Dyno Run

[Guest]

After having the Guru 1a kit fitted and a Bailey DV I've got the car booked in for a power run next Wednesday morning.
This is all totally new to me so what should I be looking for and If I adjust the Accuboost during the run what should the optimum settings be?
I need to be able to ask the right questions and tell the guy doing the test what I want without sounding like a total goit so any suggestions would be much appreciated.

Incedentaly it's only costing £20.00 (possibly a bit extra if I ask them to start tweaking) it's in North Lincolnshire if anyone else is interested I have the details.

Cheers, Tim.

 

[Diver944]

What you really need is an accurate means of measuring the boost. The Guru chips are designed to run at 15psi of boost (1.05bar). The in-dash gauge only goes up to 1 bar of boost so if your accuboost is turned to 1.2 bar you won't know, plus it is a little slow to react so if it starts losing boost at high RPM the gauge tends to sit there at 1 bar. Hopefully the dyno place can plug in their own gauge so it won't be a problem.

I'll stick my neck out [] and guess that if your WG is still unshimmed you will see a rapid rise in torque and power but then a sudden drop in torque around 4000 rpm as the exhaust gases force open the WG. This is my chart with an unshimmed WG and a Guru kit

 

[John Sims]

Make sure all your fluids are topped up and you don't have any leaks. You will be stunned how vicious the test sounds and convinced that they are thrashing your car to within an inch of it's life.

The main reason for the test would be to set the Accuboost to allow the maximum boost without the fuel air mix going lean. The Guru chips are set to work at about 16 PSI but you may get away with a bit more if (as in Paul's case) the engine is seen to be running a little rich at that setting.

Also note that, subject to callibration 300 bhp on one dyno may not equate to 300 bhp on another. I have always considered dyno sessions as a tool to check how the car runs under load and to acheive an improvement from when it arrived not as a "set in stone" demonstration of how powerfull the car is. The other thing to note is that a dyno measures the power at the rear wheels where as all performance mags relate the power at the fly wheel. To claculate the power at the flywheel from the power at the wheels is a little open to debate and hinges on the percentage of power lost or absorbed by the transmission. The power loss will be different for every car and therefor the power reading (at the engine) will be approximate.

 

[John Sims]

Incedentaly it's only costing £20.00

This is very, very cheap. I've never paid less than £100

 

[Diver944]

I just had a simple power test run that cost £35. There was no tweaking just three runs and the measurement.

It might be a good idea to have a full tank of fuel and some weight in the back. My car kept spinning its wheels so in the end they had to get two blokes to sit in the boot with the hatchback up []

I couldn't look, there is my car doing 170mph a few feet away from me with two fatties sitting in it [][]

Oh, and make sure your tyres are at the right pressure and the car is fully warmed up before you get there to save time for them to warm it properly.

 

[Guest]

Thanks for the tips
The place is a recommendation so I'm confident that they know what they are doing.
I'ts about 30 miles away from me so the car will be well warmed up

I really must sort out a proper boost guage!

Tim.

 

[hartge bob]

Actually last time I was at the rollers me and a mate both thought it would be a good idea to warm our motors up before the run. The operator told us this was not necessary as by the time they've plugged everything in and are ready to run it will be warm enough.

To prove his point my mates car was run twice, once while pre warmed and once at the end of the day when cool (it was a peugeot club shootout). It made an extra 12bhp when cooler, same rollers, same day!

The first run with the engine warmed up got the alloy inlet manifold so hot the operator was spraying cold water on it to cool down the induction temps a bit.

Rob

 

[Guest]

ORIGINAL: Diver944

I just had a simple power test run that cost £35. There was no tweaking just three runs and the measurement.

It might be a good idea to have a full tank of fuel and some weight in the back. My car kept spinning its wheels so in the end they had to get two blokes to sit in the boot with the hatchback up []

I couldn't look, there is my car doing 170mph a few feet away from me with two fatties sitting in it [][]

Oh, and make sure your tyres are at the right pressure and the car is fully warmed up before you get there to save time for them to warm it properly.

THere no way they would have done the run in 5th gear, 4 at most prob 3rd!!! So it would have been about 100mph...

Still you done want the rollers to lock at that speed eh!!! []

 

[hartge bob]

My old Hartge 535 sport was run in 4th up to nearly 130mph!

They even checked the speedo calibration up to 100mph (which was surprisingly accurate too given the fitment of 18" rims as opposed to the standard 16")

As Paul says, standing three feet from the car when it's doing this sort of speed, scary and the noise is incredible, felt sure it was going to blow, looked in at the rev counter and it was only doing 4000rpm, still another 2300rpm to go [:-].

They don't let you in the dyno room at that particular road anymore, due to health and safety should anything break during a run. I don't think I'd want to go back in their anyway (at least not with my car [])

 

[Fen]

Bob Watson ran mine in 4th. He said he tried 3rd as his preference but just couldn't stop the wheels spinning.

 

[Guest]

ORIGINAL: Fen

Bob Watson ran mine in 4th. He said he tried 3rd as his preference but just couldn't stop the wheels spinning.

Show off!! []

I hate watching the car on the dyno, its frightning, but really is not much different from driving along the road at 100mph, it just seems soo unnatural..

BTW if you think that your car is bad on the dyno, i have a few video clips of 1000bhp skylines 4wd and they are SCARY, very SCARY.

 

[Guest]

ORIGINAL: Diver944


I'll stick my neck out [] and guess that if your WG is still unshimmed you will see a rapid rise in torque and power but then a sudden drop in torque around 4000 rpm as the exhaust gases force open the WG. This is my chart with an unshimmed WG and a Guru kit

Exactly right , need to get those shims fitted!!

The Dyno only went to 250 but the operator conservativley estimated 275 to 280 BHP and 310 to 320 lbft's torque.

I've been living with the modded car for about 10 days now and it's fantastic, I just can't get enough of the smooth power delivery in fourth and fith gear.
Well worth the money spent which to be honest was a bit of a bargain.

Tim.

 

[Diver944]

Woohoo! 250 seems a low limit for a rolling road, what are they used to? Robin Reliants. A 55bhp rise for under £250 is a bloody good upgrade isn't it? [] Turbo cars are marvelous [8D]

Leave the shims off for a bit longer, then when you do put them on the extra oomph at high revs will seem even better

 

[944Turbo]

I have my boost set to 16.5 PSI (dropping to 15) pretty sure it will go higher safely (waiting to see if Slim blows his head gasket[]) as I think I am still running too rich, but I will wait for a rolling road session before turning it up any higher. Will be nice to get another power gain though, especially as the power seems to tail of a bit in the summer.
Tony

 

[Fen]

Speaking of head gaskets, I ordered a Cometic yesterday for £65+VAT, and a set of Raceware studs for somewhat more [8D]

I do NOT want any leaks...

 

[Diver944]

Well myself and another local Turbo owner are booked into Jamsport in Northampton for a dyno test on Thursday 15th April. Now that I have sorted out my weak wastegate and am running at 16 psi I hope to be comfortably over 300bhp and nearly at 350 lbft torque (compared with 287 and 331 last time).

Where did you get the cometic head gasket from? []

 

[Fen]

Cometic []

Actually the guy said they normally only supply the trade but becaue I picked up his card at Autosport that was acceptable - they deal direct at shows if the public are able to attend. I posted his details in this thread: http://www.porscheclubgbforum.com/tm.asp?m=43161

 

[937carrera]

I have recently fitted a cometic MLS gasket to my 951 race car.

Make sure you compare the holes for the water flow with your original gasket........the Cometic gasket is NOT an exact copy of the current Victor Reinz gasket. I have already spoken to the US about this and am in contact with the UK MD.

Here's a piccy, MLS at the bottom, look at number 4 cylinder

 

[Diver944]

Thanks for the post David, I wondered where Chris Heeleys car had gone, and was interested to read in your website that it was built from an original Silver Rose car. The Silver Rose owners are always eager to hear how many of their cars are left now. Does the new paint job mean it's now an Orange Rose????

Good luck in the Open, it'll be nice to see a few more 944 Turbos back on the track

 

[Fen]

That's interesting - I haven't compared it to another as the HG that came off the engine (a widefire) was binned long ago, and loads of guys on Rennlist seem to be running the Cometic. Thanks for pointing it out (I think - it is something else to worry about though).

If I uderstand correctly then you are running it, or did you decide not to fit it after you spotted the difference in waterway openings? What have Cometic said about it?

BTW I hadn't followed the link in your sig before. The orange car looks very nice. How did the race go yesterday?