of cars on it. I think a GRAND collection of results for modified 944 turbo's would prove a real asset for people trying to establish which modifications produce which results.

I suggest a standard format e.g.

-Graph pic-

Specs:

Block/Capacity: 9xx 3.2ltr (108mm bore)
Head: 2.7 ported and polished
Cams: Stock
Turbo: Turbo Dynamics
Engine Management: 9xx chips, Vitesse Maf and piggyback
Boost controller: Manual
Ignition: Stock
Injectors: 850cc (85lb/hr)
Wastegate: Tial 46mm
Intake: Stock
Exhaust: 3" custom, no cat, standard manifold
Intercooler: 9xx stage 3
DV Valve: Turbo dynamics

V2Rocket

108mm? jesus

RolexNJ

Ben, this is the best thread that we have in the community. If you ever get your results and want to be added to it, let us know. Take a look at this one.

https://rennlist.com/forums/944-turb...-10-hp-tq.html

CarbonRevo

108mm bore? Why so big? IIRC, the 3.4L 968 Turbo down south has like 106.5mm bore.

alxdgr8

I believe 108 is what everyone uses for 3.2L builds.

DivineE

I don't think that can be correct. 108mm bore with the 3.0 crank gives 3246cc or maybe its 3248cc something like that anyway. With the 3.0 crank the rods come SERIOUSLY close to touching everything at that stroke, I don't think you could get 3.4ltr with 106.5mm bore without the rods connecting with the block and or bottoms of liners? Maybe I'm wrong and it is possible but it didn't look it with the setup we used.

Thanks Rolex for the nudge to the other thread. I did try a search first. I was hoping with this thread to look more closely at the characteristics different mods give. For example a 400hp 2.5 motor running a big turbo and bigger boost seems to have a very linear graph where it rises constantly to the redline. However most of the big bore engines I've seen peak early and drop off at the top end. I'd like to see if we can corrolate the data against mods to establish why and what parts affect the curve?

marcoturbo

A bit OT: you run 9xx chips with a Vitesse MAF and PB, not the VR chip/board ?

Thom

Difficult to compare PW/TQ figures without a benchmark - US cars usually show higher values than EU cars and aren't measured on the same dyno.

If I'm not mistaken the figures on the UK league page were observed on the same dyno.

DivineE

I'm rusty on the details as it was a while ago but the base ecu chip (passenger footwell one) is from John as he likes how flexible it seems to be to correct for other mods etc. Then the input signals are altered by the piggy back unit Vitesse provide to fine tune and fool it into thinking and a standard air mass meter etc. Seemed to work pretty well.

As for comments on comparative dyno's and their differences. I'm less interested in the figures, more interested in the shape of the curve and who's managed to a. get the fueling right and b. flatten out the power curve give or take 50hp or ft/lb it doesn't really matter.

fast951

A great idea for a thread, will help everyone decide on what is needed to get a certain power band.

If you are using the Vitesse MAF, you must be using the chip/board. The PiggyBack is there for fine tuning. The Vitesse software supplied on the chip/board is True MAF software, no need to convert it. Best to check to make sure this is the case. A simple test is to pull the PiggyBack out and replace it with the shorting plug, your car should be drivable as the chip/board by itself gets you anywhere from 95-98% on target.

BTW. I think the 108mm bore is great. Do you have a dyno chart?

DivineE

Maybe your right? But thats not how I understood it. Do you supply both chips for the car or just 1? Maybe John supplied the other? I unfortunately don't have a dyno chart for the car but like many other big capacity cars it suffered heavily with dropping off at the top end even with a very large turbo, Maf, good wastegate and fairly free flowing exhaust. Some people (RolexNJ seems to be the best from the graphs I've seen) seem to be able to keep the torque flat to (or near to) the red line. I'm wondering why and also what mods improve the low end (other than capacity) for those boys with the opposite graphs?

DivineE

[QUOTE=fast951;7094254]

If you are using the Vitesse MAF, you must be using the chip/board. The PiggyBack is there for fine tuning.
[QUOTE]

Could you remind me the layout of the engine management system / how it fits together and I'll try and remember exactly what was done? i.e. KLR etc. What do they all do? Where is the factory boost cut, where are the fuel, throttle maps stored? etc

fast951

MAF in the engine bay. Chip/board inside the DME. KLR remains as is we don't touch it. PiggyBack gets wired by the DME connector.
Fuel and ignition maps are on the chip/board inside the DME. Unless you have the V-FLEX upgrade, there is no overboost cut.

DivineE

Thanks for trying I'm afraid my memory is a lost cause on this. I remember your MAF caused a WORLD of trouble before we finally discovered you cant put a MAF sensor in direct line of sight of the turbo (because the turbo creates a vortex of turbulance that confuses the sensor!) then once we put a 90 degree bend between them it worked a TREAT Jon said your mapping was almost spot on even for a 3.2! Maybe it was all your chips in the end? My car DEFINATELY had the factory boost cut originally. Kicked in after 2secs or more of constant overboost and cut the fuel. Not subtle and triggered it many times when experimenting in ignorance with boost encancer on my otherwise standard car.

One thing I know for certain is that in the end the whole wiring loom had to be replaced because chips wouldn't fit on the '85 board. It was a different number of pins being an early model.

p.s. I don't see any responses people.. where are the big guns hiding? Are there any quick cars out there still running?

Thom

Interesting...
As your car has a 9XX-built 3.2 I assume the turbo is a custom dual ball-bearing unit built by SPS?

My SPS turbo is a monster (saw 16psi at 2800rpm in 4th gear yesterday evening) but I'm still running the airbox with a modified original J-boot, which means a 90° - if not more - bend before the turbo.

Will be fitting a straight pipe to the turbo in the coming weeks, curious to see if I go through the same issue with the MAF.