[Vedder]

Its the first dyno that ive done.
The car has a fully rebuilt engine with less than 8000 miles on it.
The mechanic reckons that the variocam solenoid (that rattles sometimes) is erratic and not working correctly.
Compression is very healty and no codes whatsoever on the DME.
Heres a list of the mods:

RS Barn Performance Head Stage 1
RS Barn Performance Cat Back
RS BARN Custom Performance Chip Stage 1
968 Engineering Airbox Modification w Trim Rings
K&N Air Filter
NGK Iridium Spark Plugs
ETC

Please helpme understanding why??

Partial Post: Please Login or Register to read the full post.

[Mark]

You are missing 1000 RPM at the top.
Assuming stage head=header and not actual head should you not have the Stage2 chip which is made for the header and cat?
What gear were the pulls in?
What does a stock 968 pull on this dyno?

Partial Post: Please Login or Register to read the full post.

[flash]

agreed on missing upper rpms - that test should have gone past 7k

agreed that with the header, it should have had the stage 2 chip - not sure why it has the stage 1

all that aside, with no "before" run, there is no way to tell if this is right nor not - all dynos read differently, and there are way too many variables that can result in huge differences in readings (gearbox temps, intake temps, intake sensor location, engine temp, yada yada)

don't get hung up on numbers - the only thing that is valuable in dyno readings is the before and after differential - numbers don't matter - it's the area under the curve that shows improvement that matters

Partial Post: Please Login or Register to read the full post.

[Johannvb]

Stage 1 Head = Stock, just reconditioned.

But with the mods you listed you should be somewhere in the region of 150kw on the rear wheels at 6500RPM. At 6000RPM you should be somewhere around 140Kw. Why you're not getting that is a tough question.

These are my guesses:
- Maybe the Dino's info on the 968 is incorrect?
- Maybe your Cat is clogged up?
- It could be that the cam timing is off...belts not installed correctly?

Partial Post: Please Login or Register to read the full post.

[Vedder]

Hi, thanx for the quick replies.
Just to clear some confusion the car has a rebuilt head by RSBARN with valve job, but no header.
Header and cat are stock + RSBARN CAT BACK.
this dyno pull was the best of 4 runs and on premium fuel.
do you think that the theory of the solenoid no activating sticks? it could explain why the numbers are low, maybe like an 944 s2...?

Partial Post: Please Login or Register to read the full post.

[flash]

thanks for the clarification

as to the solenoid, you would see some change due to lack of variocam, between 1500 and 5k where it operates, but it would have no effect above that

but again, comparing numbers to another car is flawed in concept - it cannot be done unless you test it on the same dyno on the same day, and while you are at it, take care to make sure you take the same measurements of the conditions, particularly the intake and transaxle temps, which can each make a 10hp change by themselves

Partial Post: Please Login or Register to read the full post.

[flash]

i was just looking at the charts again and noticed the drag - 33kw? 44hp? that's huge - 35hp or 26kw is the accepted norm - is there something else going on? how heavy were those wheels?

is the "norm" power curve from a book or something? i've never seen that before

factor in where the curve should go at peak (which would be a lot higher than 5900 where the test cut off), and factor in the extra 9hp from the corrected drag, and you would be about 22kw higher

that is without taking into consideration anything else

clearly there is something wrong with the procedure, but without a "before" run, it's impossible to tell

the bottom line is that we know for a fact that the other mods work, and work very well - there is way too much data out there on way too many cars to dispute that, regardless of what someone with an agenda might think or say - you don't have to worry about those - i saw the thread on the other site - both of the guys making negative comments are clearly confused - that's happens a lot over there though - don't read too much into it

if it was a US car, i would suggest a blink test - however, being ROW, you don't have that luxury, and will need to connect to a hammer to see if the variocam is working - however, as i said, while it may increase things between 1500 and 5000, this will not matter over 5k rpm - you also need to run it up to fuel cutout to see how much you really have - if it cut out at 5900, you have a bigger problem

go back and do another run first, and run it to fuel cutout - if it still seems low, or the car is running slow, then you can look into other things

just as a check, your compression figures on a new engine should be near 200 at 8 cycles

Partial Post: Please Login or Register to read the full post.

[Vedder]

Thanx Flash for looking into it a bit more, if somebody knows 968's that you.
i can do a blink test, i did a mod with the cluster and piggy back into the dme, so i do have "Engine Light".
Theres no error codes, all i get is 1-5.
Regarding the wheels, the car has 17" 993 sport classic wheels (original) with 225/45/17 front and 255/40/17 GoodYear F1 all around back. So quite standard
I dont understand why the dyno stops at 6000rpm, i can rev the engine up to 7000rpm with no prob in spirit driving.

Partial Post: Please Login or Register to read the full post.

[flash]

no worries - let's see if we can nail it down

1-5 tells me that your variocam solenoid is working - it should pop a 1135 or 1235 error code if it isn't - the variocam still might not be, but that is an entirely different issue

it's possible that the cams are not set right - any idea how they did that when they put on the head?

what were the compression readings and at how many cycles?

the rather severe upper end torque drop says something isn't right though

any A/F charts from that run?

as to the 5900 cut out, i have no idea why it did that - i would ask the guy running the dyno if he did that on purpose - if he did, you should be entitled to a free run to get numbers to fuel cutout, since there is a considerable amount of power beyond 5900

also ask him where the drag number came from - was it measured or entered? as a torque tube car, the drag numbers are less than a drive shaft car - that is a very high number

i am a bit confused on the wheels - if they are the 993 Cup wheels that were OEM on this car, then they aren't a factor - however, the Sport Classic wheels (if they are anything like the Sport Classic II) are heavy - that would make for a drag increase

Partial Post: Please Login or Register to read the full post.

[Vedder]

I bought a new solenoid since the one in the car is rattling sometimes,ill give it a try tomorow and run the weekend with it.
just to see how it feels, i assume that IF its the solenoid somehow i should feel more torque right away.
If nothing changes, it could be the tensioner. but how does the tensioner fails since its hydraulic?

Partial Post: Please Login or Register to read the full post.

[PorscheDude]

Have tried disconnecting the solenoid thats in there already.
If it is bad and you disconnect it, there should not be any change.

Just a thought before you swap it out.

Have you considered having it dyno'd somewhere else that has a dynojet or mustang?

Partial Post: Please Login or Register to read the full post.