DTC's came back

[Gorman]

..i read the sniper thread a while ago, don't remember which device it requires. I'm using an ELM 320 pass thru logging tool and several free OBD 11 programs....none of them as comprehensive as SCT stuff. G.

[cpapashley]

Originally Posted by Gorman

..i read the sniper thread a while ago, don't remember which device it requires. I'm using an ELM 320 pass thru logging tool and several free OBD 11 programs....none of them as comprehensive as SCT stuff. G.

The ELM320 system will only read, and not write. The sniper writes, as does the SCT. The good thing about the sniper is that it works with all eecv systems, and they seem prepared to make some effort to provide tuning support. They have a simple template they can sell you so you can tune yourself. I have a tuner coming up to Brisbane soon from down south Melbourne. He is happy to see if we can get something working. The fact you can read through the elm320 means that sniper should work for you too. I would find out if there is someone close to you that is a dealer.

I do have some pictures of my exhaust somewhere.....

ahhh here is the thread....

Mazda MPV '00

[SpookSVT]

Originally Posted by cpapashley

Must have missed your point on the ltft will check that tomorrow.

I will post up a pdf I have logged, seems to show interesting changes especially round the 5800rpm mark, wondering if some sort of reversion is occurring?? or is the cam profile useless??

Check the calibration first but the header priamary/secondary lengths could be wrong. Looks more like a calibration issue though.

[cpapashley]

Originally Posted by SpookSVT

Check the calibration first but the header priamary/secondary lengths could be wrong. Looks more like a calibration issue though.

So I check the calibration by....???

Sorry for the newb like question but being able to datalog is all so new to me. Checking the calibration sounds like something i would need a piece of equipment for, or can this NGS system do that in some way??

always happy to learn new skills...

[SpookSVT]

Calibration and tune are synonymous to me...

See if you can datalog the A/F ratio and check if there is a dip/spike in the fuel curve. That might be causing that loss of power around 5800RPM.

When you go to tune and it seems your throwing large amounts of fuel at it to get the curve back in shape, this could be an indication of over scavenging. There is an over abundance of low pressure present at the exhaust port at exhaust TDC/overlap. Decreasing overlap or changing pipe lengths to tune a different RPM would remedy this.

Did your fabricatior build to fit or are these tuned to a specific RPM? Pipe lengths and diameter would help as well.

[cpapashley]

Originally Posted by SpookSVT

Calibration and tune are synonymous to me...

See if you can datalog the A/F ratio and check if there is a dip/spike in the fuel curve. That might be causing that loss of power around 5800RPM.

When you go to tune and it seems your throwing large amounts of fuel at it to get the curve back in shape, this could be an indication of over scavenging. There is an over abundance of low pressure present at the exhaust port at exhaust TDC/overlap. Decreasing overlap or changing pipe lengths to tune a different RPM would remedy this.

Did your fabricatior build to fit or are these tuned to a specific RPM? Pipe lengths and diameter would help as well.

Tune...I wish, hopefully soon though, at the moment only datalogging. Will be getting a wideband when I finally get the ability to tune.

As far as the headers, I specifically requested that they be best throughout the rev range especially peak torque on to redline. Now I know that he requested engine size/combustion chamber size to work out the size of the individual primary pipes. Now he also worked out the equal length secondary pipes based on the same information. Not too sure how he did all that really, at that point just paid the money for the guy that came most recommended as able to construct a set of headers to suit my vehicle. His only comment to me was that with v6, he found the best gains were had with equal length primary and secondary pipes. He felt it was vastly superior to just a set of primary pipes.

If you can direct me to somewhere as to what formula he is likely to have used that would be great.

Keep in mind at the moment I still have the standard CAT



That huge thing and the rest of the exhaust is standard. Which will be getting updated with a hi flow metallic cat and a straight through exhaust.

I am hoping that if it is problems it is caused by the rest of the back pressure in the exhaust. What do you think??

Will clean the MAF, and have another run in the next week to see if I can see something. I will also log the MAF voltage, part of the problem is the speed with which it updates, but will reduce the number of inputs to see if I can get a better picture.

Really appreciate your input spook.

[SpookSVT]

I'm sorry, I thought you posted a power curve. That won't be the case then...

There is quite a few formula. Temperature of the medium in which the wave passes through will have a significant effect on the speed of the wave and thus the length of the tube. There's the ones I have from 'Scientific Design of Exhaust and Intake Systems' which are a bit complex and I don't have access to tools to get some of the required information (EGT, contents of the exhaust gas, etc..).

So to simplify the ordeal I have a header design program which is in the 90+ percentile in accuracy. There are some more basic formula available.

Also, an incorrectly tuned priamry length can return a positive pressure wave at overlap which can hurt cylinder filling.

You can try dropping the exhaust system after the y-pipe and then datalog to see if that dip clears up. Then you would know if it is indeed backpressure.

[cpapashley]

Originally Posted by SpookSVT

I'm sorry, I thought you posted a power curve. That won't be the case then...

There is quite a few formula. Temperature of the medium in which the wave passes through will have a significant effect on the speed of the wave and thus the length of the tube. There's the ones I have from 'Scientific Design of Exhaust and Intake Systems' which are a bit complex and I don't have access to tools to get some of the required information (EGT, contents of the exhaust gas, etc..).

So to simplify the ordeal I have a header design program which is in the 90+ percentile in accuracy. There are some more basic formula available.

Also, an incorrectly tuned priamry length can return a positive pressure wave at overlap which can hurt cylinder filling.

You can try dropping the exhaust system after the y-pipe and then datalog to see if that dip clears up. Then you would know if it is indeed backpressure.

Found this on line

Principles of Exhaust Header Design - HCP - Pontiac Forums

So I will check out the primary's and see if they follow this formulae at all.

If you have anything different, maybe just pm me with the formulae. When I get under the car to change the o2 sensors in the next week, I will take some measurements of what I have. I guess in a way it is all after the fact, but at least I can confirm if the extractors are hurting or helping.

As far as dropping the exhaust, only just over a week until I get the rest of the exhaust on, i think I will wait till then, the neighbours will appreciate... my patience.

[Gorman]

Originally Posted by cpapashley;I do have some pictures of my exhaust somewhere.....

ahhh here is the thread....:biggrin:

[URL

http://www.newcougar.org/forums/2-5l-duratec-performance/101329-mazda-mpv-00-a-2.html[/url]

Hey A. nice job. Have you thought about a true dual exhaust system using two stock cats instead of one sports cat ?,, G.

[cpapashley]

Originally Posted by Gorman

Hey A. nice job. Have you thought about a true dual exhaust system using two stock cats instead of one sports cat ?,, G.

Sorry to hijack the thread there G, interesting thought, but for me I think in australia that would cost easily double what I am proposing. I am just happy that I can get this for around the $500aud. Standard CATs cost the same as the hi flow I am getting. Two silencers etc etc just would blow out the cost for me.

I am pretty sure with the 2.5l the 2 1/2" single should be fine.