Drfatz

Alright first I want to appologize for not having been around this forum in quite a while! I started graduate school awhile ago and it has been all consuming. At any rate just to give an update for those who might not know I have totally rebuilt this car from the ground up. ALL engine sensors are brand new as is the computer. She has new ignition gear from MSD as well as new ignition wires. She also has a wide band O2 sensor. I have run all new silicon vacuum lines as well as a nice new HKS pull type BOV. She has a high pressure fuel pump with AN-6 lines running into RC racing injectors. The primary injectors are the stock size where as the secondary injectors are larger (can't remember how big at the moment). She has a GT3071R turbo with a 3" turbo back exhaust. John at WC custom wrote a memcal for me to run about 19 psi of boost. She also had the head totally taken apart, multi angle valve job done and everything adjusted back to spec. Needless to say she is quite a quick machine! On to the problem. She was running fantastic the other day when I took her up to Thunderhill raceway here in California. I ran her for 5 20 minute sessions on 100 Octane (non leaded) race fuel. Everything was going fine and dandy until the last session about 2/3 of the way through I heard a strange pop sound from the engine and noticed she wasn't running quite right, but nothing was majorly wrong so I finished my last few laps and pulled her in. I noticed when I pulled into the paddock that she wasn't a happy camper and seemed to be running on 3 cylinders. Well I had no choice and had to drive her home and noticed that she was running very poorly and making strange "huffing" noises from the engine. I got her home and took one look at the exhaust tips and noticed she had been running very lean. Usually there is some black soot around the tips because she tends to run rich however, this time they were light brown. So I got to work. I checked the valve timing just to make sure, and it is perfect. I then checked all vacuum hoses and they are just fine. I then pulled the plugs and noticed that the #2 plug was dark black and wet indicating to me that #2 is running very rich/not properly burning. All of the other plugs showed singes of a lean condition and were light brown. I ran the car while reading the wideband O2 sensor and she had a tendency to oscillate between very lean and 14 AFR. I originally thought maybe it was an ignition module failure, but since there is one coil for two plugs I would think two cylinders would fail. Besides the modules are brand new from MSD. I am hoping it is just a bad plug, but fear I may have burned a valve. I posted pictures of the plugs below. Any suggestions would be greatly appreciated!

Just curious if I am going to be the only Esprit at LOG this year!

Wow some people have done some really wild stuff with Megasquirt. Thanks guys! I think this is the way I am going to go. Hey Mark, did you do away with the secondary injectors and just run 650cc primaries with the DTA? I assume with the more advances fuel system you can run much larger primary injectors without having idle problems.

I am going to give it a shot :-) Now I just need to figure out how to deal with the crank sensor and also where to get the GM connectors that plug into the ECM

I did a search and some people have kicked around the idea of getting rid of the GM ECM and installing a Megasquirt system. Well I am thinking of venturing down that road as I have heavily modified my car and can't seem to get the injection system to corporate. The biggest problem with the GM unit is tuning it. From my knowledge the only people that have hacked the GM ECM are John from WC Engineering, Marcus, and Andy Whittaker. The problem is John is extremely busy and far away from me Marcus is REALLY far away as is Andy. I have gone through a few chips from John and the car runs pretty well but its those limitations of the GM unit that are just annoying. I need to be able to tune the car myself live so I have decided to scrap the GM system and go for a new stand alone. Has anyone delt with the Megasquirt systems before? I really like the idea of the open source DIY system and its only around $200!!! :-) At that price mine as well try it and if it doesn't work I can always put the GM system back in :-)

Just an update. I took the S4s flywheel to an automotive machine shop and had them re-grind the flywheel back to the original lotus spec with the step and all. Before I had it reground I analyzed it with the machinist and we concluded that the PO had machined it improperly reducing the step and causing all of the slipping that I was noticing. Looks like I am going to get a standard S4s clutch seeing as I now have a good condition S4s flywheel and try and return the +35% upgrade to Marcus. I will try and take some pictures of the clutch replacement and post them. B)

Thanks Travis! Do you happen to know what the proper step height is for the S4s flywheel? It appears I am going to have to get the flywheel ground and I want to make sure it is 100% within spec. I spoke to Jeff at JAE and he firmly believes the S4s clutch should be able to withstand the amount of power I am producing. The reason for why mine was slipped is possibly becuase the flywheel was machined improperly by the PO or maybe I had not torqued the pressure plate down enough. The plan now is to fit up the standard S4s flywheel with a new S4s pressure plate and clutch.

I am not entirely sure what you mean Travis concerning the pressure plate lip however, there was no sign of grease or oil on the clutch when I removed it. I should also mention that when I stripped the engine and reinstalled the clutch many months ago I put on latex gloves and used a oil/grease solvent on the clutch setup to ensure it would be clean. As for crank HP, although I have not dynoed it yet, this car should be putting out more then 400 bhp :-P Finally, I am considering having the flywheel machined to accept the standard SE setup, but I am also going to check how much a custom clutch cost. Does anyone know what car the S4s clutch came from? I pulled off the pressure plate and clutch which both say Valeo on it, but of course they don't have anything stating they supplied a clutch to the S4s...So if anyone knows what car they stole the S4s clutch from it would be a HUGE help!

Bad news....I pulled off the gear box and found out that my car was equipped with an S4s clutch from the PO This means that even with the upgraded S4s clutch, she still couldn't handle the power. When I had the engine out of the car initially I inspected the clutch/flywheel and it looked like it was in like new condition so I didn't think anything of it. I had no idea that it was an S4s clutch at the time. I know it is an S4s clutch now because I just got a +35% (SE) clutch in from Marcus and found out that the bolt pattern for the new pressure plate dose not match the one on my car. Also I had heard from the garage that worked on this car before I picked it up from an insurance auction that they "thought" they had installed a "lighter" flywheel with an upgraded clutch. So now I have a bit of a problem. Should I go through the hassle of buying an SE flywheel so I can fit up the +35% clutch from Marcus or should I go have have a custom high output clutch made over here in the states? What do you guys think? Cheers, Graham

Wow Artie that looks fantastic! I should have powder coated mine when it was all apart, I just went for a wrinkle finish paint. P.S. Are you going to LOG this year?

At first I figured it was wheel slip since I still have an open dif, but then I was pulling onto the highway and gave it the beans from about 40 mph to about 80mph and the clutch was slipping like crazy :-( I actually haven't had a problem with tires breaking loose (other then in wet conditions) yet. I am running Yokohama ADVAN Neova AD07 tires mounted on V8 rims and they are fantastic!

My biggest problem now is my clutch is slipping big time when I get on the power since I have upgraded my engine a bit. I have adjusted the slave cylinder such that there is no preload on the clutch at all and its still slipping. I hear (perhaps Artie can chime in here) from the garage that worked on the car before I got it that it has an upgraded clutch in it. I just purchased a +35% clutch from Marcus and I really hope that doesn't slip because if so I will have to get a custom one made which is going to cost $$$$$.

Thanks for all the quick responses! So I guess the best bolt on option is the upgraded "+35%" clutch kits?

I am curious what is the strongest (highest torque spec) clutch you can buy for an Esprit. I have heard people claim that the S4s clutch is all you ever need, but you have to change the flywheel. How does the S4s clutch compare to the +35% torque clutch kits I see from PUK and Ramspott & Brandt?

Fantastic! Thanks Dan. I contacted the guys at Tuner C.A.T.S who were very receptive of the idea creating an ECM definition file for the Esprit. Now I just need to get the necessary hardware for chip tuning.