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

[Digitalwave]

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

Ahh, the dreaded VR sync issues! I had those big time when I first installed MS. The car wouldn't rev past 4,800 RPM. I tried different resistors on the VR signal first, but it wasn't fixed until I installed a brand new OEM metal CPS. It is set to the proper air gap. Spec is 1.0mm +/- 0.2 I believe, and mine is set to .90mm.

Last time I checked, my VR signal shows very clean all the way through redline via the tooth logger, but I can check again next time I drive the car just in case. I know that I haven't had any "sync loss" at all since fixing the CPS, since I have the counter on my Tuner Studio dash as well as my tablet gauge cluster in the car. Thanks for the ideas!

[varg]

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

The dyno readout being so noisy and weird looking isn't due to the car itself, it's down to the dyno setup or the operator. I don't know how to run the thing so I don't know what caused it, but I've seen plots like that smoothed out with a couple of clicks before. The car pulls cleanly to redline and never loses sync.

[2mAn]

you should hit up level motorsport (hes on instagram and has a dead build here). he has a lot of cool stuff he made and is now parting out his racecar. some of the stuff could really help you.

I love that this is still a 2.5L M20 and makes solid power

[Digitalwave]

Not a ton to update on the car. I spent a lot of time working on the idle on Megasquirt. I am still having an issue with it idling rich after coming off the track. I have a separate thread for that here if anyone is interested.

I have done a couple of track days, which were a blast. Finally got down to a new personal best time at PBIR (1:34.90).

It's pretty hard to "read" spark plugs, but my stock Bosch Super's were looking pretty baked for being brand new. I switched to one step colder NGK's. Didn't notice any difference, but I am going to run them for a bit and see how they look.





I cleaned all the contacts and reseated the pins on my ICV wiring. Pulling back the rubber gasket, I was surprised there was moisture or oil in there. Weird.





I remembered by chance that when I originally lengthened the wiring for my tucked ignition coil, I did not continue using shielded wiring on the wire from the ECU to the coil. I wanted to re-do that, so I removed as much as I could of the stock shielded wire from my spare engine harness.





This is how I had originally extended it, soldered with normal copper wire.





Made brand new eyelets for the coil using the OEM method, both crimped and soldered. The original eyelets were corroded.





First step is to join the shielding, being extra careful that none of the grounded shielding strands mix with the power cable.





Then join the power cable separately, wrap in foil, electrical tape the whole thing. Then I finished the rest of the harness with TESA cloth tape.





I bought a new SI board, as mine was causing several issues on the cluster. Sure enough, the one I pulled out had some bad traces from somebody using the long trim screws in the wrong place. The board from ProgRama appeared to be brand new, not a remanufactured original board. It was very nice, easy to install, and worked perfectly.





A new project I've started on is cleaning up all my grounds in the car. I also replaced all of the factory ~30 year old fuses with brand new fuses. I am trying to get the voltage system up to snuff. Next up is a new alternator cable and a dedicated ground cable for the alternator from Bavarian Restoration. I didn't realize that the alternator grounds through it's mount, and I spray painted it, LOL. I am going to run a ground cable from the case to the oil pan, and replace the brushes/voltage regulator on my alternator.

I've also been working on engine bay cooling. It gets quite hot on there, even with the ceramic coated headers. The first thing I did was tape up the gaps around the radiator with DEI aluminum tape. This stuff grips well and doesn't show any signs of loosening up yet.

On the track, I did not see any appreciable difference in temperatures, but it did not hurt. I also experimented with removing my hood seal on the track. You could tell the difference in wind noise at 100+ mph, and the wiper blades were getting pushed up, but again, no noticeable difference in temperatures.

I am thinking about drilling holes in my front bumper (a la Sherpaking) and core to get more flow to the radiator, and also considering adding a vent to the front-center of my hood (like Trent did back in the day).













And as usual, here are a couple parting shots of the car on the track:

[UNHCLL]

TJ -
Food for thought on under hood temps.
The E30 engine bay is by virtue of design, terrible at shedding heat.
Even with a large pusher fan, if you have a good intact hood gasket, and complete under-car shielding, the air "struggles" to escape the engine bay.

I've had multiple E30's that when using E3 hood gaskets, large radiators, full under-car cladding and a big pusher fan, cannot keep cool when not moving. The instant you pop the hood and allow air to escape the engine bay out the back, temps drop instantly.

Next time you're out driving on the street, watch your temp gauge. While driving a constant speed, release your hood. You'll likely see a near instantaneous drop in temp.

That is the benefit of the Gustav style hood vent that Trent used. It helps draw air out of the engine bay. I doubt you need to get more air into the engine bay/through the rad, you need to get more OUT of the engine bay.

[Digitalwave]

TJ -
Food for thought on under hood temps.
The E30 engine bay is by virtue of design, terrible at shedding heat.
Even with a large pusher fan, if you have a good intact hood gasket, and complete under-car shielding, the air "struggles" to escape the engine bay.

I've had multiple E30's that when using E3 hood gaskets, large radiators, full under-car cladding and a big pusher fan, cannot keep cool when not moving. The instant you pop the hood and allow air to escape the engine bay out the back, temps drop instantly.

Next time you're out driving on the street, watch your temp gauge. While driving a constant speed, release your hood. You'll likely see a near instantaneous drop in temp.

That is the benefit of the Gustav style hood vent that Trent used. It helps draw air out of the engine bay. I doubt you need to get more air into the engine bay/through the rad, you need to get more OUT of the engine bay.

Chris, thanks for the feedback. That's good to know. I have indeed tried the hood pop and it makes a huge difference. I do run the stock plastic under tray and my hood seals "okay" (the cf hood bows in the middle). It is good to know that the Gustav style vent is effective.

Just to be clear, you recommend a center vent, 6-12" behind the roundel? To me that seems like it would be the most effective for extracting air from the radiator. There is also the "GTR style" hood with the 2 vents on the side of the hood. That might be better for forced induction, but I don't see that working as well as a center vent for an NA car (especially since I have a headlight intake duct).

[2mAn]

The center vent is the way to go as the hot air that has passed through the radiator immediately can escape the engine bay.

[jeenyus]

can we post some pictures of these vents?

[Digitalwave]

Here is Trent's.








DTM Fiberwerkz "GTR" style hood:




Another one I saw on the forums:





Since my hood needs a new clear coat/gel coat anyways, and my friend has a spare center vent from a 3piece set he bought for his E46 (and only used the sides), I am going to cut my hood and do this soon.

[Digitalwave]

Just found some more of trent's car. It's hard to find info on his car since he deleted his account.

https://www.r3vlimited.com/board/showthread.php?p=4702522

[paynemw]

I actually went through this same problem when tracking my car, this is from my build thread bottom of page 4. I ended up buying a 2nd hood & trunk lid so I could do some cutting and make a track set:

So, the other day i was poking around the internets looking for research about aerodynamics and such as it applies to the e30 chassis. After realizing that the SPECE30 guys don't mess with it because they can't, I figured only a few people really look into it. Chump and lemon guys, and any HPDE or TT folks.

So, the first question I had was, where to do the choppin?! As a kid I never knew why the cowl induction hood worked so well, but this picture helps explain that. All of the pressure at the cowl plus probable low pressure under the hood sucked it right on in.

but I know that's probably not the most efficient way of doing business given that we don't have a V8 and we our airbox is way up front.

Another r3v member posted this picture that made me think about heat extraction AND encouraging air movement through the driver's side headlight area.


So when I saw suggestions, I thought about that this was probably the smartest application of science, but I might adjust it to just the driver's side and center.

Here's how he did it:

And underside of the hood:

And given this probably has a significant amount of money in it, I'll use this as confirmation that the center vents are proven:

And this is just science!

Now, what say you?! I tell you what, but I'm stoked to start choppin' on my hood and build some aero for the trunk lid.

[Digitalwave]

Thanks for sharing! That is helpful. Have you done any cutting yet?

Here are some more pictures of Ron Checca's car. The vents were made by a defunct company, Competition Concepts. It looks like DTM Fiberwerkz directly copied this hood with their "race center vent" version.








If I can't find a suitable vent to cut into my hood, I will probably just sell my CF hood and buy the DTM Fiberwerkz version with the center vent. Should be able to do so without a big $$ loss.

[Digitalwave]

Here's another one I found. Probably a bit too far back for an M20.

[mjweimer]

Link to Gustave's hood vent info:

http://e30sport.net/installs/installs-3/hood-vent/index.htm

I think the key to this mod is placing the front edge of the vent right right at the front edge of the radiator - as shown in one of the pics.



MJ

[paynemw]

Thanks for sharing! That is helpful. Have you done any cutting yet?

I haven't yet. I purchased an '87 325e for the hood & trunk for $80, sold off the good parts and roller. I'm going to put a huge duckbill type spoiler in the rear and chop up the hood. The intent is to do more research to see where the best location is. I have the OEM plastic under my 325iS, so my assumption is that up front where everyone else has the slits is ideal, however, the way the hood is designed, it doesn't allow them to be very wide, which is frustrating. I also noticed from Surface Pressure Distribution image, that the most pressure happens to be right at the cowl of the e30 hood, so is there any requirement for airflow back there after vents are placed behind the radiator?!

I also have an almost 100% airbox set up, just missing the tube between the rear headlight plastic to the airbox, so I want to ensure I have a ton of cold air passing through that area of the engine bay. But it will probably be a low pressure if I just opened up a huge path in the center of the engine bay, so I want to think about the negative affects if that happens.