Swap 1/4 Mile Thread

[justin_l_]

Well, if everyone had a 2.8 stroker ix they could sidestep at 6 grand and take off like a bat out of hell it probably would :p



Damn, that's pretty quick. Justin's was sort of a freak of nature though.

You're running a stock M50TU on r-comps? No chip or anything?

Seems like a lot of DOHC guys have a straight-up cone filter (hot air intake), I'm not sure how much hotter IATs are with that but I doubt it helps much. Justin's heat shield and probably the fact that he's running a really tall first gear (equivalent to a G260 and a 2.93 or 3.25 he said, didn't he?) and didn't have too many traction problems is probably partially to blame, but a 13.9 is a lot quicker than I'd expect to be, even with some WR and a chip.

I take that as a compliment . I have since sold that to somebody in mass and am currently building slammed hardtop vert with a holset hx35 powered nv m50. Should go like a raped ape. Looking for 350ish to the wheels. Wonder what type of time this is gunna be puttin down...;)

[rneedham1979]

Sir,

You are absolutley correct! Many believe the term R-compound helps standing start traction, this is often not the case with a roadrace tire like the RA1, Nitto RII, NT01 etc... I have tried them all(E39 M5) and the stiff sidewall hinders hard starts.... The difference between these three tires and BFG 275/35/18's was ridiculous. I will be running an r -compound on my E30 but will have an extra set of wheels with DR's mounted... to get a good launch you need DR's or Slicks, in addition to a soft rear set up. The car has to be able to squat, meaning, the sway bar must be on the softest setting if adjustable, proper camber must be dialed in and of course, your suspension must be able to squat. Set your shocks on the softest setting etc.... not rocket science but it can make a huge difference.

Yeah, well the reall stiff sidewall of r-comp and street-autox type tires (leading to less longitudinal contact patch) doesn't really do much for straight line traction, but the soft compound and small void area do help a bit.

Interestingly enough, most of what I've seen points to beater cars with crappy tires and stock, small (but light) wheels getting the best quarter mile times. Crappy tires tend to have crappy sidewalls leading to more of a contact patch, but also to less rotational inertia (no sidewall reinforcement), and most people who get aftermarket wheels, even if they are as light as stock are pushing the mass further from the axis of rotation creating more of a moment of inertia regardless.

I think, for the most part, unless you're on drag radials or slicks, tire choice doesn't matter that much for quarter mile times.

[JGood]

Fair point. I think it has more to do with rotational mass, but still.

Yeah, that too. Weird thing is, I ran a full 1 mph faster then any other run, on my last run of the night, with my slowest ET, when using my heavy 16's and 205/45/16 all seasons. That's the run where I missed second twice and wheel hopped through first badly.

I don't understand the physics behind that. haha

[Wh33lhop]

I was basically sidestepping the clutch at 3k or higher, heard a loud bang as the driveshaft snapped all it's slack up, and the car went. No wheelspin. I honestly thought I was going to break something. I was using v710's that I did a nice burnout with... 205/55/14's.

I understand what you are saying about sidewall flex, but we are dealing with 200hp cars, I think the effect is minimal in comparison to tread compound.

Fair point. I think it has more to do with rotational mass, but still.

about 90% of the swaps I saw had open filters that looked like they'd been through a war. lazyness is a reason but I think ignorance plays a larger part.

It bugged me too, but I will be happy just to complete the swap and have the car fire up.

[nando]

Yeah, I think the idea is that by the time you're done with swapping the motor, the brake booster, doing the wiring, etc, they're not going to bother fabbing up an intake if they don't have to.

I'm just going to slap a CARB-legal filter on it until I can fab up a routed intake and heat shield.

about 90% of the swaps I saw had open filters that looked like they'd been through a war. lazyness is a reason but I think ignorance plays a larger part.

[JGood]

Yeah, well the reall stiff sidewall of r-comp and street-autox type tires (leading to less longitudinal contact patch) doesn't really do much for straight line traction, but the soft compound and small void area do help a bit.

Interestingly enough, most of what I've seen points to beater cars with crappy tires and stock, small (but light) wheels getting the best quarter mile times. Crappy tires tend to have crappy sidewalls leading to more of a contact patch, but also to less rotational inertia (no sidewall reinforcement), and most people who get aftermarket wheels, even if they are as light as stock are pushing the mass further from the axis of rotation creating more of a moment of inertia regardless.

I think, for the most part, unless you're on drag radials or slicks, tire choice doesn't matter that much for quarter mile times.

I was basically sidestepping the clutch at 3k or higher, heard a loud bang as the driveshaft snapped all it's slack up, and the car went. No wheelspin. I honestly thought I was going to break something. I was using v710's that I did a nice burnout with... 205/55/14's.

I understand what you are saying about sidewall flex, but we are dealing with 200hp cars, I think the effect is minimal in comparison to tread compound.

[Wh33lhop]

I noticed this at the E30 picnic. tons of hot air intakes, most of them extremely dirty, and many of them are really small (low surface area + dirt + hot air = shit). my own measurements have shown that no shield can double your intake temps quite easily, and that's a good 5-10hp loss right there.

Yeah, I think the idea is that by the time you're done with swapping the motor, the brake booster, doing the wiring, etc, they're not going to bother fabbing up an intake if they don't have to.

I'm just going to slap a CARB-legal filter on it until I can fab up a routed intake and heat shield.

[Wh33lhop]

I do have a Dinan chip, headers, and 2.5" exhaust, my intake is cone filter with a heat shield.

Keep in mind my r-comps didn't do much. I did run a 14.487, but my average run was a 14.6 @ 93.5-94.5 and I tried it with street tires for my last run of the night. I wheel hopped through first, missed second gear, missed second gear again, then finally got it into gear and took off. The time was a 14.9@95...

Yeah, well the reall stiff sidewall of r-comp and street-autox type tires (leading to less longitudinal contact patch) doesn't really do much for straight line traction, but the soft compound and small void area do help a bit.

Interestingly enough, most of what I've seen points to beater cars with crappy tires and stock, small (but light) wheels getting the best quarter mile times. Crappy tires tend to have crappy sidewalls leading to more of a contact patch, but also to less rotational inertia (no sidewall reinforcement), and most people who get aftermarket wheels, even if they are as light as stock are pushing the mass further from the axis of rotation creating more of a moment of inertia regardless.

I think, for the most part, unless you're on drag radials or slicks, tire choice doesn't matter that much for quarter mile times.

[nando]

Seems like a lot of DOHC guys have a straight-up cone filter (hot air intake), I'm not sure how much hotter IATs are with that but I doubt it helps much. Justin's heat shield and probably the fact that he's running a really tall first gear (equivalent to a G260 and a 2.93 or 3.25 he said, didn't he?) and didn't have too many traction problems is probably partially to blame, but a 13.9 is a lot quicker than I'd expect to be, even with some WR and a chip.

I noticed this at the E30 picnic. tons of hot air intakes, most of them extremely dirty, and many of them are really small (low surface area + dirt + hot air = shit). my own measurements have shown that no shield can double your intake temps quite easily, and that's a good 5-10hp loss right there.

[JGood]

Well, if everyone had a 2.8 stroker ix they could sidestep at 6 grand and take off like a bat out of hell it probably would :p



Damn, that's pretty quick. Justin's was sort of a freak of nature though.

You're running a stock M50TU on r-comps? No chip or anything?

Seems like a lot of DOHC guys have a straight-up cone filter (hot air intake), I'm not sure how much hotter IATs are with that but I doubt it helps much. Justin's heat shield and probably the fact that he's running a really tall first gear (equivalent to a G260 and a 2.93 or 3.25 he said, didn't he?) and didn't have too many traction problems is probably partially to blame, but a 13.9 is a lot quicker than I'd expect to be, even with some WR and a chip.

I do have a Dinan chip, headers, and 2.5" exhaust, my intake is cone filter with a heat shield.

Keep in mind my r-comps didn't do much. I did run a 14.487, but my average run was a 14.6 @ 93.5-94.5 and I tried it with street tires for my last run of the night. I wheel hopped through first, missed second gear, missed second gear again, then finally got it into gear and took off. The time was a 14.9@95...

[Wh33lhop]

they usually have it within 5 feet around here. it makes a pretty big difference for me to do a hard launch vs a normal take off.

Well, if everyone had a 2.8 stroker ix they could sidestep at 6 grand and take off like a bat out of hell it probably would :p

Mine is a few pages back. 14.4@94

Justin_l (sp?) ran a 13.9 I think.

Damn, that's pretty quick. Justin's was sort of a freak of nature though.

You're running a stock M50TU on r-comps? No chip or anything?

Seems like a lot of DOHC guys have a straight-up cone filter (hot air intake), I'm not sure how much hotter IATs are with that but I doubt it helps much. Justin's heat shield and probably the fact that he's running a really tall first gear (equivalent to a G260 and a 2.93 or 3.25 he said, didn't he?) and didn't have too many traction problems is probably partially to blame, but a 13.9 is a lot quicker than I'd expect to be, even with some WR and a chip.

[nando]

Hmmm... usually in autocross you don't have to do a drag race start as the first timing light isn't set right at the line.

they usually have it within 5 feet around here. it makes a pretty big difference for me to do a hard launch vs a normal take off.

[EtaSport]

it's been done, several times. ;)

true, props to the guys who do the work.

I find myself in most situations having a long starting straight on most autocross courses but still end up fishing tires far after the "start-off" area. I never launch but I like to get up to speed quick and it always spins. I haven't quite got the proper feel down for a good start. I watch some guys launch at the start and its such a waste.

The RS2's in that size were my next street tire choice actually. I suppose the e36 cant really be compared to the e30 since the multi-link is leaps above the trailing arm however I still like the e30 for predictability. My e30 is no straight line car so I dont complain plus the 3.73 diff and getrag doesnt help.

[rThor432]

-is anyone with a 3.0 or larger getting any traction what-so-ever?

My OBD-1 3.2 E30 has all kinds of traction. I hardly have to slip the clutch in first to ensure a good launch. That's with 225/50/15 RS2's set at 28-30 psi (depending on the day of the week) and a fairly compliant rear suspension. But of course my gearing is pretty weak.. It gets to 60 in a hurry, but I'm putting a 1:1 trans and 3.25 in the back soon, so I'll see if it is a tire roaster after that..

FWIW, like you said, the E36's hook up very well. My 3.2 M3 will not roast 245's unless you really provoke it. I'm running some decent 235's on it right now, and it doesnt even roast those.

[Jean]

It would be cool to see a 24v ix, but I dont think thats going to happen either.

-is anyone with a 3.0 or larger getting any traction what-so-ever? I know I'm comparing apples to oranges, but my 328 with software, catback, intake, m50 manifold, ASC delete, fan delete (yada/yada) will never spin its 245s even when provoked (really wouldnt spin 225s either) but my e30 destroys its 205 azenis on every occasion.

Its really annoying at the autocross because im probably losing a second at every start just easing on the throttle, i never go WOT at the start.

Hmmm... usually in autocross you don't have to do a drag race start as the first timing light isn't set right at the line.