Hi everyone. Ex SCCA Street Mod racer here.

[megatron]

Hi everyone, just wanted to introduce myself to this wonderful forum.

I'm an ex-SCCA Solo Street Modified racer, and thinking about doing it again with a ti.

I've been lurking on the forum for a few weeks, gathering info while considering whether to get a ti. I ended up buying a 96 last weekend that's too clean to do what needs to be done to it for Solo racing, so that one is going to be my dad's commuter. It is pretty clean and has the LSD option, which was a nice bonus.



So I'm looking for a cleanish (at least straight) 95 to build. The OBD1 will give me more options for making it so I can still register it for street use after building it up.

The previous car I built was a 99 M3. I did an aluminum block, aluminum doors, carbon fiber and titanium everything, 315 tires, some flares I made and a Eurosport Twinscrew into it. I raced it with my friend Scott Fraser at the 2006 SCCA Nationals in Street Modified and with minimal seat time, we we came up second fastest behind Bob Tunnell's Twinscrew 95 M3. I sat out of Solo for a few years for graduate school and to start and run a business in Asia, but I'm now back in the USA and I'm thinking of maybe trying again with a ti and a different approach.

Car at 2006 Nationals:



I hope be able to contribute to the forum a tiny fraction of what I've already gotten from it. Thank you!

[BlackBMWs]

Hi Megatron! Welcome and thanks for the pics!

[BimmerBum]

Welcome! I love the M3. You sure you will not find the ti boring after owning that M3?

[megatron]

I'm hoping I can make an even faster ti.

[COOPERDB]

WELCOME ---


Did you do the rear fenders on your M3 -

Is there a link ---

[megatron]

Yes, I made them. Will likely make something also for the ti if it needs it, but taking a different approach that may not need tires as big as 315s to be fast.

[MINIz guy]

Good luck making the ti competitive!

I was talking to a SCCA member with a S52 swapped ti and M-roadster rear end. He was only able to run 245's under the stock fenders and says the rear suspension design isn't good enough compared to other SM cars. It may be a long and expensive road to get a ti to be competitive in SM.

[jca]

Welcome to the site. Please keep us posted and put up some pics of any ti build that you do. Cheers, John

[megatron]

Originally Posted by MINIz guy

Good luck making the ti competitive!

I was talking to a SCCA member with a S52 swapped ti and M-roadster rear end. He was only able to run 245's under the stock fenders and says the rear suspension design isn't good enough compared to other SM cars. It may be a long and expensive road to get a ti to be competitive in SM.

It's a long and expensive road to get any car competitive in SM.

I have the blueprint for my old car, so if it's not working out, I can always just replicate it. But it wouldn't be as fun as trying something new. I've always been a fan of the ti's hot hatch style, and I think it can have a real good shot with the right approach.

Three things that I think are noteworthy:
1) The rules have polarized the potential builds into add power (and tire) versus add lightness
2) The ti is at a sweet spot weight and component wise where I think it could do very well with the later approach
3) The SM rules only state they you have to use the stock suspension-to-chassis attachment points and leaves the entire rest of the suspension wide open. I've yet to see this fully exploited.

[megatron]

I managed to find a clean 95 318ti with 126k documented miles and got it for a great price. It looks nearly identical to the other ti I got (the one I posted above), but without the body color bumpers and side skirts. This will be the car I will build.

I'm going to go with a "add lightness" approach on this build, and I'm considering whether to try building up a high revving M42, or to just stick the aluminum block 6 I have in there. I'm leaning towards trying the M42 because the minimum weight rules for Street Modified favor smaller displacement, and because M42s are widely available in junkyards for bargain basement prices whereas the M52B28 aluminum block is a bit of a unicorn these days. Thoughts?

[BimmerBum]

There is good power to be had from a built M42. I think the bottle neck in the M42 is the intake manifold. Maybe a different intake manifold would be needed to extract competitive power.

The M42 is cheap but getting power out of it is not, this factor would close the gap in cost between the M42 and alu block M52 quickly.

You are going up a liter in displacement with the M52, that is a 200 lbs weight penalty correct?

Interestingly, I just pulled my aluminum block 2.8 out of mothballs.

https://www.facebook.com/BimmerBum/p...type=1&theater

Originally Posted by megatron

I managed to find a clean 95 318ti with 126k documented miles and got it for a great price. It looks nearly identical to the other ti I got (the one I posted above), but without the body color bumpers and side skirts. This will be the car I will build.

I'm going to go with a "add lightness" approach on this build, and I'm considering whether to try building up a high revving M42, or to just stick the aluminum block 6 I have in there. I'm leaning towards trying the M42 because the minimum weight rules for Street Modified favor smaller displacement, and because M42s are widely available in junkyards for bargain basement prices whereas the M52B28 aluminum block is a bit of a unicorn these days. Thoughts?

[BimmerBum]

Are the rules for SM still:

1800 lbs plus 200lbs per liter. If you are not running tires over 275 then another 200lbs can be removed?

1.9 with 275s square would have to weigh 2000# without driver.
2.8 with 275's square would have to weigh 2200# without driver.

[megatron]

Yup, those are the rules. The other factor is +1.4L for Forced Induction.

I'm going to get my 95 ti on some scales soon and estimate based on my M3 build where I think I can get the weight, factoring in the various engine options, and go from there.

Running some scenarios, I don't think the M42/44 can make enough power NA with an M42/44 head still on it. Fortunately, Street Modified only stipulates the origin of the block. I'm also worried about being able to get it down to the minimum weight for a 1.9L NA build, but we'll see once I actually get the car on a scale to see where I'm starting.

Really cool that you're putting your aluminum 2.8 in your ti. In my M3 build, my aluminum 2.8 started out as an NA engine for a year while I waited for the Eurosport Twinscrew to get arrive to me. It made 225whp with just the S52 head (really just cams and valve springs difference), bolt-ons, and off-the-shelf Dinan Stage 5 software, so a more aggressive build could make a bit more power NA.

[BimmerBum]

You would have to get pretty creative to make weight with an NA M42/44 but it does not look like creativity is an issue for you. What head are you considering? S14? I'm not even sure that fits.

My ti currently has an S50 with 24# injectors, 3.5 maf, intake and proper chip. I will be transferring all that over to the M52 along with shorty headers, S50 cams and pulleys. Based on reports from folks that have done similar builds (like you) I think 230-235 wheel is realistic.

Originally Posted by megatron

Running some scenarios, I don't think the M42/44 can make enough power NA with an M42/44 head still on it. Fortunately, Street Modified only stipulates the origin of the block. I'm also worried about being able to get it down to the minimum weight for a 1.9L NA build, but we'll see once I actually get the car on a scale to see where I'm starting.

Really cool that you're putting your aluminum 2.8 in your ti. In my M3 build, my aluminum 2.8 started out as an NA engine for a year while I waited for the Eurosport Twinscrew to get arrive to me. It made 225hp with just the S52 head (really just cams and valve springs difference), bolt-ons, and off-the-shelf Dinan Stage 5 software, so a more aggressive build could make a bit more power NA.

[megatron]

Ideally an S42, but I can't imagine the cost would make any sense. Given what's happening with E30 M3 pricing, the S14 is probably not a good choice either. So maybe something based off a (gasp) Honda head or motorcycle-style head. Still not sure if I want to pursue it, but it would be a good learning exercise to try and M42s are really cheap and available so blowing up a few along the way wouldn't be too bad and perhaps even the optimal approach to find the limits of the engine.

Yah 230whp should be doable with the aluminum block and bolt ons. The headers I had on mine when it did 225whp NA were big honking AA headers in preparation for the Twinscrew and the NA torque was pretty bad. The shorties you have will be much better.

One thing you give up on an S50 vs aluminum M52B28 block is compression, at 10.2:1 versus 10.5:1 for the S50/52. I had the deck on mine shaved to 10.33:1, but it was still giving up a bit. Your engine looks clean, so I take it you're not gonna crack it open, but if you do, this is a place to get some incremental gains.