Marcus & Trevor's Driveway Built Drag Car! (Build Journal)

Originally Posted by Commanderwiggin

Which one was your favorite?

depends on the power band.

If you have twin 62 mm chargers like I do 3,64 is very good as it allows to use higher rpms.

If its got more low end torque like a S54 with a single 68 mm turbo then 2,65 pulls and pulls and feels as if the pull will never end.

so many factors play their own roles.

so cant say this ratio or that is better.

Originally Posted by Twin_Turbo_S54

Marcus,

May God save your grandmother.

Regarding your bolt issues:
I am still on oem vib damper.

1- check the tightening specs on the bolts.

2- get your flyheel balanced, just a precaution. It may be off balance.

Btw, I've actually tried two os giken fly wheels, both brand new. But yes, I should probably balance everything from here on out before installing.

Originally Posted by Twin_Turbo_S54

I was able to use 2,65 / 2,81 / 2,93 / 3,07 with OS LSD.

Im sure it's "possible" but which model housing are you using? And with stock ring gear or modified?

Which one are you using?

I can massage just about anything to fit or even make the entire unit from billet if desired- but I respect the manufacturers settings and engineering a lot

Ive heard alot of things posted by you and am not sure if I really believe many- I know my os giken units and compatibility as I get direct support and supply from os giken usa

Sent from my GT-N7100 using Bimmer App

Originally Posted by wanganstyle

Im sure it's "possible" but which model housing are you using? And with stock ring gear or modified?

Which one are you using?

I can massage just about anything to fit or even make the entire unit from billet if desired- but I respect the manufacturers settings and engineering a lot

Ive heard alot of things posted by you and am not sure if I really believe many- I know my os giken units and compatibility as I get direct support and supply from os giken usa

Sent from my GT-N7100 using Bimmer App

OS Giken directly bought from OS Japan. I ve been in touch with OS japan.

Ring and pinion 210 mm bought from XYZ shops.

No massaging, no modifications, straight fit.

I dont care if you believe in me, I ve been able to hold the fastest 60-130 mph record of 4,23 s for the last 16 months.

So what I advise or comment has been tested to the extremes.

Marcus,

You may need to start by balancing the crankshaft & vib damper & flywheel & clutch all individually and then all assembled.

VAC sells a very nice VIB Damper, which I may get soon.

But to aid your case, I ve been able to rev all day long 9000-9200 rpm with zero issues, and mine is a stroker 3,500 cc as well.

So the main source could be balance related.

1st get all rotating parts individually balanced

2nd get them assembled and then balanced as an assembly.

3rd buy an oem vibration damper.

Guys,

A word of warning about the VAC damper that's built by ATI: It may not be designed for your power level.

When I asked VAC what power level the damper was designed for, they would not answer. (I'm assuming they don't know)

The reason why I bring this up is that I've been involved with quite a few custom BMW dampers from ATI, including some well over 1000rwhp. There are different damper ring sizes and rubber compounds for various power levels, so the damper really is...and should be designed exactly for your power level.

If you have any technical questions about this, I highly suggest getting in touch with ATI directly.

Originally Posted by PEI330Ci

Guys,

A word of warning about the VAC damper that's built by ATI: It may not be designed for your power level.

When I asked VAC what power level the damper was designed for, they would not answer. (I'm assuming they don't know)

The reason why I bring this up is that I've been involved with quite a few custom BMW dampers from ATI, including some well over 1000rwhp. There are different damper ring sizes and rubber compounds for various power levels, so the damper really is...and should be designed exactly for your power level.

If you have any technical questions about this, I highly suggest getting in touch with ATI directly.

Adam,

Does whp matter for the vibration damper or is it the frequency that happens at certain engine speeds which will destroy the crankshaft?

As far as I know, frequencies increase up to a point between x rpm and y rpm and cause the crankshaft and bearings to move, flex and destroy.

What matters whp or engine speed?

BTW, have you taken logs of your turbo speed sensor? I follow you with pleasure Adam.

Originally Posted by Twin_Turbo_S54

OS Giken directly bought from OS Japan. I ve been in touch with OS japan.

Ring and pinion 210 mm bought from XYZ shops.

No massaging, no modifications, straight fit.

I dont care if you believe in me, I ve been able to hold the fastest 60-130 mph record of 4,23 s for the last 16 months.

So what I advise or comment has been tested to the extremes.

Many are more extreme than you: please don't assume you are innovating or doing anything new.

So AFTERMARKET ring and pinion- NOT OEM BMW - thats what I was asking.

I could care less about supposed troll records: rolling start is weaksauce compared to drag launching sub 1.5second 60' at a strip with slicks full brake boosting.

I have set up 188mm bmw stock diff with stock gears and stock lsd to handle more power than you make; 30+ passes 1000rwhp and mid to low 9's' - video is all over the web for this car

Key point here is not my car nor my own claims - a well known local car and client- a reputable HONEST one

Sent from my GT-N7100 using Bimmer App

Originally Posted by Twin_Turbo_S54

Adam,

Does whp matter for the vibration damper or is it the frequency that happens at certain engine speeds which will destroy the crankshaft?

As far as I know, frequencies increase up to a point between x rpm and y rpm and cause the crankshaft and bearings to move, flex and destroy.

What matters whp or engine speed?

BTW, have you taken logs of your turbo speed sensor? I follow you with pleasure Adam.

Mert,

It's a function of power and frequency (RPM).

If you ran the engine on a Spintron, which basically spins the crank at a desired RPM without combustion, you will find harmonics are present. This is a function of the inertial loads from the rotating assembly (pistons, rods) Looking at the piston/pin mass alone, you have approximately 500 grams X 4300g (@8000 RPM) of deceleration at TDC which is 4,700 lbs pulling up on the crank.

The combustion event can be 1800+ PSI peak for a gasoline turbo, and over 3000+ PSI for nitromethane for example. Imagine 1800 psi acting across a 3.3" diameter piston. That's approximately 16,000 lbs force onto the crank, which is then released very quickly.

So we have approximately 20,000 lbs of force change very quickly on the crank. (Again, limited to only the piston assembly mass)

By changing RPM, we vary the force change a little bit, but the main amplitude change comes from combustion. So you can see that by varying power levels, which changes the peak cylinder pressure, that the required harmonic damping effect changes a lot.

The harmonic signature of the crank, or the frequencies that it resonates at, don't really change much with RPM....but the amplitude does. Most of the time with modified engines, the harmonic problem shows up because of spending more time in a problem area....or with added power, the problem area is bigger.

Oh...and I've attempted to take some logs of the turbo speed sensor, but what my little speed gauge reads, and what an EMS reads is different story. The EMS situation has evolved due to various reasons, so I don't have hardware in my hands currently.

Originally Posted by wanganstyle

I could care less about supposed troll records: rolling start is weaksauce compared to drag launching sub 1.5second 60' at a strip with slicks full brake boosting.

+ 1

Troll records are verified on famous pages and valid worldwide.

Originally Posted by PEI330Ci

Oh...and I've attempted to take some logs of the turbo speed sensor, but what my little speed gauge reads, and what an EMS reads is different story. The EMS situation has evolved due to various reasons, so I don't have hardware in my hands currently.

are you running sq6 on m54?

Marcus,

If you were to drop 300-400lbs in your car alone and get it down to the weight that the HPF Drag car is i have no doubt it would be faster.

That car needs some things figured out on it, i still feel like the 10.2 it ran was pretty weak all things considered (2600lbs, th400 ETC).

Good luck and i have a feeling it should do what you need it to!

Originally Posted by gringotegra

Marcus,

If you were to drop 300-400lbs in your car alone and get it down to the weight that the HPF Drag car is i have no doubt it would be faster.

That car needs some things figured out on it, i still feel like the 10.2 it ran was pretty weak all things considered (2600lbs, th400 ETC).

Good luck and i have a feeling it should do what you need it to!

I might take my subs/amps out but that's only about 100lbs. The HPF drag car needs more shakedowns and fine tuning. Its power to weight ratio should put it deep into the 9's no problem. I think I can get mine into the high 9's at mfest with fresher slicks and no subs. The street slicks we ran on last year were very old and dry.

Originally Posted by Twin_Turbo_S54

are you running sq6 on m54?

Mert,

I'm looking at a range of new options, but I have to wait a couple of months for the next software releases before we get pricing. It appears I've created a functionality list that most currently available ECUs can't support....

Originally Posted by PEI330Ci

Mert,

I'm looking at a range of new options, but I have to wait a couple of months for the next software releases before we get pricing. It appears I've created a functionality list that most currently available ECUs can't support....

Adam,
wish you luck.

2012 1,64 9,79

Originally Posted by m3micke

2012 1,64 9,79

I think you meant to post this in a different thread?

Originally Posted by m3micke

2012 1,64 9,79

A+ thread, would read again

Just an fyi.. but I was not able to build a dedicated drag car as after a week or two of deciding to do this I wound up having to move, time got limited and I didn't have the ability to start from scratch and still make MFest. So I've been working on improving the times on the LSB 6spd.