Not So Good Rolling Road Result

[Aberdeen Al]

Getting a stage 2 head, Schrick cam & larger injectors (450cc) fitted today / tomorrow but before the guy started the work he did a power run on my MCS...................very disappointing figures:

Corrected Power: 196.5 bhp
Engine Power: 198.6 bhp
Wheel Power: 140.7 bhp
Drag Power: 57.8 bhp
Max Power: @ 6475 rpm / 122.9 mph
Max Torque: 4555 rpm / 86.4 mph

My car is fitted with the following:

GTT220+
GRS Intercooler
GTT manifold
JCW exhaust
JCW injectors
+1% lightened crank pulley
Lohen enlarged throttle body
Standard map

The above may explain my disappointing 30-70mph in 3rd gear times.

Will get the car dyno'd again after new head fitted!

[Paul]

So they guy doing the head, cam and injectors was responsible the disappointing "before" dyno run? Call me an old cynic, but I'd imagine you may look forward to a REALLY good improvement in the "after" dyno run if that was the case.

If it was an independent and non-associated dyno, then ignore the above completely.

[Loui]

Thats is disappointing my car with JCW kit (210), 17% pulley, 1% crank, GRS, Miltek mani an Custom magnaflow made 191 at the wheels have you checked you bypass valve? Is the compression ok? I would expect a fair bit more TBH

[Paul@1320]

Were the runs done in 5th and what dyno is it??

[Lucky Dave]

I think you may have another fault and would also see low figures even if the car was standard.

I have just played with a modified S which had all the right parts but was just down on power, It turned out to be one simple part that was not working correctly, that replaced and the car felt like a new one with much more power.

I have not stated the part that was needed because I would not want to lead everyone to rush out and buy one single item! Correct diagnosis is the key, and can only be done with the right equipment.

Im sure once the additional parts are fitted the genuine fault will become apparant.

6475 rpm / 122.9 mph.......................yes that looks like 5th to me!

[Rigsey]

Something sounds amiss.

Have you got anyway of checking your boost pressure?

Slipping belt maybe?

I have a slightly lower GTT spec than you + GRS IC (see signature) and had my car dyno'ed on a dyno dynamics rolling road in April on a warm day with a very small IC fan and recorded: 211.7 bhp flywheel (at the wheels = 176.6)

Run was conducted in 4th gear and operator did not go above 6500 rpm.

[Revolution Mini Works]

Quote: Originally Posted by Rigsey (original)

Something sounds amiss.

Have you got anyway of checking your boost pressure?

Slipping belt maybe?

I have a slightly lower GTT spec than you + GRS IC (see signature) and had my car dyno'ed on a dyno dynamics rolling road in April on a warm day with a very small IC fan and recorded: 211.7 bhp flywheel (at the wheels = 176.6)

Run was conducted in 4th gear and operator did not go above 6500 rpm.

wow... a 20% correction factor......
I guess it's all about the numbers

[Rigsey]

Quote: Originally Posted by Kumho Kid (original)

wow... a 20% correction factor......
I guess it's all about the numbers

Whats the correct correction factor then?

[Rigsey]

Quote: Originally Posted by Rigsey (original)

Whats the correct correction factor then?

Actually scrub that, just found an explanation from Roland:

http://www.mini2.com/forum/engine-dr...orsepower.html

Kumho Kid: In my opinion at the end of the day its not all about the numbers it about what it drives like

I posted my numbers purely for Aberdeen Al to compare against as we have similar mods I'm sure they will be taken with a pinch of salt as we used different dynos on different days, etc.

[Paul@1320]

Al, I would concertrate on getting the engine making what it should be first before fitting the head otherwise you might cost yourself a lot more money in the long run.

[minicabrio]

He probably let 15psi out the tyres before sticking it on the rollers

Before investing major money in any mod I'll aways take a visit to an independant rolling road, then have it dyno'd after aswell Shame you're up in Aberdeen as we have Surrey Rolling Road down here who are very highly regarding in the local car enthusiast groups....

Best of luck with it all still though

[Loui]

Quote: Originally Posted by 1320autos (original)

Al, I would concertrate on getting the engine making what it should be first before fitting the head otherwise you might cost yourself a lot more money in the long run.

You only have to look at your headgasket failure which took a chunk out of the block to reaslise that get it checked before adding too

[roland2003]

Hi Guys, yes all the above is very valid. We had a car in last week that had had a GTT220 fitted a few months ago. It was only in for brakes but I felt the car was very down on power. I traced to faulty bypass valve actuator. we fitted a brand new one (gtt tweaked prior to fitting), and the car gained approx 50 horse power.
Customer was very nice and even pm'd me a couple of days ago it read;-

'Thankyou Roland.'
'.......Thankyou Roland for repairing my EB Cooper S last week,the brakes are brilliant,and I cant believe just how much power Id lost with that valve problem.It had just gradually degraded over the last 6 monthsand I just did not realise how much zip the car had lost.Now I'm back finding I have to be judicious with the power...'

We have had many cars with this fault that have even been back & forth to the main dealer who say everything is correct. There computer diagnostics will not register any fault codes when the bypass valve actuator breaks 'the computer says no'
We can diagnose this fault in approx 5 seconds every time. There are other simple faults that cause big power losses, you dont need RR's nor diagnostics to find most of them.
These cars do benefit from a yearly checkup. TBH even if your car is in with us for other work (eg brakes) we'll often spot anything thats amiss. I did cut the old bypass valve actuator open......diagnosis? the spring inside had broken in half through old age fatigue.
Best Regards Roland GTT

[Paul@1320]

Quote: Originally Posted by roland2003 (original)

I traced to faulty bypass valve actuator. we fitted a brand new one (gtt tweaked prior to fitting),.

I did cut the old bypass valve actuator open......diagnosis? the spring inside had broken in half through old age fatigue.
Best Regards Roland GTT

What KPA was it seeing when it came in?

[k-huevo]

There’s no mystery to diagnosing a by-pass valve’s spring, operate the BPV arm with your finger and you can feel whether it snaps back or is rough. No need to cut anything, the cover of the diaphragm pops off if you want to verify the spring condition. What can not easily be seen is a cracked casing near the butterfly’s shaft; another failure condition of the early models.

Yes, one can’t ignore the under hood details if one wants to maintain optimum performance from a high performance vehicle. As an example, take a look at the #3 plug wire post on the coil pack, if there is any substantial mileage on the vehicle, you will find corrosion. Clean it with an abrasive or wire brush and apply dielectric grease; do the same for the other posts.