706 replies to this topic

[Bargi]

I think 54 deg is optimistic. I think that is probably from a single run after the system temps have dropped. I think after 3-4 gear changes that would be higher. A data run from a track session or few pulls on the dyno would be better. 

 

 

 

At the very end of the day at Snett we went out and I hooked up a bluetooth OBD reader and Torque.

He pushed hard at the start but backed off a bit after about a lap and took it a bit easier, temps were always between 65 and 75 degrees but we were only out for maybe 2-3 laps.

Edited by Bargi, 11 October 2015 - 08:38 PM.

[Matthew Bentley Racing Ltd]

Has anyone checked for mice in the air box?

 

They could be nesting and holding on for dear life, as the revs rise they cant hold on any more, and at 7k they get sucked up and block the intake. When you let off to change gear they fall back down and the cycle repeats. 

 

[CHILL Gone DUTCH]

Martin is M62 Not Harrop so temps are generally better

[CHILL Gone DUTCH]

Martin has also a 2.5 " exhaust with a CAT So his pressure will also generally be higher than a 3" system with No cat Which is a restriction also I'm a firm believer that martins issues is a combination of things From my own experiences I discovered everything has to be working to get the best out of these sc setups

[The Batman]

has martin got a new exhaust now?

[ArticMonkey]

Has anyone checked for mice in the air box?   They could be nesting and holding on for dear life, as the revs rise they cant hold on any more, and at 7k they get sucked up and block the intake. When you let off to change gear they fall back down and the cycle repeats.   

I believe this is also the case with your phone. Mice are running off with it and deleting your missed calls list. 😑

[CHILL Gone DUTCH]

has martin got a new exhaust now?

The one we put on at zandvoort

[smiley]

 

has martin got a new exhaust now?

The one we put on at zandvoort

 

 

That's a 2.25 at best.

 

Did survive a 330hp harrop though  

[The Batman]

2" its a standard with a turbo cat

[Exmantaa]

As Joe said; a restriction (intake or exhaust) should limit the max power and not causing it to drop of a cliff...

 

It's a real interesting case this one, only a bugger for Martin..

 

So far we've heard the following possibilities;

- exhaust restriction?

- intake restriction?

- too high IAT's, causing ecu to retard ignition and loosing power?

- too much knock, causing ecu to retard ignition (there is ~3 degrees knock >5K...)

- Soft rpm limiter in action?

- Sparkplug or Ignition coilpack issue?

- Fueling issue (pump / injectors)?

- valve / cam problem? (cam timing / valve float? Think Martin has DBilas springs fitted)

- Mechanical engine problem? (should be audible and cause high friction lossesn/engine temps me think?)

- Engine electrical / sensor issue? (maybe external crank trigger looses the plot at high revs?)

- ???

 

Edit;  - forgot the possible PCV oiling issues / blowby playing a role here too?

 

Now the collective can shoot...

Edited by Exmantaa, 11 October 2015 - 09:44 PM.

[Exmantaa]

2" its a standard with a turbo cat

 

No  It's a "Zandvoort special" with a modified Turbo cat.

2.25 on it's smallest point and pulled 330HP with a Harrop...

[vocky]

So far we've heard the following possibilities;

 

 

- exhaust restriction - U bend and backbox size / type ?

- intake restriction? - alloy tube fitted so not sucking in, but air filter size ?

- too high IAT's, causing ecu to retard ignition and loosing power? - quite possible

- too much knock, causing ecu to retard ignition (there is ~3 degrees knock >5K...) - this needs looking into

- Soft rpm limiter in action? - needs checking

- Sparkplug or Ignition coilpack issue? - possible, but less likely

- Fueling issue (pump / injectors)? - aftermarket pump fitted - is it duff ? - fuel pressure needs checking

- valve / cam problem? (cam timing / valve float?) - vernier'd cams and dbilas springs fitted

- Mechanical engine problem? (should be audible and cause high friction lossesn/engine temps me think?) - possible, but less likely

- Engine electrical / sensor issue? (maybe external crank trigger looses the plot at high revs?) - solid mounting bracket for crank sensor, but a possiblity

- PCV oiling issues / blowby playing a role here too? - certainly possible, temporary fix - blank off PCV port under cam cover

 

 

Edited by vocky, 12 October 2015 - 07:16 AM.

[fezzasus]

Similar to the point about exhaust restriction, fuel restriction would also cause a power plateau, rather than it dropping off. 

 

What does Martin's manifold air pressure do when the power drops?

[MartinS]

To help answer some of the questions,

I have  change up lights fitted so I know what revs I'm hitting above 7000. They go green at 7000 and flash red at 7500. I tried them at different revs and they are accurate.

To test if there was an unknown rev limiter I change my limit in the software to 7800 and matched it with the lights, it still tailed off at 7000.

My normal limit set in the software is 7500.

 

I was using a brand new Apexi air filter but to knock that out of the equation, went back to a big cone filter I have had on the last 2 years (it was freshly cleaned), but I still have a 7000 fall off.

 

Sparkplug gaps have been checked and are correct. I could maybe make the gaps smaller but by how much?.

I have tried the 6's and 7's. 7's it ran no better but wouldn't start well,so have gone back to 6's.

 

What is best next re the pcv valve, replace the one in there in case its blown or blank off?

 

How easy is it to check fuel pressure?

 

Martin S

Thanks to all of you for your time and help with this.

[fezzasus]

Blanking the PCV would test if it's the PCV valve that's failed, however if it has, you will want to change it to a working PCV to control oil loss better. If you're not doing the work yourself, it's quicker and possibly cheaper to have it changed to a new PCV valve rather than have two sessions.

 

[siztenboots]

so what are the plug gaps you are using?

[Exmantaa]

[font="arial, helvetica, sans-serif;"]So far we've heard the following possibilities;[/font]

[font="arial, helvetica, sans-serif;"]( I only can see the logged parameters during the power run, but ideally Martin should do a full ecu log during a pull to 7,5K. Than we can check all engine parameters.)[/font]

 

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- exhaust restriction [/color]- U bend and backbox size / type ? > should show in his log as a rise in MAP, but that is flat @ ~195KPa[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- intake restriction?[/color] - alloy tube fitted so not sucking in, but air filter size ? > should show in his log as a decrease in MAP, but flat @ ~195KPa[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- too high IAT's, causing ecu to retard ignition and loosing power?[/color] - quite possible > IAT's during that run are not excessive. Also Ignition advance is constant in the log[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- too much knock, causing ecu to retard ignition[/color] (there is ~3 degrees knock >5K...) - this needs looking into > Ignition advance is constant in the log up top, but his log shows knock and maybe there is some ecu failsafe action going on at high revs? => revise ignition map with less advance and test.[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- Soft rpm limiter in action?[/color] - needs checking > He already upped his hard rev limit with no change...[/font]

[color=rgb(255,0,0);] [/color]

[color=rgb(255,0,0);][font="arial, helvetica, sans-serif;"]- Sparkplug or Ignition coilpack issue? [color=rgb(0,0,0);][font="arial, helvetica, sans-serif;"]Possible, but less likely > He changed plugs with no results. Should try out a known good coilpack to rule that one out..[/color][/color][/font][/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- Fueling issue (pump / injectors)?[/color] - aftermarket pump fitted - is it duff ? - fuel pressure needs checking > Any lack of fuel should show as a lean mixture with possible knock etc. He has no wideband fitted, but his O2 sensor shows 1,1v, which indicates a rich mixture..[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- valve / cam problem?[/color] (cam timing / valve float?) - vernier'd cams and dbilas springs fitted > Easy check if springs and lifters etc. are still OK?[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- Mechanical engine problem?[/color] (should be audible and cause high friction lossesn/engine temps me think?) - possible, but less likely[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- Engine electrical / sensor issue?[/color] (maybe external crank trigger looses the plot at high revs?) - solid mounting bracket for crank sensor, but a possiblity > Can be a gap issue with the VR sensor & trigger wheel, only playing up at high frequency / revs... (what's the gap?)[/font]

 

[font="arial, helvetica, sans-serif;"][color=rgb(255,0,0);]- PCV oiling issues / blowby playing a role here too?[/color] - certainly possible, temporary fix - blank off PCV port under cam cover. > Try this...[/font]

 

 

 

 

Edited by Exmantaa, 12 October 2015 - 10:24 AM.

[ArticMonkey]

I personally think it's something hidden in the software that Peter hasn't mentioned. He does this for non forged engines as a fail safe. I'll be contacting him today as mine drops off at about 6800rpm in the same rate as Martins. Peak power was at 6800rpm also.

[CHILL Gone DUTCH]

I would imagine Martin is getting bombarded with different ideas of what is happening with his setup Martin by his own admission is not going to be doing much of the work himself So might be better off if we come up with a list of things to get sorted in order @ no 1 I would suggest getting a wideband installed for his WOT mapping as suggested by peter for anything over 250hp As it could be a good reason why the car is not making good power top end If anyone has a idea of a better idea of what to do first please shout up so Martin has a more of a idea of the next step

[CHILL Gone DUTCH]

Just a other idea in the mix Is it possible there is some kind of resonance happening and causing issues