Phloozy builds a TT car

[wootloops]

Originally Posted by Driven5

That's largely because the stock ('flat') ride rate distribution is overseer biased and gets a surprisingly large portion of its roll rate and natural understeer bias from the sway bar(s). As you increase the spring rates, the same sway bar(s) contribute a decreasing proportion of the roll rate. So if keeping the same f/r ('flat') ride ratio, as the spring rates rise, it transitions from a steady state understeer characteristic to a steady state oversteer characteristic. Once you reach your desired handling balance, any further increase in spring rate would require a proportional increase in sway bar rate. At dedicated track car spring rates you can get into some absurd front bar sizes to keep it balanced, so the most common alternative is to run proportionally higher front ('pitched' ride) spring rates at the expense of 'flat ride' characteristics.

At more street friendly rates, the 'flat' ride ratios should generally work better... Well, that's the fundamental theory at least. There are obviously many other factors that influence this as well.

Great explanation. Up until I read this I couldn't wrap my head around how much understeer came out of the stock F/R spring rate distribution, but that makes perfect sense.

I'm guessing the stock staggered tire setup plays a role as well.

[chris82]

Originally Posted by bbnks2

Seems odd someone like bimmerworld would recommend 800/1100 based purely on a "300lb/in split." That's just not how suspension works. 100/400 springs would be a 300lb split and actually be a pretty balanced setup since the rear spring rate is pretty much 1/3 as effective as it should be. 800/1100 is massively front biased. Bimmerworld races 328i's though so you'd think they have a pretty well sorted car to base things off of. Maybe their race cars have true rear coilovers? That would make 800/1100 much more neutral handling.

If I keep seeing 128i videos like this I am going to need to sell my 135i. I liked my NA 128i so much better on track. It actually like being at 6,000rpm+ lol and lifting a bit to change the cars balance didn't lose all your boost :/

1:29:9 at thunderbolt is faster than a spec e46. That's a damn fast lap.

I love the 128i on track, unfortunately passing can be tricky when people don't lift!

A lot of times they end up being very late passes way into the brake zone but I honestly stopped caring, I take them no matter how late and force the other car to take a terrible line in those maneuvers to try and teach them a lesson about not lifting for slower cars 😂

[Phloozy]

Originally Posted by chris82

I love the 128i on track, unfortunately passing can be tricky when people don't lift!

A lot of times they end up being very late passes way into the brake zone but I honestly stopped caring, I take them no matter how late and force the other car to take a terrible line in those maneuvers to try and teach them a lesson about not lifting for slower cars 😂

lol I almost want to get a banner that says "it's a 128!" Since no one ever lifts for me and i literally can't pass unless I'm already carrying speed. I think they think it's a 135 or they see bmw and assume it must have some power.

[Phloozy]

Making 245 Hoosiers fit is more difficult than I was hoping… purchased apex's new high offset 17x9 +52 witch they thought should fit with a 15mm spacer, turned out they still barely fit with a 20mm surprisingly there is no rubbing that I can see/feel inboard but I think I'll need to pull the fenders a bit too to be safe. I'll be sticking to 225s for now until I figure this out.

[spidertri]

I assume the 245 Hoosier on the 9" wheel fits within the NASA tire gauge? You are limited by the 266mm gauge?

[Phloozy]

Originally Posted by spidertri

I assume the 245 Hoosier on the 9" wheel fits within the NASA tire gauge? You are limited by the 266mm gauge?

Yeah that is my understanding.

[spidertri]

I was mainly interested in how much the 245 on a 9 filled out the gauge. Just to get an idea of how much spacer you need and what I should expect once my 255 RT660s get here. Tire rack says section width for the 245 hoosier is 10.3" and 255 RT660 is 10.4".


I found this on the NASA forum:

"I tested the 9" Arc-8 with the 245/40 x17 R7 with a date code of 2317, and it fit the 266mm tool by less than 1mm at 35 psi.

I'm a little concerned that there may be a significant variance between tires of different date codes of that specific model (although the later codes seem to be okay). So,

I suggest checking your specific tire. If it measures 275mm off the wheel, it is unlikely to pinch down to 266 by using a 9" wheel. If it is 270-271mm off the wheel, I would think it would fit."

[bbnks2]

Originally Posted by Phloozy

Making 245 Hoosiers fit is more difficult than I was hoping… purchased apex's new high offset 17x9 +52 witch they thought should fit with a 15mm spacer, turned out they still barely fit with a 20mm surprisingly there is no rubbing that I can see/feel inboard but I think I'll need to pull the fenders a bit too to be safe. I'll be sticking to 225s for now until I figure this out.

What end-links are those? i bought whiteline recently and they were way too long. The ones I have on my car now came with my coilovers and are all seized up from years of grime.

[Phloozy]

Originally Posted by bbnks2

What end-links are those? i bought whiteline recently and they were way too long. The ones I have on my car now came with my coilovers and are all seized up from years of grime.

Ground control. Good luck getting anything from them though

[spidertri]

Phloozy Do you think you might ever make the drive down to VIR? I'd love to see how your car compared to this dude who runs an E36 M3 down here in the SE region. Same build philosophies it seems, he's running aero and hoosiers, and it really seems like that is the way to go with TT5 cars.

[Phloozy]

Originally Posted by spidertri

Phloozy Do you think you might ever make the drive down to VIR? I'd love to see how your car compared to this dude who runs an E36 M3 down here in the SE region. Same build philosophies it seems, he's running aero and hoosiers, and it really seems like that is the way to go with TT5 cars.

Would love to. I am also really interested to see how the 128 keeps up with the m3 as they are pretty damn similar. Is definitely on my list for next year. You know the name? I know there is one m3 driver down there that is destroying records.

[spidertri]

Yeah, same guy, Jon Kozlow. I met him a couple years ago at CMP and he seemed like a nice guy, had no idea at the time how fast he was lol.

[Phloozy]

Sadly my camera was pointed down for my 1:14.5 lap lol but here is my 1:14.6 at NJMP Lightning last weekend with NASA NE

[Chris N]

Phloozy, I am tracking my daily 2011 128i M-package 6-speed slick top. Mods so far are: LSD, poly SFB, ECS sway bars, Bilstein shocks, BMW Performance springs. Next up is a full TC Kline racing suspension then half cage.

However, before the suspension I have got to fix the power loss midway through my sessions...hence my post. It seems to happen when I upshift after things are heated up (this occurred this past weekend at Mid-Ohio). I have been trying to code out the brake heat assumption nanny which is what I thought was causing the power loss.

I read early in your thread that adding the oil cooler corrected the issue. Please confirm. Can you also add a parts list or maybe private message me?

Here's the wife pushing it.

[Phloozy]

Originally Posted by Chris N

Phloozy, I am tracking my daily 2011 128i M-package 6-speed slick top. Mods so far are: LSD, poly SFB, ECS sway bars, Bilstein shocks, BMW Performance springs. Next up is a full TC Kline racing suspension then half cage.

However, before the suspension I have got to fix the power loss midway through my sessions...hence my post. It seems to happen when I upshift after things are heated up (this occurred this past weekend at Mid-Ohio. I have been trying to code out the brake heat assumption nanny which is what I thought was causing the power loss.

I read early in your thread that adding the oil cooler corrected the issue. Please confirm. Can you also add a parts list or maybe private message me?

Here's the wife pushing it.

Yup I had the same issue and oil cooler fixed it completely. I used the 135 thermostat but with an aftermarket cooler, one of these https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 and everything on this summit order.

[Chris N]

Thank you very much! I can't express how frustrating loosing power after getting a point by has been.

[Chris N]

Looks like you used 1 - 45° and 3 - 90° fittings, correct? Also, did you use simple hose clamps?

[Phloozy]

Originally Posted by Chris N

Looks like you used 1 - 45° and 3 - 90° fittings, correct? Also, did you use simple hose clamps?

yup, and i honestly forgot what clamps i got

[sholzer]

Awesome thread so far with lots of info. Just picked up a 128i that I'm planning to track and an oil cooler was one of the firsts on my list of to-dos and your parts list is a huge help!

[chris82]

Which diffsonline lsd do you have? Seems to be doing you well. How do you like it?

[Phloozy]

Couple updates and small changes. Last event at njmp my brakes were MISERABLE. Super inconstant and something felt wrong. When I got home I put it on the quick jack and saw I lost a rear caliper guide pin... Thankfully I noticed with enough time before my next event and I ordered the bimmerworld solid brass caliper slide pin bushings. GET THIS MOD! My brakes felt so good afterword.

I also trimmed my bumper/fender tab, swapped to longer wheels studs, and made 245/40/17 R7s fit on the new Apex wheels. Lastly I installed my carbon fiber hood and aero latches.

After all of that I head to Watkins Glen for the first time ever this Monday/Tuesday and the car performed better than ever. The track was a ton of fun and I was surprised how safe I felt even with all the walls. Pretty sure the TT5 track record is a mid 2:08, I had a few low 2:08s but kept hitting traffic My best lap ended up being a 2:09.0 which is pretty damn solid I think for a first outing.

That is probably the last event for the year for me. Next thing to do is get the car ready for a cage and get as much weight out of it as I can! Also looking into swapping in shorter gears next year so I will be researching that as well.

[tsk94]

Shorter gears as in, shorter final drive, or actually changing the trans gear ratios?

Also, I can almost guarantee you're losing time going that wide at the exit of T1 - something to keep in mind maybe.