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

[Digitalwave]

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

That's awesome. I had come across some links to Gustave's old web site that were dead. I didn't know the site had been re-hosted, and furthermore even cooler that it's on my old e30sport.net domain!

That is going to be a great resource to read through again.

It looks like by the front edge of the radiator, you mean the further to the front of the car, yes? Not the back edge closest to the engine.

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?!

On the exterior of the hood, the high pressure is at the back by the cowl. However, we want to vent the high pressure under the hood (after the radiator) to the low pressure behind the nose. I know very little about aerodynamics, but I don't think it is effective to put the vents at the back by the cowl.

[mjweimer]

That's awesome. I had come across some links to Gustave's old web site that were dead. I didn't know the site had been re-hosted, and furthermore even cooler that it's on my old e30sport.net domain!

That is going to be a great resource to read through again.

It looks like by the front edge of the radiator, you mean the further to the front of the car, yes? Not the back edge closest to the engine.

Yes further to the front of the car. Front edge of the opening would be at the front edge of the radiator. I think this places the "open" portions of the vent at the outlet of the radiator - but it would be dependent on the actual design of the vent being used.

Gustave did a lot of cool work and it was great that he shared his knowledge. There are some pics of my former E30 M3 intake snorkle parts on the site.


MJ

[paynemw]

On the exterior of the hood, the high pressure is at the back by the cowl. However, we want to vent the high pressure under the hood (after the radiator) to the low pressure behind the nose. I know very little about aerodynamics, but I don't think it is effective to put the vents at the back by the cowl.

I agree, I wasn't thinking through the problem set clearly. I put that project on the back burner and stopped thinking about it. Thanks for the clarity! High pressure at the cowl would prevent the air under the hood from exiting if the vents were at the rear of the hood!

[Digitalwave]

Update time!

If you recall, ever since installing my Megasquirt setup, I've been having rich idle issues when the engine bay is heat soaked. One last ditch effort I did was one step colder spark plugs. It seemed like I wouldn't NEED them... but that it wouldn't hurt trying. Surprisingly at my last track day, they might have done the trick! I say might, because we got rained out. But we got in one solid session with a pretty dry track, and I was still pushing the car hard. The idle was perfect pitting in after the session. Before, I would basically have to hold the car at part throttle to keep it from stalling out, it was idling so rich.

So that's good news. I will report on that again after the next track day in a couple of weeks. In other news, I have been working with Lawrence over at N15 Design (www.n15design.com) to develop a center hood vent specifically for E30s. The design has been finalized, and they are being cut soon. We spent several weeks taking measurements [from my OEM hood and engine bay]. I'm really happy with how the design came out.

The center vent is about 8" long, a good compromise for 6 cylinder engine bays. It will feature a leading edge gurney flap to kick up the air, and the last slat is recessed so the air can settle back down on the hood. Each individual slat has the same natural arch/curve to it as the hood does. So if you look at it from the nose of the car, the far edges of the slats will not stick up higher than the center does. Little details like this make it very nice! They will be for sale on his site soon for anybody interested.

I will also be installing one of his E36 side vents on the passenger side of my hood, where the headers are. I don't see any need to do the same on the driver's side, as my intake is closed off to the high beam delete. There isn't anything particularly hot on that side of the bay, and I know the center and pass. side vents will make a big difference.












This was the first mock up that included lines at 8", 10", and 12" long. With the coolant sensors, CPS, and injector Home close to the front of an M20, we decided 8" is the way to go.








And here is the final size and placement.










Here is some inspiration I drew from the new Corvette (first pic), and I believe an ATS-V I saw at Cars & Coffee.














Knowing I'd probably have at least some water intrusion up front in the near future, I trimmed up my distributor plastic shroud to reinstall. This was because I have a relocated coil, and I run the single wire up behind the pass. side headlights.











The next project I worked on was making sure my electrical system was up to snuff. I always thought my running voltage was fairly low, usually around 13.4v-13.5v, even after charging the battery. After talking to Greg at Bavarian Restoration, he made some great suggestions that I applied to my car.

The first was to replace all of the fuses in the fuse box with brand new fuses. I always thought it was cool having old school factory BMW fuses in there, but he explained that the corrosion and oxidation on them after 30+ years usually causes some voltage drops. That was a cheap, quick, and easy thing to do.

I then went through every ground and power connector in the bay, and cleaned them up with a scotch bright pad and contact cleaner.

Next up was the alternator. I installed new brushes, which was very quick and easy. I did not realize that the alternator grounded through the case and the mounting point. I had painted my mount when installing this engine. I am sure it was still grounding through the adjusting bracket, but at Greg's recommendation, I installed a dedicated ground cable from the back of the adjustment bolt down to the oil pan, at the same point that the main engine ground attaches.

I also installed one of Greg's mucho nice alternator power cable -- the thick one that runs from the alternator to the starter. Lastly, I cleaned up all the connections on the engine bay power distribution block. They were all pretty nasty.




















I then used my multimeter to measure voltages at various points: the Megasquirt board, the injectors, the coil, etc. to make sure they all read accurately (and that Megasquirt was "seeing" proper voltage).

The end result? The first E30 I've seen run at over 14v! I am not consistently getting 13.8-14.1v, which I am quite happy with. It's an original alternator and a battery that is about 5 years old to boot.

Next up I adjusted the fitment of the CF hood. It actually fits MUCH better now. I don't know how I biffed it so bad last time I mounted it up. The hood seal now seals much better, which I think will help with engine bay air extraction, especially once the vents are on. Lastly, I adjusted the rear latches/catches, so that they are tighter. On the track, this GREATLY reduced the cowl shake I was seeing at 120mph.











Some new goodies from Kooglewerks arrived. Hand made aluminum front splitter and rear duckbill spoiler. I am going to have both of them powdercoated black, then both will be mounted and braced with Longacre turnbuckle supports.








The paint under my rear iS lip spoiler was atrocious, and the new spoiler does not fully cover up the footprint from the stock spoiler (although it uses the same bolt holes). I decided to shoot that area with some black spray paint. It's nothing to write home about, but it looks MUCH better than it did, and doesn't stand out like a sore thumb anymore. Also, the stock holes were a little rusty, so I hit them with a wire wheel to clean them up before painting.















And here is the final result after several coats of satin black Rustoleum. It's far from perfect, but it looks so much better!








Got to do a track day this month with my friends Julian and Gerry, as well as Carlos from Condor Speed Shop (in the white M3). We had a good time, but ran cut the day short. I think I need some anti fog for my windscreen. No blower motor. Doh!








The next track day is on May 8th. In June I hope to bring the car up to Sebring (finally). I've got a short list of things to do before hitting the track again:

-- Powdercoat splitter, spoiler, hood vents (black)
-- Install the splitter, spoiler, and turnbuckle supports
-- Cut the hood and install the vents
-- Install thinner spring pads (or remove completely) in the rear. The car has too much rake
-- Bleed the brakes
-- Rotate the tires
-- Do a once over on the suspension, brakes, etc. for safety
-- Touch up the tune in cruise a little bit. There are a couple of minor lean spots in transitions.

[wworm]

this has become one of my favorite cars on this forum. Stoked for more progress

[Sh3rpak!ng]

this has become one of my favorite cars on this forum. Stoked for more progress

Me too! Looking forward to pictures of the hood vent

Sent from my SM-G920T using Tapatalk

[AWDBOB]

I still can't get over how much power this thing makes for only having pistons and a cam. I can't wait for you to get the ITBs on!

Great work as always-

[wworm]

SO looking forward to seeing ITB installation/tuning

[Digitalwave]

this has become one of my favorite cars on this forum. Stoked for more progress

Me too! Looking forward to pictures of the hood vent

Sent from my SM-G920T using Tapatalk

I still can't get over how much power this thing makes for only having pistons and a cam. I can't wait for you to get the ITBs on!

Great work as always-

Thanks all, I truly appreciate that! The car is a ton of fun. I wish I got to drive it more. Every project I take on seems to take a lot longer than planned, which has prevented me from doing a lot of track and autocross events I hoped to do. For that reason, I am pushing off the ITB's for a bit. I would like to think it's going to be a weekend project, but with the way things have been going for me on the car, it's likely to take 3 months to install and tune them! LOL

[2mAn]

Love this stuff. As far as trying to reduce heat soak as much as possible, I would look no further than ///M themselves.

bmw-m8-103 by 2mAn

bmw-m8-102 by 2mAn

bmw-m8-9 by 2mAn

The fact is that the air passing through the radiator has no business in the engine bay, so your vent is the perfect first step, but you will want to try and do two things

#1 Air coming from in front of the radiator should be directed and sealed off to get good flow INTO the radiator.
#2 The air that has passed through the radiator should be directed into the vent, and not the engine bay.

One thing Ive wondered is why people dont try to move the radiator further up, under the core support & away from the motor. With no A/C and plenty of space up front, you might want to look into this

I would still look at putting the vent on the driverside too, because the engine itself will generate heat and the vents on the side will help to get as much hot air out as possible.
Since you've sealed off the air going into and over the car, what are you doing about the air going under the car?

I'm loving this stuff, as this was what I was beginning to do with the Aluminum Monster towards the end. I'm not a fan of the duckbill style spoilers, but its a BIG improvement over the "spoiler" that the E30s came with stock.

In the words of Singer, "everything is important"

[Digitalwave]

The fact is that the air passing through the radiator has no business in the engine bay, so your vent is the perfect first step, but you will want to try and do two things

#1 Air coming from in front of the radiator should be directed and sealed off to get good flow INTO the radiator.
#2 The air that has passed through the radiator should be directed into the vent, and not the engine bay.

One thing Ive wondered is why people dont try to move the radiator further up, under the core support & away from the motor. With no A/C and plenty of space up front, you might want to look into this

I would still look at putting the vent on the driverside too, because the engine itself will generate heat and the vents on the side will help to get as much hot air out as possible.
Since you've sealed off the air going into and over the car, what are you doing about the air going under the car?

I'm loving this stuff, as this was what I was beginning to do with the Aluminum Monster towards the end. I'm not a fan of the duckbill style spoilers, but its a BIG improvement over the "spoiler" that the E30s came with stock.

In the words of Singer, "everything is important"

I find it fascinating as well, especially the aerodynamic aspect of the hood vents. I never even considered that until reading Gustave's articles. I just wanted to get the hot air from the radiator out of the bay!

I would say that aero is something I am not ready to fully dive into. What I am doing in the near term is kind of an introductory stop-gap. Long term, I would be interested in doing a FULL front under-tray, a full rear diffuser (including removing the spare tire well and cutting into the stock valance), and a chass-mounted wing. I don't think I will ever take it as extreme as Rocco did.

I will say I was shocked to know that the stock iS rear lip spoiler was functional, and I think the larger duckbill will help. But as Forrest Koogle mentioned, ANYTHING trunk mounted is hampered in downforce creation because of the squishy trunk seal and the play in the trunk latch.

One concern of mine is the effect of a full undertray in the front on air flow to the oil pan, since it is a primary method of cooling an M20. I do have a nice 19 row oil cooler, but even that has compromises. I mounted it low because I wanted as much air flow through the kidneys to the radiator. BUT, mounting it low means less clean air flow through the oil cooler. I have recently done more work to seal off and duct air flow into the oil cooler, which has noticeably helped. I still need to make a shroud for the top portion of it.

The spare tire well, trunk area, and rear valance looks like they're terrible for aerodynamics. I don't know how important the tranny tunnel/driveshaft area are.

Obviously balance is important with the car, so I hope I am not doing too many changes at once.

Onto the subject of the ducting behind the radiator, like the ATS-V, Corvette, and even the ///M car you posted above have: YES. I love that, and loved looking at all the GTLM cars at the Sebring 12 hour last month that all route their radiators like that. With only a max of about 6" between the radiator and an M20 (and a min of about 1/2" from my fan to the water pump!), I don't know if anything like that will ever be possible, but I want to explore it once the vents are in there.

One cool thing: Chase Bays just came out with a "tucked" radiator for E30s. The radiator itself is smaller in exterior dimension, but it is a dual-pass design with more fluid capacity. It would actually be an upgrade over my single pass Mishimoto I believe. I think it would open up a crucial 2-4" of space that could potentially be a game changer when it comes to building a shroud behind the radiator, ducting the air directly to the hood vent.

https://www.chasebays.com/collections/bmw-e30/products/chase-bays-tucked-aluminum-radiator-bmw-e30-e36-e46

[rzerob]

Finally. I have been waiting forever for chasebays to release this radiator setup. I am definitely planning to use it for my next swap.

It is a little disappointing to hear the itb's are on the back burner but understandable. You put a lot of time and effort into the car. Enjoy it. And when winter runs around you can consider the itb's at that time. Great job, I look forward to your updates.

[Jb325is]

Man I'm a little bit surprised at all of the cooling issues. My car runs very cool on track and I've never had any cooling issues at idle with a 16" SPAL fan. We ran in Savannah this weekend and had to keep taping up the grill because the car was running so cool. Interested to see the results with what you're working on, but a little puzzled that you're having so many problems.

Regarding the aero, I'm with you on that. There is a whole lot of driver development that should happen without aero and it really needs to be integrated as a system. I see so many track builds where people forego the whole learning how to drive part and move straight to trunk mounted wings, cut-off panels, and useless diffusers.

What are you planning on for defrost? I was thinking of doing a grid on our car, but haven't pulled the trigger on one yet

[Digitalwave]

Man I'm a little bit surprised at all of the cooling issues. My car runs very cool on track and I've never had any cooling issues at idle with a 16" SPAL fan. We ran in Savannah this weekend and had to keep taping up the grill because the car was running so cool. Interested to see the results with what you're working on, but a little puzzled that you're having so many problems.

Regarding the aero, I'm with you on that. There is a whole lot of driver development that should happen without aero and it really needs to be integrated as a system. I see so many track builds where people forego the whole learning how to drive part and move straight to trunk mounted wings, cut-off panels, and useless diffusers.

What are you planning on for defrost? I was thinking of doing a grid on our car, but haven't pulled the trigger on one yet

I hear you man. It really is/was a strange issue (issues?). My fluid temps were never an issue. I have a 16" SPAL puller fan and never go above one needle past 1/4 at idle. But the engine bay definitely gets quite hot. Who knows. It's been a baffling thing to sort out, but it's definitely improved a lot (especially with the colder plugs).

I know I have a long, long way to go as a driver, which is why I want to stick to small tinkering mods that I can do in between track days, and don't take the car out of commission for a while. Hell, I'm still running H&R Race springs and Bilsteins. I don't need a chassis mount wing yet, lol.

I haven't looked at all at defroster options. I truthfully didn't think I'd ever need one (although I left the rear one in, until I do lexan windows, at least). Let me know if you find any good solutions.

[mr.]

Mind me asking how you cleaned up the vacuum lines that lead to the (brake booster?) I think it is
Looking to do the same clean up with mine before I get it back on the road after some head work and general maintenance