I want power all over the rev range

You best get rid of that golf ball sized turbo you have then

Touchy

Im also not a huge fan of WI. They are very tempermental and only seem reliable for a short time unless serviced regularly.

Are you sure the turbo isnt in-efficient at that boost? I personally dont think removing your bumper is going to cut the temps by anything over 10c.

Perhaps the 2871 is generating a little too much heat at 1.7-2.0 bar?

Good results though, and that OMEX system is good enough to cater for the intake temps being high.

Dropping the boost down doesn’t really change the temps. Turbo is ok to run at 1.7Bar but its keeping the temps down which is my new hurdle. The bottom line is that my intake system is completely different from the coupe. The coupe has plenty more room to play with, I wish I could run the pro alloy kit but it’s not going to happen. I have compromised the intake system and now I’m paying for it . I think I have no real choice but to splash out for a proper Aquamist system but I’ll leave that for the summer

Any ECU should be able to cater for temperature compensation it’s very important.

Sounds like your intercooler is a real problem then.

Wont a pro alloy fit in there? Surely it will fit behind the bravo bumper?

Not a chance . I'll show you next time I pass by.

would a chargecooler kit be better suited?

Yep, as I have said already - 72 degrees charge temps with that level of boost at the top end will KILL the power, even if you are not getting det.

Using water injection will protect you from Det - or stop det if there is not other way of doing so running high boost, but IMO it's a bodge job to bring down temps.

Inconsistent RR set up doesn't help your claimed figures......

The first graph is ran in 3rd gear, the second graph is ran in 4th?? Therefore the comparison isn't accurate. This probably explains why your peak figures tail off earlier........

Where were the readings for the Intake temp taken from, the one's I am referring to are the one's recorded on the graph (IT 35)?

Jules.

Actually you’re correct to notice that but wrong to assume that the tests are inconsistent. I ran the car in 3rd to begin with then with the graph being so different we changed to 4th to see if the difference could be found and there was no difference. 4th gear just happen to be the one printed off when I left, believe me the 3rd gear runs were exactly the same as the 4th gear runs. The gearing doesn’t affect "shoot out mode" power figures. The whole point of “shoot out mode” is to be able to compare dyno graphs regardless of environmental changes including gears as the operator is NOT able to fiddle any setting when in this mode, this is displayed as “SHOOT_6F” on my graph. In fact if your theory was correct then running the car in 4th would give me less torque.

IT is a probe that is pushed inside the air filter. AT is ambient in the dyno weather station.

J you can fiddle the DD shootout mode, not saying yours has been (before you jump down my throat!!), just saying it is possible as with all dynos, just need to know how.

Anyway look forward to having a blast in your car one day, should be great fun

What makes you think I would do that

The DD manual says it can’t be done but I'm sure there are ways to hack dynos; for me it offers no benefits, I'm not one for pub figures I like to test make a change and re-test so consistancy is key.

J - your cooling is very suspect - at TOTB, I was starting a run with over 30 degrees showing, but after a mile of 2 bar, I was still only showing about 60 degrees

I don't think the temp can right. Sure underbonnet temps are gonna be quite high, but the temps are only going to go up after the air filter(turbo adds heat but fmic can never make it lower than ambient). Sure a more accurate of inlet temps is at the throttle/plenum anyway.

If it is genuinly that hot I'd be measuring post fmic temps too. Perhaps you can section off where your filter is so it's gets nice cold air

Hang on - J is that intake temp reading taken pre or post IC?

pre-IC the temps will be over 100°C AFAIK

Sure - I mean if a temp probe is put in the filter then I dont see how this is an accurate reflection of the intake post IC and Turbo...

Hi,

I disagree with what you are saying.

A Dynodynamics Dynomometer will be running out of it's fixed parameters in 4th gear on a Coupe. In order to obtain an accurate torque/bhp figure the optimum for peak is set around the equivelent of the engine running at between 100-105mph. If ran in the wrong gear then the curves deviate away from what is correct as the dynomometer cannot calculate quick enough to compensate, as such you see that if you overlayed two runs, one in 3rd and then one directly after in 4th, that at a certain point in the rev range the curves on the 4th gear run will climb more steeply and reach their peak earlier. This appears to be exactly what your two graphs show.

Shootout mode is only consistent with other variables staying that way, a different gear will make a difference and parameters such as IT, rolling radius, gearing correction can be altered.

Have a look at the two graphs below, one is ran in 3rd the other in 4th, you can see that the peak torque moves and graph climbs more steeply after a certain point in the rev range. This results in higher figures with the torque increasing beyond the 3rd gear figures and ultimately then the curves drop off earlier than they should, if you look at the 3rd gear results the curves keep on going well past 7k rpm which is correct for this engine and the way it was mapped.



3rd Gear

4th Gear

Ambient Air Temp (AT) is the environment
Intake Ait Temp (IT) is at the air filter
72C is at the intake manifold at the ECU air temp sensor

So at 1.7Bar my air temp is 25C at the filter and 72C at the inlet manifold a rise of 47C.

@ Cyclone
You do know my two graphs are with different setups. It’s not a before and after mapping on the same day. There is a four month gap in which I have made some modifications.

You give a long explanation then ask me to compare your two graphs which have completely different RPM, BHP & Torque scales? Plus different tyre pressures, “Shoot_8” then “Shoot_8F”. One was done on 18/2/2006 and the other 23/6/2006 that is hardly a run done in 3rd then straight after a run done in 4th is it, so your graphs don’t actually show a difference the gearing makes? Those two graphs are so different it completely contradicts the point of consistency you’re trying to make.

Yes I do.

No my graphs don't contradict what I am saying at all, they are just an example to show how 3rd and 4th gear give different results, you don't have to believe them but I know they are right and have seen many hours of cars running on a DynoDynamics Dyno.


Yes the scales are different and the parameter set up for 8F v 8 is marginal albeit less than 3 bhp across the rev range at plus 400bhp. There was a gap in my graphs of a few months but the set up was almost identical, I can't currently find the exact same day comparison graphs so put these up just to prove my point.....which you seem to be missing?!

When ran in 4th the results deviate away from what the RR correctly records in a 3rd gear run, this happens at a certain part of the rev range depending upon the engine being tested. On my graphs you will see a much steeper increase in power/torque from 3750rpm to peak, see here:

3rd Gear at 3750rpm
250bhp
345lb/ft

3rd Gear peak figures
420bhp at 7050rpm (70bhp increase over 3300rpm)
385lb/ft at 4900rpm (40lb/ft increase over 1150rpm)

4th Gear at 3750rpm
250bhp (same as 3rd)
350lb/ft (similar to 3rd)

4th Gear peak figures (occur earlier)
451bhp at 6600rpm (31 bhp higher than 3rd gear + 101bhp increase over 2850rpm)
406lb/ft at 4900rpm (21lb/ft higher than 3rd gear + 56lb/ft increase over 1150rpm)

The engine used in my example is a 4.5 V8 Cerbera engine where it was at it's optimum at 420bhp. It had been on these rollers for over 100 runs and I know the set up very, very well. I also used the same RR for my 335d and know exactly how to manipulate or enhance figures if I needed to. The reason for the run in 4th gear was to show how the RR can give false figures if a car is ran in the wrong set-up. 3rd and 4th gear runs are not comparable. I am not knocking your claims and wouldn't have questioned anything had you used 3rd for both runs.

Jules.

I can't be bothered to go into this any further. Just like you know your car I also know mine very well. Its right of you to point out that both “printouts” were done in different gears, but I'm telling you the runs were done in 3rd and 4th immediately after one another and it made NO difference. I am happy to say that the difference has nothing to do with the gears, whether you choose to believe this or not. The extra torque was gained due to there being a manifold leak, the DV round the wrong way and possibly changing from 17" to 16" wheels. It’s not like my results are out of this world and I’m trying to blag figures in fact you could say I’m underpowered compared to others with similar setups. For example Nigel had 405ft/lb with 385BHP on the same turbo with a very similar setup. If you read through my project thread you will see that I am very honest when showing my dyno results. I have nothing to hide when it comes to results. If I lose power, I lose power. If I gain power I gain power.

Got to agree with you there J.

Quite a few years back, there was a RR day at G-Force (when Chris used to work there) in MK which must have been back in 2003 / 2004 and there was a few of us there. JohnS came as well and i distinctly remember his car was run on the RR in 3rd gear. John asked Chris to run it in 4th gear straight afterwards which Chris said there was no point, makes no difference, but he still did it anyway, and guess what, the results were the same. This was also done on a DD Dyno.

So i'm in the 3rd or 4th gear makes no difference camp.

I've had the same experience at the Racing Line in Halifax a couple of years back too.

Fair enough and all points taken....

Like I've said I know the DD pretty well and have done many tests to provide accurate rr data, here's the old thread off PH for when I posted about 3rd v 4th gear runs on a Dynodynamics RR.

http://www.pistonheads.co.uk/gassing/top...&nmt=Latest Rolling Road Result&mid=27881

For me seeing the two graphs on here there are too many similarities as to why I believe the graphs to not show an accurate reflection, especially the way the power/torque tails off and the earlier delivery. Tailing off early can also be attributed to how tightly the car is strapped down, the tighter it is strapped down the lower the figures, less tightly then the power figures are higher but tail off more quickly.

Just my opinion and not putting down the gains made.

Jules.

Some of those Cerbera RR figures debates are vintage Pistonheads stuff

Having read through them (and M3 RR discussions and results, and other stuff) I'm firmly in the camp that gearing makes a difference to the result.

Please don't get me wrong J, I think the figures are impressive (regardless of which gear you're in) Do you have at-the-wheels graphs that we can look at too?

Neal