706 replies to this topic

[Matthew Bentley Racing Ltd]

I forget to say to Martin in the email, but me and Lee both think the drop in power at the top is probably the 2.25" exhaust system. No point reving past 7k.

[Matthew Bentley Racing Ltd]

Yes melted cat. Completely blocked. 

 

I don't know about more, the ignition is just mapped to peak torque now so will have a bit more over std maps.

[CHILL Gone DUTCH]

did you manage to get a comparison run matt so we can see how accurate the obdtuner runs are in comparison with the dyno 

[Zoobeef]

Makes sense for the symptoms but it'll be interesting to know the exhaust woes start to finish as wasn't that checked and replaced a few times :/

[smiley]

Yes melted cat. Completely blocked. 

 

 

The one that was in when it arrived at your workshop?  

[CHILL Gone DUTCH]

Makes sense for the symptoms but it'll be interesting to know the exhaust woes start to finish as wasn't that checked and replaced a few times :/

 

bit of background with exhaust 

martin had it repaired before zandvoort (flexi issues) but was by the time we got to zandvoort the flexi had gone again 

all this was on first down pipe 

 

we then swapped down pipe at zandvoort for one from frank 

the track day went resonably well but the car was not mapped, maybe just a fuel run from the previous down pipe (unsure of condition )

martin was not 100% happy with the car at zandvoort but considering the issues before he did very well 

 

after getting home thats when the inlet pressures started to increase and the power went down so this was probably the start of the blocked cat.

 

at this point the exhaust was passed as ok but we suspect not 

Edited by CHILL Gone DUTCH, 23 December 2015 - 08:50 PM.

[Zoobeef]

So, are we thinking a bad map from a leaking exhaust melted the new cat as the leak was then fixed? Hopefully this has sorted out the oil issue too. Bad for the oil industry though as I'm pretty sure Martin was keeping Shell in business.

[Matthew Bentley Racing Ltd]

Yes melted cat. Completely blocked.   

  The one that was in when it arrived at your workshop?  

Yes the one that was on the car when it arrived with me and Lee. No comparison. Don't even know how to do one lol. Just mapped it. Martin can do it and post up.

[CHILL Gone DUTCH]

Martin did plenty of fuel learn sessions and the fuel trims looked ok but llambda could of been damaged or anything 

 

its also a good idea to have a wideband installed for martins specs 

[Matthew Bentley Racing Ltd]

Martin did plenty of fuel learn sessions and the fuel trims looked ok but llambda could of been damaged or anything    its also a good idea to have a wideband installed for martins specs 

Lack of wideband made it hard to map low speed exhaust gas flow fueling.

[CHILL Gone DUTCH]

also if the exhaust is damaged in any way or form the lambdas cant do there job correctly so the mapping is never going to be right 

 

[leevx2.2]

Right pics of the cat

[mbes2]

Thats gotta be around 300BHP  ... Martins Lotus Evora order will need to be cancelled  

[CocoPops]

Dutch software says 500bhp

[CHILL Gone DUTCH]

Dyno power = 260bhp at wheels. Dutch Software = 350bhp at crank. Tongue in cheek guesses before anyone gets arsy

🙈😜😂😂

[CHILL Gone DUTCH]

Dutch software says 500bhp

😂😂😂

[mbes2]

I used this....for a guide

 

http://www.mk5cortin...calculator4.php

[smiley]

As much as i like all the willy waving on hp, i'm still slightly worried on the piston rings, with the decission not to open up the engine and look.

 

[Exmantaa]

We found ~17% drivetrain loss gave us comparable numbers, but depends on the rolling road calibration and also on rear tire spec & allignement...

 

Well, at least now Martin's high boost, heat and bad running issues are remedied with this dead cat issue (I think this exhaust was inspected and given the "ok" 2 or 3 times since the start of his problems ) and that curve looks very driveable.

But some isssues he started with are still there; the steep power drop after 6800rpm and still waiting on how the oil usage is now.

I hope that last one was initially caused by the pcv valve leak and after fixing that the exhaust blokkage played up. (that cat section looks very white inside. Ash from burned oil?) 

 

Powerdrop after 6800rpm is still a bit of a mystery. Power leveling off or slightly drop I would suspect a restrictive exhaust section, but not this steep drop in power and torque.

(And that same 2.25 downpipe, still including the cat section, was used on a Harrop 2.0 that had no trouble hitting the rev limiter @ 7700rpm. )

[Matthew Bentley Racing Ltd]

[quote name="Exmantaa" post="1835428" timestamp="145095642
Powerdrop after 6800rpm is still a bit of a mystery. Power leveling off or slightly drop I would suspect a restrictive exhaust section, but not this steep drop in power and torque.
(And that same 2.25 downpipe, still including the cat section, was used on a Harrop 2.0 that had no trouble hitting the rev limiter @ 7700rpm. )[/quote]

Yes strange drop off that fast. New I wasn't going to be able to save it. Either this it's the exhaust or maby worth Vocky moving the inlet cam.

Gives a mega Road engine though.