David Platt short exhaust 2004

Twiz003 said:
Hi Sleeves,
Would you have a ECU tune that would help with a 2004 and the DP shorties? anything better than the Tor tune. might also look at a Ramair intake if that helps?
Cheers
Click to expand...

PM me with your VIN no and I'll have a look. No promises as the DP "exhaust" is really just a dump pipe, to stop backfire on the throttle off its a matter of either enriching up the mixture till it cannot backfire, or cutting off the fuel, enrichment is safer, but it has to be done at the correct point. That's why the TORS "tunes" wont work well.

I have a MAP from a D&D system I had on that used to backfire like a B before I loaded it. Not sure if it will load to your ECU though as mines an 05 The pipe was longer too and I had it baffled more than the OEM D&D pipe to shut it up so gas flow was not as good.

Watch this video. Young guy, describes things clearly. . You have a very short exhaust so the gases are hot and mix with the air in the pipe and detonate. Sorry but in IMO for everyday riding a stubby exhaust is not the best option. For a rail, or funnycar, with savage cam overlap, wild compression, nitro fuel, no concern for engine life or economy they are perfect.

Can only try take it your OK with loading maps?
 
Thedogsbollocks said:
Shame on the Exhaust expert D.P then! This is a major part of his products sales pitch. He should know better or be called out as a bull****ter! I was duped by this.
Click to expand...
To be fair to DP,
My bike ran fine with his mufflers and the Tors tune.. only got a little "poppy" after I added the crossover pipe but that also made a bigger difference to how much better the bike ran otherwise. But its true, I was under the impression that quick 12 minute special would take care of the mapping for the addition of the crossover which it really couldn't. The Ramair guys tell you you will need a new map with the added airflow.
 
Allan S said:
Mine go past the shock bolt not outlaws
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To me that exhaust is not short. Shorter than stock yes, but if the ID is stock sized to fit thee stock header, it seems odd there is cold air making it's way back to the sensor.

Please don't read anything of an argument into my post. Penner is a great tuner and Paul a craftsman of great quality, I admit they know much more than I in these regards.

My only interest is my current cans are about the same length, maybe a a tad shorter and have been thinking of ordering a PC V/AT combo and could run into the same issue.
 

I dont think its the length so much as that they are pretty open as well.. The pressure waves cause a kind of sucking effect with the airflow and thats where the faulty reading comes in. I am thinking of moving the sensor onto the crossover and trying it there.

When I spoke to Chris at Power commander he knew instantly what the issue was so obviously its common.
 

If you wait a few weeks I should be finished with the PCV and AT once I refine Ulf's map on the PCV and import it to the ECU. Then I'll sell them to you at a discount- I just put them on about 6 weeks ago?
 
Hi


Hi Penner,
A thought on the subject of the sensor reading wrongly at low revs. Ive spent 40y in industrial ( not automotive!) problem solving.

The sensor is fitted in a pressurised area of the exhaust system. For air to pass the sensor it would have to enter earlier up in the flow path, but i would doubt that as all the joints should be sealed otherwise you would hear a leak.

An unknown factor is the sample rate that the sensor operates? and the ECU operates to determin the data.
I would suspect that the std or close to standard type of pipes produce a backpressure that is still there at lower revs, this would give a smoothing effect to the sensor read/Ecu and and allow a more average read.
By removing the back pressure as you said there is more of a pulse wave from each cylinder. If the sample rate of the sensor is as high some of the industrial stuff ive played with, then the sensor could be reading many many samples for each cyclinder detonation as it passes across the sensor face.
The sensor could then be seeing a much higher pulsing/wave effect with only a short section of that pulse at the what it believes to be the correct read. The rest of the reading could be way bellow what it wants to see and then alters the fuel input to compensate?

Had a few beers and probably talking ****e.....but heyho!
Atb
Twiz
 
Allan S said:
If you wait a few weeks I should be finished with the PCV and AT once I refine Ulf's map on the PCV and import it to the ECU. Then I'll sell them to you at a discount- I just put them on about 6 weeks ago?
Click to expand...

I am in no hurry, I cannot decide if I want new cans or the PC V first. Been trying to decide for a couple months at this point lol
 

Thank you.
I know a few things about - but I am not that deep into O2 sensors.
But after Allan made the "towel test" I am very sure that it is a mainly a matter of simple air backflow.
It may be that the 3-1-2 system with different length in the two exhausts left/right causes an interference that is part of the problem.

Prost
Ulf
 
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