Gold Standard of Weight Reduction - E90 on a Diet

[SJ_1989]

So the time has come to start weighing the car since round 1 of fab work is now complete! I thought 2700 lbs race weight without a driver was a bold goal when Efab Motorsports and I started down this path of extreme weight reduction. I think it is very possible this is the lightest E90 that exists that's not a tube chassis (not sure if one even exists either). I'm blown away by how much weight we were able to take out!

As of now, the car weighs 2375 lbs!

DISCLAIMER: This isn't the final race weight. The car was weighed in the following configuration, however, everything else that should be on the car is on the car besides what's listed below:

Excludes:

• Front and rear doors (not gutted with glass)
• Front windshield
• Electronics (will be minimal)
• Front fenders

Still includes:

• Non-run flat rear tires
• OEM rear wheels
• Front and rear crash bars

I really think 2550 lbs race weight is achievable. What's even more crazy is there are still areas where we can cut weight! Can't wait to start racing this car, it's going to haul some ass.

[Sticky2]

This may be a lot to ask but can you list what you removed and replaced?

[SJ_1989]

This may be a lot to ask but can you list what you removed and replaced?

I'll try my best to summarize what's been done thusfar that netted weight reduction, particularly things that others can benefit from that are more street car than race car. To be honest, and this will probably upset a few people, I won't go into detail of everything that was done. Not because I don't want to share information with everyone, but because this car is going down a path where we've applied "secret sauce" that's going to make it competitive and hopefully hang with the big boys (personal goal). And obviously the time and money spent on it. I will say that the majority of the weight reduction comes from what I list below though.

Engine / Drivetrain

• MFactory lightweight flywheel
• Hood exhaust
• HVAC delete
• Power steering delete
• 3 gal aluminum fuel cell mounted in trunk
• OEM DME enclosure cut out of engine bay

Suspension / Brakes / Wheels

• Park brake delete
• 15" rear brake conversion with Wilwood calipers
• ABS delete and cut out enclosure from engine bay
• Deleted OEM master cylinder and brake booster and replaced with pedal box
• Lightweight front skinnies and rear wheels
• Bias ply front and rear tires
• Front sway bar delete

Exterior

• Passenger headlight delete

Interior

• Interior fully gutted including sound deadening
• Minimal electronics
• Aluminum dash
• Aluminum driver seat
• Carbon fiber sunroof delete

[Tony@VargasTurboTech]

Getting there but still got a long way to go my friend. We just weighed our drag car yestersday, lets just say, its substainally lighter than that and we weighed it with stock wheels, and tires all the way around...

[SJ_1989]

Getting there but still got a long way to go my friend. We just weighed our drag car yestersday, lets just say, its substainally lighter than that and we weighed it with stock wheels, and tires all the way around...

With a cage or no?

[Efabmotor]

Tony, as someone who has built a few e90’s and this car specifically I’m just going to say bull$#@!, and pics or it didn’t happen. There’s maybe 20 lbs of extra steel in this car left, now if it’s on a 9” and a total back half car I’ll believe it, but as a stock unibody with the rear irs there’s no was to be substantially lighter. Also I did not know you could have a full chassis built in China

[Chris@VargasTurboTech]

Tony, as someone who has built a few e90’s and this car specifically I’m just going to say bull$#@!, and pics or it didn’t happen. There’s maybe 20 lbs of extra steel in this car left, now if it’s on a 9” and a total back half car I’ll believe it, but as a stock unibody with the rear irs there’s no was to be substantially lighter. Also I did not know you could have a full chassis built in China

Hah! We'll post pics and progress when we're ready, but we definitely will. I'm not directly involved (read that: at VTT helping turn wrenches) with this build but know about it. As per usual when Tony gets an idea in his head, it's pushing the envelope, and he disappears from conversations/text/the planet while working in "the lab". It will be good to see where we eventually land, and same to you with your project. Regardless, these are going to be MUCH lighter cars than the platform has seen. That's a good thing.

Chris

[Payam@BMS]

Tony, as someone who has built a few e90’s and this car specifically I’m just going to say bull$#@!, and pics or it didn’t happen. There’s maybe 20 lbs of extra steel in this car left, now if it’s on a 9” and a total back half car I’ll believe it, but as a stock unibody with the rear irs there’s no was to be substantially lighter. Also I did not know you could have a full chassis built in China

Do you have more pictures of the car? Great work to get it to sub 2400lbs already.


@Terry@BMS Eventually we'll have to do this to the 135i, what's race weigh now on yours 2800lbs?

[Tony@VargasTurboTech]

Tony, as someone who has built a few e90’s and this car specifically I’m just going to say bull$#@!, and pics or it didn’t happen. There’s maybe 20 lbs of extra steel in this car left, now if it’s on a 9” and a total back half car I’ll believe it, but as a stock unibody with the rear irs there’s no was to be substantially lighter. Also I did not know you could have a full chassis built in China

Awesome, call bull$#@! all you want. It will just make it that much more fun when the car is finished. But I find it interesting a shop we have no idea who you are is butthurt our car is lighter than someone elses, and all of sudden you are taking shots from you computer. Oh i see, you signed up for this site just to make that post. Got it. Good ole internet. Cheers mate

To answer the OP's post. This is with a full cage, doors on the car, all windows on the car, trunk on the car, with drag wing. When the car is fully together we will reweigh, and not post the weight of course, we will simply post the results from the strip. Its funny, I never post build threads or things like that. Keep in all in the front pocket until its time tolay it down at the track. Much more fun that way

[Weehe]

Join date September 2017 - Tony: you just joined for this post!

Also Tony: Our car is way lighter than yours, but we will never back up that claim.

Classic Tony

[SJ_1989]

Hah! We'll post pics and progress when we're ready, but we definitely will. I'm not directly involved (read that: at VTT helping turn wrenches) with this build but know about it. As per usual when Tony gets an idea in his head, it's pushing the envelope, and he disappears from conversations/text/the planet while working in "the lab". It will be good to see where we eventually land, and same to you with your project. Regardless, these are going to be MUCH lighter cars than the platform has seen. That's a good thing.

Chris

It's a very good thing and will allow these cars to put up some impressive times!

Do you have more pictures of the car? Great work to get it to sub 2400lbs already.

@Terry@BMS Eventually we'll have to do this to the 135i, what's race weigh now on yours 2800lbs?

Take a look at my build thread on here. Bunch of pictures of what has been done to get it to where it is.

Awesome, call bull$#@! all you want. It will just make it that much more fun when the car is finished. But I find it interesting a shop we have no idea who you are is butthurt our car is lighter than someone elses, and all of sudden you are taking shots from you computer. Oh i see, you signed up for this site just to make that post. Got it. Good ole internet. Cheers mate

To answer the OP's post. This is with a full cage, doors on the car, all windows on the car, trunk on the car, with drag wing. When the car is fully together we will reweigh, and not post the weight of course, we will simply post the results from the strip. Its funny, I never post build threads or things like that. Keep in all in the front pocket until its time tolay it down at the track. Much more fun that way

If you're lighter than me with the same configuration then hats off to you because I have a good feeling what you did to get there and you are ahead of me. But, you can't claim to be the lightest without proof

Join date September 2017 - Tony: you just joined for this post!

Also Tony: Our car is way lighter than yours, but we will never back up that claim.

Classic Tony

At the end of the day all that matters is ET. Whether you decide to crank up the boost or attack the root problem of these cars being too heavy, it doesn't matter. But this is the lightest race E90 that exists until proven otherwise.

[SJ_1989]

I mentioned 2550 lbs race weight is achievable and it most definitely is. This is essentially race weight and it's sitting at 2570 lbs. Already got it planned to go back for round 2 of weight reduction next year to get it to 2500 lbs.

Keep in mind this is still a unibody IRS car with factory body panels and a 10 point cage

[Sticky]

I know you're running an N54 but as this is chassis related moving to 3-Series -> E9X section

[Sticky]

Very well done weight reduction here by BimmerBoost member @SJ_1989 who managed to get his E90 BMW 335i down to an incredible 2570 pounds. That is in race trim ready to go on the trailer but as you will read below he got it to 2375 pounds with some parts missing.

It's an incredible job and almost 1000 pounds less than stock. Rule of thumb this means he easily picked up a full second in the 1/4 mile if not more.

So the time has come to start weighing the car since round 1 of fab work is now complete! I thought 2700 lbs race weight without a driver was a bold goal when Efab Motorsports and I started down this path of extreme weight reduction. I think it is very possible this is the lightest E90 that exists that's not a tube chassis (not sure if one even exists either). I'm blown away by how much weight we were able to take out!

As of now, the car weighs 2375 lbs!

DISCLAIMER: This isn't the final race weight. The car was weighed in the following configuration, however, everything else that should be on the car is on the car besides what's listed below:

Excludes:

• Front and rear doors (not gutted with glass)
• Front windshield
• Electronics (will be minimal)
• Front fenders

Still includes:

• Non-run flat rear tires
• OEM rear wheels
• Front and rear crash bars

I really think 2550 lbs race weight is achievable. What's even more crazy is there are still areas where we can cut weight! Can't wait to start racing this car, it's going to haul some ass.

I'll try my best to summarize what's been done thusfar that netted weight reduction, particularly things that others can benefit from that are more street car than race car. To be honest, and this will probably upset a few people, I won't go into detail of everything that was done. Not because I don't want to share information with everyone, but because this car is going down a path where we've applied "secret sauce" that's going to make it competitive and hopefully hang with the big boys (personal goal). And obviously the time and money spent on it. I will say that the majority of the weight reduction comes from what I list below though.

Engine / Drivetrain

• MFactory lightweight flywheel
• Hood exhaust
• HVAC delete
• Power steering delete
• 3 gal aluminum fuel cell mounted in trunk
• OEM DME enclosure cut out of engine bay

Suspension / Brakes / Wheels

• Park brake delete
• 15" rear brake conversion with Wilwood calipers
• ABS delete and cut out enclosure from engine bay
• Deleted OEM master cylinder and brake booster and replaced with pedal box
• Lightweight front skinnies and rear wheels
• Bias ply front and rear tires
• Front sway bar delete

Exterior

• Passenger headlight delete

Interior

• Interior fully gutted including sound deadening
• Minimal electronics
• Aluminum dash
• Aluminum driver seat
• Carbon fiber sunroof delete

[Stevenh]

Fun read! I've always felt weight reduction has always been under shared online. Question: I thought the term 'race weight' was effectively the weight you lined up at, driver included. Am I off?

[vrsixxxxxx]

wow that's impressive. A 135 might be 2300 in with the same settings.

[SJ_1989]

I know you're running an N54 but as this is chassis related moving to 3-Series -> E9X section

No problem, and thanks for the article!

Question: I thought the term 'race weight' was effectively the weight you lined up at, driver included. Am I off?

It can be interpreted either way, that's why I mentioned it was without a driver. There's a few miscellaneous items missing but a bit more weight will be taken out too for the "final weigh" so the car should still be in this ballpark.

[SJ_1989]

wow that's impressive. A 135 might be 2300 in with the same settings.

After some napkin calcs I think it's possible to get this car sub 2400 lbs still on factory body panels (which I'm sticking to for now because some classes require it) with what we planned for it. That's a year or two out though. Got to get the car making passes first and see where we sit.

[maxnix]

So what we have here is two car chassis strippers arguing about which undriveable on the street car is lighter? Reminds me of the old days when cars were on frame. My Hotrod buddies had an old Edsel with just a frame and engine a couple of chairs on it and instruments on the steering column. It was was real light and fast but totally useless.

[Tony@VargasTurboTech]

So what we have here is two car chassis strippers arguing about which undriveable on the street car is lighter? Reminds me of the old days when cars were on frame. My Hotrod buddies had an old Edsel with just a frame and engine a couple of chairs on it and instruments on the steering column. It was was real light and fast but totally useless.

Huh, it was "Real light, and fast, but totally useless" Isn't that the definintion of a completely USEFUL race car? Real light, and Real fast. Its a race car, what else is it supposed to be comfortble and quiet?

[Stevenh]

So what we have here is two car chassis strippers arguing about which undriveable on the street car is lighter?

Yah!!!! Let's go back to the 998,089th post about which car made 3whp more on a different dyno on a different day...

/sarcasm

[SJ_1989]

So what we have here is two car chassis strippers arguing about which undriveable on the street car is lighter? Reminds me of the old days when cars were on frame. My Hotrod buddies had an old Edsel with just a frame and engine a couple of chairs on it and instruments on the steering column. It was was real light and fast but totally useless.

I don't even know how to respond to this lol

[Sticky]

Question: I thought the term 'race weight' was effectively the weight you lined up at, driver included. Am I off?

I consider it what the car weighs as driver weight is such a large variable it never made sense to me to include it.

[Roll up or pull up]

I love you bro!