Half-Life | '91 DS 318iS Slicktop | Track & Weekend Warrior

[Digitalwave]

BMW Style 4 from an E38 16x8 ET23. Tires are 225/45-16. All info on the car is on the spec sheet in the first post/page 1.

[AWDBOB]

Love this car. Curious about 2.5 things:

1) do you ever get nervous running the Febi rockers with that cam?

2) how does your car feel down low with said cam on a 2.5?

2.5) do you think upping your compression helped significantly in supporting said cam?

[Digitalwave]

Love this car. Curious about 2.5 things:

1) do you ever get nervous running the Febi rockers with that cam?

2) how does your car feel down low with said cam on a 2.5?

2.5) do you think upping your compression helped significantly in supporting said cam?

Thanks! I'm not expert and I did not build this motor (bought it used), but here are my thoughts about your questions:

1) I am always a little weary of ANY M20 rockers, but I have never broken one in over 10 years of owning E30's. I keep my rev limit fairly conservative and try not to abuse it.

2) It's still quick below the cam comes on (around 4,600 RPM). But my car weights 2,400lbs and I'm running a 4.10 diff. With a 3.73 and a full weight street car, it might seem slightly lacking down low, but I would bet it's still faster than a stock M20 below the curve. It just has a more noticeable transition into the power band.

2.5) I think the compression did, but more displacement would have helped more. This is arguably too much cam for a 2.5L. I'm still making a lot of power right by the redline.

In summary, I wouldn't run this cam on a street car, but for my purposes I quite enjoy it. The sounds it makes are heavenly, too.

[Digitalwave]

Well, thankfully I think I found the issue with the car misfiring and fouling plugs. My MAP sensor had gone bad, and was reading very erratically. Replaced it with a new Delphi unit, along with the brand new 24 lb/hr injectors, and the car is running well again. Now just to finish up the tune!

Had to change the weatherpack connector for the MAP sensor, mine didn't have the right notches in it for the GM style connector.





Where I previously mounted the MAP sensor was too difficult to take it in and out, so I made this little bracket out of 90* aluminum. Came out great!







The MAP sensor is now properly mounted upside down (so no residual oil in the line or anything like that can foul the sensor element):





Picked up a sandblasting cabinet. Nice to have in the shop! I cleaned up my ground post, it was pretty nasty. The one on the left is the one that came off the car, the right is now like-new after glass bead blasting.





Here it is installed, I used dielectric grease after scrubbing each connected with a brillo pad to clean them up.





New Bosch Gen III 24# injectors installed. I had to replace my fuel rail as well. I didn't realize it before, but it was bent! Someone must have pried the hell out of it trying to remove it at some point.





Installed a new VC gasket. Mine was new, but the rubber textured type, and it was leaking. I think these ones with the bead around them are less leak prone. We will see.





Got a brake light switch mounted on the clutch pedal for launch control activation. I am not sure it is going to work well in this spot. The switch disengages too easily. In my testing, while it worked, if you leave your foot on the pedal with ANY pressure at all, it will switch and trigger the lower rev limiter again. I think I am going to have to change it to a switch at the bottom of the travel, instead of at the top. I'll have to do more testing. Not entirely sure how helpful this will be in reality, and may scrap it entirely.





Last but not least, here is the tentative spot for the tablet gauge cluster. It's just big enough to see fully through the steering wheel, and I am going to retain my shift light because it works better than any alerts you can set up in the cluster.

[ak-]

I want to move my switch to the clutch pedal for no-lift shifting, see eager to see what works for you!

[Digitalwave]

I feel like I have nothing to add to the thread, although a lot of has happened in the last few weeks.

What I thought would be a quick and easy process to switch over to Megasquirt has been anything but. Megasquirt has unmasked a lot of "little" issues with my motor. For instance, the bad CPS sensor as noted before. But, there have still been some little things popping up here and there, some we are still sorting through. A few vacuum leaks were discovered. I also moved the MAP sensor over to by the fuse box as it was getting really toasting underneath the intake manifold where I had mounted it before. It's not as hidden now, but it keeps it cool, and hopefully reading accurately at all operating temps.

In searching for vacuum leaks I found the lines on my intake manifold nipples were leaking. They got zip tied. Redid the PCV lines and put hose clamps on every juncture. Put hose clamps on the ICV elbow as well, just in case.

We "finished up" the tune and I did a track day last week that went well. The tune needs a little tweaking at idle still (which has surprisingly been the hardest thing to tune). We finished up the ignition and WOT fuel map on the same dyno I did my base line run on.

Compared to Motrnic we picked up a good 10-15hp across the powerband. Peak went up about 5whp.


I got the tablet dash mounted pretty cleanly. I tried velcro first which was a major fail (not nearly strong or stable enough). So I used angle aluminum to bend a bracket, mounted it under the cluster, and then used 3M double sided tape to secure the tablet. It's very, very strong and stable as it's mounted. Even track tested now!




















Random picture I found from the last Cars & Coffee:




Until next time...

[AWDBOB]

Those numbers are fantastic! Shows what a well sorted M20 can do. I wonder how much the cam and compression is helping scoot you along. I was planning MS for my simple M20 build, but ended up going with a chip instead. You don't have any fancy head work do you other than the springs and 284?

How does the car feel overall with MS vs having the AFM in there?

[wworm]

Style 4's are my favorite OEM wheels. Bummed to see that they dont even clear stock e30 m3 brakes without a spacer. Do you have any idea how much more do they stick out than stock e30 brakes? I know the the m3 rotor is 3mm thicker than the non-m rotor so theres at least that

[Digitalwave]

Those numbers are fantastic! Shows what a well sorted M20 can do. I wonder how much the cam and compression is helping scoot you along. I was planning MS for my simple M20 build, but ended up going with a chip instead. You don't have any fancy head work do you other than the springs and 284?

How does the car feel overall with MS vs having the AFM in there?

Thanks! Since it is stock displacement, it is really the cam and compression making the numbers. The other mods (injectors, exhaust) are more standard and probably not as responsible for the power level. The car still made a peak number of 195whp with the AFM/Motronic (and it was pretty lean, too).

The response is great, especially with the 8lb flywheel and 4.10 diff. It is slightly faster out of the corners and down the back straight than my friends FRS track car that has bolt ons and runs E85.

Style 4's are my favorite OEM wheels. Bummed to see that they dont even clear stock e30 m3 brakes without a spacer. Do you have any idea how much more do they stick out than stock e30 brakes? I know the the m3 rotor is 3mm thicker than the non-m rotor so theres at least that

The Style 4's clear the caliper, it's the anti-rattle clip that hits the bulky hub area of the wheel.

[wworm]

Good to know. From what I can tell its not a big difference. I'll have to do some more digging

[e30 gangsta]

Love everything you've done with this build TJ. Keep up the good work.

[digger]

Great results though It looks like you have a slight ignition issue based on the plots the output looks noisy almost

[vtechnik]

Soooooo much want.

[Digitalwave]

Love everything you've done with this build TJ. Keep up the good work.

Thanks "s13 gangsta" :D:p

Great results though It looks like you have a slight ignition issue based on the plots the output looks noisy almost

Could be (I never rule anything out with this car anymore, lol). All ignition stuff has less than 2k miles (coil, wires, cap and rotor, plugs, CPS). I am going to put a new cap and rotor on just in case, and try NGK plugs (stock or one step colder). I think the jitters are something to do with the dyno though. The AFR graph was doing the same with their LC-1 tail pipe sniffer, even though both widebands on my car were showing nice, smooth, and even. Some of the other charts from cars they've dyno'd looked the same.

Soooooo much want.

Thanks man!

[digger]

could be a issue with the machine its just strange that it happens at topend. i doubt it is the cap or rotor. id more look at the clearance between CPS and wheel MS (if not already i haven't read entire thread) is notorious for being sensitive to it