Griff Growl 2014 Rolling Road Videos & Charts

[macdeb]

spitfire4v8 said:

QBee said:

I have seen the Phazedmobile make 357 bhp on a proper rolling road, one we all trust.
My own car read 300 bhp on that same RR, and i was not a little disappointed. I expected around 330.
I am not 100% convinced about portable rolling roads.
They stick a lightweight rear wheel drive car's arse up in the air and expect to get accurate readings.
The first RR I took my car on was flat, and 3 of us had to sit on the boot to get proper readings.

there's nothing wrong with dyno dynamics dynos .. one of the most highly regarded dynos out there in fact.
what was the "trusted" dyno ?

[QBee]

macdeb said:

spitfire4v8 said:

QBee said:

I have seen the Phazedmobile make 357 bhp on a proper rolling road, one we all trust.
My own car read 300 bhp on that same RR, and i was not a little disappointed. I expected around 330.
I am not 100% convinced about portable rolling roads.
They stick a lightweight rear wheel drive car's arse up in the air and expect to get accurate readings.
The first RR I took my car on was flat, and 3 of us had to sit on the boot to get proper readings.

there's nothing wrong with dyno dynamics dynos .. one of the most highly regarded dynos out there in fact.
what was the "trusted" dyno ?

It was the dyno at Surrey Rolling Road. Dyno Dynamics. Fully installed version. Three of us met to have a dyno session last year. All three cars' readings came out where we would expect, Peter's at 357 bhp (cannot remember the torque), mine at 300 bhp/330 torques, Graham's (TV8) 5.3 at similar numbers to mine because his runs had to be stopped at 4500 rpm due to incorrect fuelling high up. His car has since made much better numbers, in line with the engine's spec.

I don't have an issue with Dyno Dynamics dynos, far from it. My issue is with how some are operated, with particular reference to ensuring that there is as near perfect as possible a transfer of power from tyres to rollers.

I was watching the cars being tested at the griff growl. The guys worked hard and did a good job, but there were a lot of problems with grip on the rollers, giving some very strange results, such as mid-300 torques for a 6.2 LS Griff that had previously been measured at 500. I saw several cars nearly out of the rollers, and the tie down straps kept having to be tightened. There was no weight applied to the rear of the TVRs, which I would hazard (and someone else pointed out to me as well) did not help with the overall grip of what is a powerful but light car. The 1971 (I think it was) V8 Aston DBS managed about 285 bhp, on what must have been a fairly well worn engine, but it was a much heavier car than a TVR so made better traction on the rollers. IMHO the arse-up position on the mobile roller set up didn't help the TVRs a lot, as the weight balance of the car was further forward than usual. But I am not an engineer, my Physics knowledge stopped at A level.

I myself have had trouble with wheel slip on a dyno (it was a different concreted-in Dyno Dynamics set up) as I said above, even with my puny 300 bhp. I=On that occasion three of us had to sit on the boot lid to get correct readings.

I suspect that if more attention had been given to better tying down of the cars at the griff growl, and perhaps some serious weight in or on the boot, we would have got more reliable results. I am far from the only person doubting the results on Saturday.

[FlipFlopGriff]

CHIMV8 said:

It does seem a common theme from the Growl RR

The rolling road was calibrated about a week before so maybe just atmospherics - it was warm
FFG

[MPoxon]

Don't forget to add your figures to the Wiki, poor show so far...

http://www.pistonheads.com/GASSING/topic.asp?h=0&a...

If you are worried about breaking the table or cannot be bothered to edit it then post in this thread the following details and I will add it for you.

• Model
• Modifications
• BHP
• Torque

[pjac67]

I can't upload images for some reason (no issues before ?)

Message looks OK ie jpeg file not too big:

"Image Successfully Uploaded and the tags have been added to the form below. Please close this box to return to your post. "

Any pointers?

[Quinny]

Well I've just got back from getting the car checked out, and as I suspected there are absolutely no error codes, sensor issues or lambda problems

Just for Daz though....one issue that did come up was how far out my tacho is..... I told Daz that at 100 mph it's doing 3250 rpm

In fact it's closer to 2750 rpm...

[MPoxon]

pjac67 said:

I can't upload images for some reason (no issues before ?)

Message looks OK ie jpeg file not too big:

"Image Successfully Uploaded and the tags have been added to the form below. Please close this box to return to your post. "

Any pointers?

Hi Paul, thank you very much for taking me out for a spin at the Growl, wow what a fantastic machine!

I have no idea why the upload is not working. You could try uploading to somewhere like photo box and posting them that way, if not do you want to email me those graphs and I'll try posting them up?

[grngriff]

Hi mpoxon

Could you post up my results on the wiki pls
Can't seem to do it off a iPad
Grngriff
4.3
Upgraded to BV with chip,decatted,carbon trumpets,smooth bore etc
Bhp 287.4
Torque 310

Many thanks
Pete

[MPoxon]

grngriff said:

Hi mpoxon

Could you post up my results on the wiki pls
Can't seem to do it off a iPad
Grngriff
4.3
Upgraded to BV with chip,decatted,carbon trumpets,smooth bore etc
Bhp 287.4
Torque 310

Many thanks
Pete

Hi Pete, all done for you, thanks for posting. You must be pleased with those figures, they are better than most Griff 500s

[grngriff]

Hi MP oxon

More than happy with the results, I'm glad I took it to the original engine builder for the BV upgrade TVR Power, as the results speak volumes about his knowledge.
It might be a little higher if every one else's results were down on the day.
Maybe a decent ecu now might be on the cards just to make it spot on!

Regards

Pete

[MPoxon]

That is certainly impressive for a 4.3 you are only 3BHP off of my 500 which was 309BHP on TVR Power's dyno 2 weeks prior so you may well have a +300BHP Precat!

Dom certainly does know his stuff. If you are looking at mapping then have a chat with Mark Adams or if you want a whole new ECU then Dom's MBE offering is very good, sounds expensive at first but when you consider the price is fully fitted and mapped with a new loom it is quite reasonable. However if you are getting those figures there cannot be much wrong with the existing ECU or mapping so maybe just spend the money on fuel instead

[stevesprint]

As Surrey Rolling Road appears to be over reading here's my SRR graph to support your argument. You can see I had 269 bhp at SSR last Oct with my standard and well-seasoned 4.3. This is 9 bhp more than my 2013 Growl reading of 260bhp in red on the second graph.





For the 2014 Growl run (in blue) I've improved my top end AFR by extending to fuel table to 6,200 rpm. This gave me an extra 3.8 bhp compared to the Growl last year and is still 5 bhp less than SRR without the improved AFR. Therefore my big question now is if I revisit SRR will I see 269+3.8bhp?

The AFR dip in blue at 3,200 was deliberate as all the old tuning books recommend 12.5 AFR for max torque and 13 for max power. I've since been re-educated by Jools to have a straight AFR line starting with 13.3 at 2,000 going down to 12.7 at 6,000 rpm.

It would rude if I didn't take this opportunity to thank our overseas 14CUX boffins for helping us understand the internals of the 14CUX. I'm still in shock they have reverse engineered the ECU and shown us everything from the basics like changing the warm up fueling to the most impressive of all changing the program code to work with different road speed sensors. Plus they say their is more improvements to come, thanks Colin and Dan.

[SteveSPG]

Quinny

when on the rr at pro tuner, we lost about over 100 ftlb when we had insufficient ballast (i.e. drums of water) in the boot of your griff. infact the boot was about full of those 20 ltr drums before we finally got runs that didnt wheel slip!

I've absolutely no doubt that you've (and others) some element of wheel slip effecting the numbers.

[MPoxon]

stevesprint what is your torque figure and modifications and I will add you to the RR wiki

[stevesprint]

spitfire4v8 said:

any idea what the blip in the fuelling is at the top end? noticed it's on the tvr power graphs too so definately something consistent. It's certainly a safe mixture at 12afr.

Jools,
In my AFR graph below I have a similar glitch at 6,100rpm. The glitch is more obvious in this graph because I specifically asked the rolling road owner for a longer run so I had more AFR samples. Please note I've blanked out the bhp figure as it’s incorrect due to experimenting with different ignition advance.



In my particular case the glitch is caused by not smoothing the extended RPM table. The RPM table is used to calculate smooth AFR transitions between two AFR RPM set points.

This second graph shows the smoothness of the RPM table (not AFR) and you can see one glitch at the same RPM point as the AFR glitch.



Once again thanks to Colin and Dan.

[pjac67]

OK , so here's my maps from last Saturday on the new 5.4:



Here's the map from the day before (conservative RR?) after full mapping session /RR once the new engine was run in that week:


All in all the same or less than my old 5.0 although it feels a bit quicker...?

[macdeb]

Seems many favour SRR, I wonder why?

[QBee]

macdeb said:

Seems many favour SRR, I wonder why?

I went there because my friends said it was reliable and accurate. It's a full dyno dynamics set up, concreted in (or at least it was last year - they have moved since).

My 5 litre engine, cross bolted and infernally balanced, stage 3 heads, larger everything induction-wise, bigger injectors, fully decatted, stealth cam, lightened flywheel gave 300 bhp at SRR, and 330 torques. TBH I was disappointed, but believed them.

Peter got 357 bhp on the same day, same session as me. Now you see why I question the results on the portable RRs. I know they are all Dyno Dynamics, but something isn't making sense to me.

I had a decent chat with Jools on Saturday, and we seemed to conclude that wheel slip and imperfect tie-down, not arse-uppedness, was the likely cause of low readings. I will take mine to Jools' portable RR some time soon, it's only 30 miles from mine, do a power run with 2 blokes sitting on the boot and the tyres over inflated, and see what we get. If Peter ends up there again any time soon, we hopefully will do the same with his car (if he agrees) and see what difference it makes, as we know what readings he got there last time.

[macdeb]

QBee said:

I went there because my friends said it was reliable and accurate. It's a full dyno dynamics set up, concreted in (or at least it was last year - they have moved since).

My 5 litre engine, cross bolted and infernally balanced, stage 3 heads, larger everything induction-wise, bigger injectors, fully decatted, stealth cam, lightened flywheel gave 300 bhp at SRR, and 330 torques. TBH I was disappointed, but believed them.

Peter got 357 bhp on the same day, same session as me. Now you see why I question the results on the portable RRs. I know they are all Dyno Dynamics, but something isn't making sense to me.

I had a decent chat with Jools on Saturday, and we seemed to conclude that wheel slip and imperfect tie-down, not arse-uppedness, was the likely cause of low readings. I will take mine to Jools' portable RR some time soon, it's only 30 miles from mine, do a power run with 2 blokes sitting on the boot and the tyres over inflated, and see what we get. If Peter ends up there again any time soon, we hopefully will do the same with his car (if he agrees) and see what difference it makes, as we know what readings he got there last time.

That will be interesting to hear the results.