I LEARNED'D something today!

[Razi]

It's probably due to my worn out bushings.And my shocks seem fine.

I always had wheelhop, and from what I know from other 240 owners, it's pretty common.
Modified by Razi at 11:15 PM 3/22/2010

[MinisterofDOOM]

Yeah, wheelhop is pretty common with IRS rear-drivers. It's one of the reasons solid axles can be better for drag racing.

[Razi]

Supposedly, all the people that replace the thin piece of metal on the subframe, it eliminates wheelhop.http://www.rpsport.net/product/

Don't want the spend 50 bucks though...might make one myself if I'm bored enough.

[PEZi]

do a solid axle swap!

pick like one of the nismo frontier or x-terra axles

[Razi]

I feel all OCD when I think of my old suspension arms and the worn out bushings!Ahhhhhhhhhh.

[MinisterofDOOM]

So, can someone give me a small breakdown on the differences an SRI and a CAI gives in the powerbands?

In general, a longer intake tract on the same engine means more torque down low. A shorter intake tract means more power up high. That's why trucks usually have really tall intake manifolds versus cars with the same motor. It all has to do with intake air velocity. That's ignoring intake air temp, which is usually high with SRIs as they soak in engine bay heat rather than getting good cool fresh air.

Supposedly, all the people that replace the thin piece of metal on the subframe, it eliminates wheelhop.

http://www.rpsport.net/product/

Don't want the spend 50 bucks though...might make one myself if I'm bored enough.

Cobra Mustang guys use similar solutions for their wheelhop problems as well.

[PEZi]

i luv my solid axle....

[Razi]

i luv my solid axle....

I luz everything on your truck!

Cobra Mustang guys use similar solutions for their wheelhop problems as well.

Good to know, maybe I'll buy or make one.

[PEZi]

I luz everything on your truck!

it luz yooo too

[Razi]

So like, we replaced our Q45's blown shocks a few weeks ago because the car handled like s*** and was a big improvement, and my mom said she can't feel a difference. -.-

[MinisterofDOOM]

What did you replace 'em with? I LOVED the Tokico blues on my Q.

[Razi]

Tokico Blues ftw.That's what we have, feels good!

[PEZi]

leaving before site maintenance

later doods

[Razi]

Peace yo!I'm out too.

G'night MoD!

[krimsonviper]

IRS rear-drivers

What?

In general, a longer intake tract on the same engine means more torque down low. A shorter intake tract means more power up high. That's why trucks usually have really tall intake manifolds versus cars with the same motor. It all has to do with intake air velocity. That's ignoring intake air temp, which is usually high with SRIs as they soak in engine bay heat rather than getting good cool fresh air.

So then what Pezi and those people I mentioned said earlier, are wrong? For low end power increase, get a CAI?

[MellowZ32]

what up sexy putas!

[PEZi]

What?

So then what Pezi and those people I mentioned said earlier, are wrong? For low end power increase, get a CAI?

IRS stands for independent rear suspension.... rear wheel drive in this case

and i think MoD is hitting a completely different point... the intake manifolds themselves are typically longer on trucks for torque... but not necessarily the intake itself... this is further proved by those cute little short ITB's on some cars... they are USELESS for torque and only improve high end

my thought on the intake itself still stands.... SRI

[MellowZ32]

Oh little KV has so much to learn!

[MinisterofDOOM]

What?

So then what Pezi and those people I mentioned said earlier, are wrong? For low end power increase, get a CAI?

Yeah, Pezi's got it backward. Longer intake for low-end torque (and thus power) and shorter intake for better high RPM aspiration (and thus high end power). SRI will help throttle response across the board, though.

IMO short-rams are a joke, and a marketing ploy developed to profit from pseudoscience. Hot air charge is ALWAYS bad. Improved throttle response at the cost of air density (and thus power) is not a good trade. This is why in the days of carb-mounted air cleaners, performance cars would use cowl-induction hoods. They isolated the intake charge from engine bay temperatures without even having to relocate the filter. These days, with remote air filters, there's absolutely no good reason to feed your car hot air.

[krimsonviper]

Why can't a CAI?

[PEZi]

Yeah, Pezi's got it backward. Longer intake for low-end torque (and thus power) and shorter intake for better high RPM aspiration (and thus high end power). SRI will help throttle response across the board, though.

in that case BMW's DISA system is flawed.... but its not... because i've felt it work in person

[PEZi]

This is why in the days of carb-mounted air cleaners, performance cars would use cowl-induction hoods. They isolated the intake charge from engine bay temperatures without even having to relocate the filter.

hey... i still live in those days pal

[MinisterofDOOM]

DISA fits with what I said. It uses long runners below ~4500rpm and short ones above it.Nissan has used variable intakes ("00vi or MEVI") on the Maxima's VQ as well, in the same way: long runners at low rpm, short at high rpm.



EDIT:Pezi: that's what the 720 needs: a vacuum operated cowl induction hood like the Chevelle had. It would look badass.http://www.youtube.com/watch?v=K6Plv8-zTxIThere's the primary cowl for normal operation, and the secondary flap that opens under heavy throttle to feed more air.

[MellowZ32]

I am sooooo hungry right now!

[krimsonviper]

Long runner?

[PEZi]

DISA fits with what I said. It uses long runners below ~4500rpm and short ones above it.Nissan has used variable intakes ("00vi or MEVI") on the Maxima's VQ as well, in the same way: long runners at low rpm, short at high rpm.

Yes the DISA valve controls the variable length intake manifold on the M42/M44 motors. Located inside the intake manifold, it gives better torque at low revs by closing keeping the intake runner long but after about 4500rpm, it opens up by and makes the intake runners shorter for more horsepower.

but yes... a cowled hood would be sweet lol

[PEZi]

[krimsonviper]

Nevermind, I get the runner phrase. I'm posting naked in my bed from my iPhone. I have no idea what BMW's system is, but it sounds like the have a 2 part intake system: one part of it on the long end of the intake for colder air and at a certain engine speed, switches over to another opening for quicker breaths?

[MinisterofDOOM]

That somebimmerguy quote is saying exactly what I said. "Gives beter torque at low revs by intake runners long" "After 4500rpm it makes the intake runners shorter for more horsepower." Exactly what I said.

[PEZi]

That somebimmerguy quote is saying exactly what I said. "Gives beter torque at low revs by intake runners long" "After 4500rpm it makes the intake runners shorter for more horsepower." Exactly what I said.

dammit i quoted the wrong one.... here's the full description... its even in the service manuals for E46'sJust to further elaborate on Iceman00's explanation of the DISA valve, its a flap designed to change the length of the intake manifold runners. its actually a really fascinating concept and BMW did some serious R&D on this.

with engines, there are usually two routes you can go with intake runner lengths: shorter for better low end power or longer for better high end power. well, BMW came up with a way to put two lengths into one intake manifold and have a flap change the runner length, thus optimizing power across the entire power band. the DISA valve is the piece that changes the length of the runners. during low engine speeds it stays closed but about half way through the RPM band (i dont remember where) the flap opens up changing the length. but in order for BMW to make an intake manifold with dual length runners fit in that sardine can of an engine bay, they had to get creative. thats why our intake manifolds have more tubes than an oil refinery. especially compared to the old M50 intake manifolds you can see the differences made to capitalize on the DISA valve. all things considered though, i think BMW did a great job. the space where they "added" intake runner tubing was basically unused space.

now, just for the sake of saying it, its totally possible to put another intake manifold on these cars that uses no DISA valve (say an M50 intake manifold). i have absolutely no idea how well it would run but i would imagine it would improve power in the top end and you'd definitely lose power in the low end. in fact, while doing research for this swap i found tv show posted on youtube where a guy had an M50 intake manifold put on his supercharged M54 engine to get more power. apparently they are a lot better for supercharged applications on our cars than the manifolds that incorporate the DISA valves. but i dont remember where i saw the video so if someone is interested say so and i'll try and find it again.