CSL6 7 Report post Posted May 31, 2012 Our M3 E36 3.0 race car engine seems to have lost its mojo from 5000 rpm onwards. The dyno printout shows normal power to about 5000 rpm and then the increase drops off to end up about 40kw less than it was at 7200rpm. The engine internals are all A1. We run std computer, std engine. We suspect a vanos issue but having difficulty pinpointing whats wrong. Any suggestions? Quote Share this post Link to post Share on other sites
hybrid 1043 Report post Posted May 31, 2012 Your Intake cam ECU target and actual target should match. Unfortunately there is no software around that will show you this however it is availible from the DME by other means. should look like this typically (sorry this is a s50b32 which has exhaust cam too) My point is the DME target, in your case intake cam target (ICT), should closely follow the intake cam actual (ICA). If not you have a bung cam position sensor or other wiring issues or probably seals are gone. Units for the cams are in degrees and on the primary axis, secondary is RPM scaling on this graph. Replacement seal kits are availible. Quote Share this post Link to post Share on other sites
nastnas 9 Report post Posted May 31, 2012 My Vanos Thread I did that a few years ago now, and jumped from 168 to 180kw at the wheels... It has a few pics of the seals that caused the problem.... Before doing that, I would get your DME scanned like hybrid has said... Quote Share this post Link to post Share on other sites
Greg111 13 Report post Posted June 1, 2012 Could almost bet that it would be the seals, mine was the same (although back then i knew no different) did the seals and made a huge difference. Quote Share this post Link to post Share on other sites
CSL6 7 Report post Posted July 24, 2012 Thanks guys...yes it looks like it was the seals. We replaced the whole unit with a second hand one at all seems to be back to normal again...yipee! Took the car to Taupo last week for a bit of testing and to try slicks for the first time. They made us about 1.5 secs quicker so into low 44's. The tyres were 2nd hand and seemed to be a bit hard for the car...Dunlop ex NZV8 I think...they seemed to "hop" sideways across the corners when really pushed, not what I expected and not that nice. Maybe our suspension is too soft for slicks? It works fine with DOT tyres. Quote Share this post Link to post Share on other sites
hybrid 1043 Report post Posted July 25, 2012 Moving to slicks is quite a bit different than DOT or road tires. The there a lot of differences in contruction. Slicks are also very sensitive to temprature and pressure changes. It is critical that the right start pressure are found and that you measure your pressure up throughout your laps. On the e30 I start at around 24 and build up to 30-31 PSI Anything over for me and I loose grip. ( this is weight dependant and compound dependant. Also unfortunately, Slicks go off. The could have to do with how many heat cycles they have had or how they have been stored. Taupo is a crappy surface as far as grip and slicks go compared to say Hampton. Work on tire pressures first then start to look at your suspension setup. Start to take measurements across the tire as it will tell you a lot. Attached is my track day race prep cheat sheet card. It has a Tab with a quick guide to reading slick temps. Not saying this is the be all and end all, but it works for me The tire pressures are even across all tires. If you wanted to get serious, you could have individual pressures for each tire dependant on the track and weather. Race_Sheet_v3.0.zip Quote Share this post Link to post Share on other sites
Jamez 2147483647 Report post Posted July 25, 2012 they seemed to "hop" sideways across the corners when really pushed. I had this issue with the e30 on slicks, found it was flogged rear bushes as when I fitted delerin bushes it stopped the shuffling. Quote Share this post Link to post Share on other sites
CSL6 7 Report post Posted July 29, 2012 (edited) "Slicks are also very sensitive to temprature and pressure changes. It is critical that the right start pressure are found and that you measure your pressure up throughout your laps. On the e30 I start at around 24 and build up to 30-31 PSI Anything over for me and I loose grip. ( this is weight dependant and compound dependant." Thanks for that...maybe it was a tyre presure issue. We were advised to get them up to 35-36 lbs hot so started at 30 lbs. We only had time for one run so had no chance to expeiment. I think the tryes are D11 Dunlops, same as V8's use anyway. Edited July 29, 2012 by CSL6 Quote Share this post Link to post Share on other sites
CSL6 7 Report post Posted July 29, 2012 I had this issue with the e30 on slicks, found it was flogged rear bushes as when I fitted delerin bushes it stopped the shuffling. Our rear bushes seem OK. Maybe it was pressures...what do you run yours at hot?We are thinking of going A class this season too as the DOT tyre cost in B is too high and I'd like to try something differant. Keeping the rest of the car the same except for weight loss through lighter wheels and brakes and no ballast. Will be well off the pace of the fast A's but should be able to keep El Preso Foxy under control!! Wish September would bloody hurry up! Quote Share this post Link to post Share on other sites
Jamez 2147483647 Report post Posted July 29, 2012 Our rear bushes seem OK. Maybe it was pressures...what do you run yours at hot? We are thinking of going A class this season too as the DOT tyre cost in B is too high and I'd like to try something differant. Keeping the rest of the car the same except for weight loss through lighter wheels and brakes and no ballast. Will be well off the pace of the fast A's but should be able to keep El Preso Foxy under control!! Wish September would bloody hurry up! I was running 30-32 hot, I found it didn't really matter to much as they were hard as nails. Quote Share this post Link to post Share on other sites
