91 318is; do I use Spec E30 it?

#1

So I want to get into this Spec E30 racing as you guys seem like a good bunch of people and it seems like a great enviroment to be able to build an affordable race car. Here’s my dilemma, I had three E30’s and was going to use the 325i but it went missing the other day and there are no leads and even if it does show up again I probably won’t use it.

So I have a 91 318is and am thinking of using it. However with the article in GRM that said "…even though 318is is legal, they are encouraging everyone to use the 325i…" and all the talk back and forth regarding the new rule changes and the ECM testing, I am not sure I should use it even though I’d really like to.

The other is a 87 325e, which I don’t want to bother with.

Now from what I know there are only two people that are going to race E30 here in So-Cal right now, so it probably won’t make a difference, but I don’t want to get the short end of the stick because I have a different car.

I am getting geared up to start my build right now and don’t want a monkey wrench tossed in while I’m in the middle or at the end of my build.

Thanks guys.

#2

I recommend finding and building a 325i, even if it takes more effort and/or money.

Carter

#3

Carter,

How come? I know the 318 would be handycapped by less HP but that doesn’t bother me since it has a lower weight and a higher diff with LSD.

So besides the HP factor, why is it recommended to go with the 325i? It is to keeping things as close as possible as far as the cars are concerned? If that is the case shouldn’t you just say that only 325i’s are allowed?

I don’t see the 325ix on the list, is it allowed.

Thanks for putting up with all my questions. This is a very different change of pace from other race cars I built, series that usually there are a lot less limiting rules.

#4

I would sell the 318 and find a 325i. I think you’ll be behind the curve with that car, and it’s too expensive to build it into a race car only to find out it’s a dud on the track and unsaleable when the time comes.
May seem like a hassle, but you’ll thank me/us later. :wink:

#5

Mike Mills has a rental 318is Spec E30 car in the SF bay region - so you could talk to him about relative performance of the cars. I think torque is the main issue. Bit of a catch 22 - if more of them were running we’d know if there needs to be an adjustment in weight or something else, but people don’t want to build them due to the known unknowns. :wink:

cheers,
bruce

#6

I’ve got one. The car will be fine. I’m not scared of running it against 325’s.

#7

badboypolar wrote:

[quote]Carter,

How come? I know the 318 would be handycapped by less HP but that doesn’t bother me since it has a lower weight and a higher diff with LSD.

So besides the HP factor, why is it recommended to go with the 325i? It is to keeping things as close as possible as far as the cars are concerned? If that is the case shouldn’t you just say that only 325i’s are allowed?

I don’t see the 325ix on the list, is it allowed.

Thanks for putting up with all my questions. This is a very different change of pace from other race cars I built, series that usually there are a lot less limiting rules.[/quote]

While we were discussing the welded diff rules, Mike mentioned that the 318is didn’t have an LSD, thus the locked diff in his car. But my recommendation comes from several factors. Despite Rob’s good-spirited confidence, there are some unknowns that I would prefer to avoid if I were building a car. If the car (or the driver) isn’t competitive, there will be some complaining like the familiar Chevy/Ford complaining in NASCAR. And yes, we at Spec E30 want to avoid that too…but we’ll deal with it if we have to. And yes, the "everyone has the same car" thing is a factor for me personally. You can certainly build the 318 but I stand by my recommendation.

One more thing to think about, the Spec Miata is lighter and corners better than a 325i but is slower down the straights and I can drive away from them overall. Is the 318is going to be quicker down the straights than a Miata? Is it going to be more aerodynamically efficient? Is it going to brake deeper or corner faster? If not, it will be tough to stay with a well-driven 325i.

Regarding the 325ix, no it’s not legal for Spec E30 because it would cause even more issues with trying to get the cars close in performance.

And feel free to ask questions anytime.

Carter

#8

I have owned and driven both. Raced the 325. Tracked the 318is. Currently driving a 318i with a good street setup.

I am DYING to see a 318i/is race. I can’t wait to see how Rob does. I think the 318 will do fine (with some caveats).

BUT if it was my first RACE car on track I wouldn’t build one.

1> The 318is is a cult car. One in good shape that hasn’t been abused will be rare one day. They didn’t make that many and those that understand them know why they will always be a coveted (but slightly wacky) BMW cult car. So hack up a 325i four door…they are a dime a dozen. (you all know I love 4 doors!!)

2> The 318 is going to be a much more intense car to run fast laps in lap after lap. You are going to have to be way more precise, much better managing traffic and not give away ANY advantage. One simple mistake will hand the advantage to a 325.

3> I do think that it will be faster into and around the corners…simple physics…but as crappy a driver as I was… a simple defensive line KILLS that advantage most of the time…and the big engine will out run the 318 in a drag race out of the corner.

4> I think if you are a "larger" guy…it may be tough to make weight. There simply isn’t that much to take out of a 318. Mine is light as it sits from the factory. They probably won’t weigh THAT much different once the 325 and 318 are stripped out. (Diff and engine are the two big items). If you can’t make minimum weight with your fat butt in the car you have LOST the most important point of the 318. Rob…what is your weighing empty in race trim???

That being said…

I think the 318i/is is an absolutely brilliant track day car. Lap times are irrelevant and the same low HP /light weight will make you a better driver as you can’t hide behind HP to make the car work.

Some of the most fun I ever had was a 318is in the wet. Just brilliant.

It really is like a different car.

#9

An option might be to part with both the 318 and the 325e and put the dollars towards a 325i or iS and start the build on solid footing. At least with a 325iS you don’t need to source an LSD, although I think it’s probably not difficult. I would be concerned about the future competitiveness and saleability of the 318 built for SE30 - I’m sure there is plenty of demand for a clean streeter tho. Good luck with your decision.

-AJ

#10

Few interesting tidbits for those interested in the 318is.

I think 130-135whp will be relatively easy.

1,2,3, gear are lower than the 325i. 4.10 final drives are stock so you are using 3rd, 4th, 5th on every track. My car did 117 down the straights at VIR with no bumpers and no aero work on the front end and no draft. The fastest speed I’ve seen or heard of in a 325i is 122 with James Clay at the wheel. It gets off the corners in 3rd gear very well, I don’t use 2nd really ever.

Mine was a driveable 1926 pounds, full body without a passenger seat, bumpers and exhaust. Corner weights were dead even. With me in my stripped car, it has reward weight bias. The 100 pounds minimum ballast will be tough for us. My full of gas street car with full interior, spare, and tools was 2450 pounds at Summit Point.(PS, AC, Radio were stripped) At legal weight I’ve calculated about 54% reward bias race ready. Rearward weight bias helps HUGELY on standing starts and braking. The torque gained by running a M20 should be negated on a start by that alone. I think a 325 is about 55-56% forward bias.

318is will take very little chassis prep as there is 1/10th the sound deadening. Adjustable Cams are stock so you can move the powerband a bit more to where you want it.

Limited Slips are available, and were an option on 318is cars (I reccomend finding one from a 85 318). I expect to go through one a season because they aren’t strong and the discs wear quickly. 318is Diffs are very small and light, this with the light gearbox only has about 14-15% driveline loss. Figure 18% on that 325.

Clutch and Flywheels are lighter because they are only 215mm.

The front end sits kinda high compared to a 325 because of the light engine and non adjustable suspension. This kinda sucks but the roll center is a bit better I guess. I guess it’s a tradeoff for having better balance.

You don’t break rocker arms when you don’t have them. Just wire on the oil pump nut, and I’m looking into making a baffle and crank scraper.

With the big gas tank you will be unstopable at long enduros, I get about 12-13mpg on track.

We’ll see how it shakes out but I really don’t see why the car won’t be competative at shorter tracks. I think it’ll get beat at VIR or Sebring places where you have to stay on the gas for awhile. No reason anybody shouldn’t run dead last every weekend though if they can drive ok. I’m a fair driver and it will take me a bit to learn road racing, but I’ve got a guy sitting behind me that loves driving my car. I’m sure he can show the true potential for us rather quickly.

#11

Hi Rob,
so from 1926lbs (wow!), how will you get up to race weight with only 100lbs of ballast?
cheers,
bruce

#12

I having an anti gravity machine installed. :woohoo: