Woodster

WELL GUYS AS MOST OF YOU KNOW, OVER THE WINTER
I MODIFIED MY CAR TO RENNLIST STANDARDS: PROTOMOTIVE ECU,
KEVIN'S STAGE 2'S, ETC. MY BUDDY HAS A 99 ACR VIPER (RARE,
ABOUT 470 FACTORY HORSEPOWER. 50 DEGREES. SUNNY MORNING
(FORMULA ONE RACE IN PROGRESS), FROM A ROLL 3 TIMES: RESULTS
ACR VIPER COULD PULL ONE TO TWO CAR LENTHS EVERY TIME. WE
RAN SIDE BY SIDE FROM 30-40 MPH UP TO 140-165 EVERY TIME. TO
SAY I WAS SURPRISED, PERTURBED AND DISAPPOINTED WOULD BE
AN UNDERSTATEMENT. I SPENT UPWARDS OF $15K ON MOTOR MODS
THIS WINTER!!!! OH I WAS RUNNING ON 3/4 TANK OF GAS, ALL 93
OCTANE (ETHANOL BLEND), @ SUPPOSEDLY 1.O BAR OF BOOST. CAR
SEEMS TO RUN, IDLE, DRIVE SMOOTHLY, BUT I THINK IT SHOULD BE
FASTER! THIS IS A STOCK ACR VIPER, BUT I AM IN THE LAND OF
TOMMY ARCHER (AND SOME MODIFIED STEET VIPERS). ANY SUGGESTIONS,
I AM PISSED! ??????????????????

TB993tt

"Modified to Rennlist standards" - says who
Until Todd K spends the time and $$ fine tuning the ECU on his engine dyno to your exact engine spec mapped for specific boost levels you just have some bolt ons and probably about 440hp unless your boltons are really mismatched in which case you may have less than stock
Can other Rennlisters with these bolt-ons prove me wrong - any 60-130 vids out there

hatchy

Have you had your car dynoed to make sure the mods you made are making the power you expect? 1-2 car lengths @ 140+ MPH doesn't seem that bad...

Woodster

no dyno sessions so far, I am not even sure who can do this in Minnesota??. Imagineauto may
be my closest??? The guys from my shop that did the work are at the porsche club race in
Atlanta this weekend but they do not have a 4wd dyno. I may have to talk to Stephen @ Imagine
Auto.

ScottMellor

Make sure you get on the right kind of dyno or disconnect the front drive train. The viscous coupler is expensive. Ask me how I know......

tlark

Kasper has a 4wd dyno.

I wouldn't even attempt to tell you what may be wrong if anything w/your car. I will tell you the ACR is a good car and w/minor mods can run easy @ near 500hp with torque #'s too match and/or his gearing. The real measure of the car shouldn't be running a stright line anyway IMO. I'm w/hatchy, 1-2 car lengths isn't bad and as you explained it he was pulling you out of the hole "30-40mph" which suggests his ratio is more suited for a N/A car unlike our turbos.

Woodster

TB, what i meant was I did what seemed to be a fairly common (and hopefully), sensible
approach to modifying my 993 twin turbo. I do not have access to the guru tuners that
some of the east and west coast folks do. I want the car very drivable and i want power
over a broad range rather than peak high horsepower and no torque down low. In that
sense, I may have achieved this as it starts, runs and drives, and accerates (seat of pants) very well. Maybe my expec-
tations were too high and this acr viper is too much?? I would like opinions of my next step
which may be finding 4wd dyno and seeing where I am at. I am praying that motec is not
the only answer(another $10k--ouch) any thoughts?

Kevin

Topend engine rebuild which includes camshafts, flame rings, Carrillo rods, injectors and so forth.. And custom tuning, Gunter is coming this month.. If you set you sights on having to beat the Viper, it it's going to be at great costs.. $$$

hatchy

Have you consider the unholy option: Nitrous? If you just need a little more power, this may be a cheap way to get it, and reclaim the 1-2 car lengths.

Rob 97 993c2

why is it so hard to beat a 470hp stock vipor?

Woodster

The Vipers are quite fierce if you happen to run across one (especially the 99, and the 2004/2005
new body style). what we are up against is 400 ft./lbs of torque at 2000rpm! (and on the acr
peaking at 460-495 ft./lbs!!!, combined with gearing, as someone else mentioned and you have
a combo that is very hard to stay with!

Kevin

You can't run NOS in an air-cooled turbocharged engine.. Unless you want to drop every valve and seat into your pistons... And that's after you have replaced every piston from that last go around.. I've done it and lost $$$.. Piston and liners get expensive, and I can rebuild the engine myself..

Jean

Marty I am with TB and Kevin on this one, you need serious $$$.Todd is great but he is not very familiar with Kevin's turbos so unless he has tuned your engine with the turbos and exhaust etc.. on his dyno, there is not much he can do.

If Stephen is not too far from you, your best bet is to ship your car to him. He is very familiar with the turbos and can remap properly an ECU to match the other components to have a well rounded engine. You will feel the difference for sure.

Kevin

Jean, Todd tuned Seege's car, same spec.. Stage 2's Z/C.. The next step is a engine build with camshafts, valves, porting and so on.. Major $$$ are involved.. It would be a similar build that you have just done, and most of it is done not to make power, but to make the engine live with the added power from injectors head work (valves) and camshafts..

Jean

Oh! then he has the right maps as CJ took his car to him for dyno tuning I believe. I heard it is very fast!