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Discussion Starter · #1 ·
bmw forums are proving extremely not helpful with my questions and remembered that supraforums was awesome in question responses.

The compression ratio on the new bmw 335i is 10.2:1 with some tiny turbos. running stock at 306bhp.

i'm looking to pick up one of these upon it's release and was wondering if it modding it would be similar to the mkiv's BPU++ set up. stock boost is around 8.75psi i think it was.

i was thinking boost control, new piping, turbo timer, and bov. also, how high do you think those stock turbos will be able to boost? i don't want to blow my motor a month after i buy one lol. thanks in advance.

-zrvs
 

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Ex-hardtopper
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Not sure about the strength of the new engines, so I can't really comment on how they would fair when turning up the boost and by how much. However, if the motors are anything like the late 90's M3 motors (in terms of strength) then I don't think you have much to worry about. My friend Mike here in NJ has a 97 M3 turbo (GT35R) with a bone stock block (completely untouched) that is making 617rwhp and 628 ft/lbs...again, stock block (head bolts, headgasket included).

The BMW is going to be completely new, so I'm sure there's going to be some testing to be done to see how stout the setup really is.
 
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Discussion Starter · #4 ·
Boostrush said:
Not sure about the strength of the new engines, so I can't really comment on how they would fair when turning up the boost and by how much. However, if the motors are anything like the late 90's M3 motors (in terms of strength) then I don't think you have much to worry about. My friend Mike here in NJ has a 97 M3 turbo (GT35R) with a bone stock block (completely untouched) that is making 617rwhp and 628 ft/lbs...again, stock block (head bolts, headgasket included).

The BMW is going to be completely new, so I'm sure there's going to be some testing to be done to see how stout the setup really is.
thanks for the quick response. this makes me optimistic about upgrading the turbos to something like a hks t51r-kai in the future. i just posted above some pix of what the motor looks like. ahh man, i hope that this car will fair similarly to my old BPU supra! thanks again~ peace

-zrvs
 

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I'm back!
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"Equally surprising is that there is no audible indication of turbocharging, either — the characteristic intake whoosh and turbo whine are completely absent, and there's no bypass valve chuffle, either. The only clue that there's something else going on other than normal aspiration is a slightly bassier exhaust note. That, and the wallop of the torque plateau, giving the 335i a linear thrust that pulls eagerly to the 7,000-rpm redline."

Um....Gay.
 

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I sold my E46 330ci but I still browse the forums and can't see why I would want another bimmer.

335i (turbo)
3.0L DOHC bi-turbo @ ~8.52 PSI (6 cylinder, 24 valve) (N54 Bi-turbo Engine Pics)
300hp / 300 lb-ft tq

Unladen Weight: 3571 lb.
Power-to-weight ratio: 11.9
Brake Diameter: 13.7 / 13.2 inches (front/rear)

I don't know how accurate that is to what the production vehicle will be.
 

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264 Posts
zrvs said:
The compression ratio on the new bmw 335i is 10.2:1

i was thinking boost control, new piping, turbo timer, and bov. also, how high do you think those stock turbos will be able to boost?
I'd be more worried about what the engine will allow with 10.2:1 CR and pump gas.
 

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From my experience (good and bad), the BMW won't be quite what you want and the parts will be too pricey for what little they do, etc...

If you're after a new or newish car with a turbo and a market for mods.... *drumroll* Get an Evo/Sti.
 

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Ready. Set. Gone.
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Just wait and see what people do who have higher budgets than yourself. I wouldn't touch it until it is a proven set up..
 

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My advice...don't mod that car...yet.

You're talking about a completely new engine with direct fuel injection and a high compression ratio. If you mod anything, your warranty is screwed, and you'll be left with a new car with a blown motor. It's not worth the risk to be a guinea pig on this car, unless you have money to burn. Let shops figure out what works and what doesn't, wait a year or so, and then take advantage of that knowledge.

We always forget about history, but with the MKIV Supra, it was still considered huge to be BPU+++ (420+ rwhp) in 1997, which was about 4 years after the car debuted. APU took even longer, and you can argue that development continues even on this 12 year old platform.

Also, and this isn't BS, BMW has very intelligent ECU systems that record basically anything that BMW wants it to. The stealership can then play back everything you've done, including raising boost, etc. in order to deny your warranty. A family relative of mine is a BMW technician in Southern California, and I've talked about this subject (out of personal curiosity) for a long time. It's not worth the risk on an untested platform imho.

High compression ratio + aluminum block + ECU/warranty concerns = bad idea.
 

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The engine management will be the tough part for the tuners to work with in order to bump up boost or change turbos. I had a 95 M3 (OBD1) and they could do magic with it. It took several years for them to get the OBDII worked out to do similar things. Many people just swapped out the OBDII w/ OBDI brains. Then in 2000 when the E46 version of the M3 came out..... it was way harder to break the code. I bought an 03 with the plans to supercharge or turbo but tuning was such a nightmare I sold the car........ which led to the purchase of my Supra.
I even pursued the thought of going to a standalone EMS, but none of the guages or A/C would have worked,,,, that won't work in FL!
Now on to the longevity theory,,, The M3's had bearing failures from 00 all the way to at least 2003 because when I took mine in for regular service, they changed them out under warranty. Many people "spun" bearings and had major issues. I would do as others suggested, wait until it's out for a year and check with your BMW tech person to see how they're holding up.
Our 2000 M5, on the otherhand, is still rock solid and it just rolled up to 100k miles.
BMW's generally last a long time and hold together well, but the 1st of something totally new and different is going to be more risky.
 

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BMW Tech
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Wait for 1 year to go buy. The first year is going to have problems and also you will be seeing new mods coming out for it that may not even gain HP from.

And BMW most of the time changes the current model just a little bit. Like options or different bumpers.

So wait for a year then go nuts.
 
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Discussion Starter · #20 ·
thanks a lot for the great input. i wanted a lux sports car and i think this would be great. if i just wanted something to daily drive and eat things up i'd of course get another supra haha. STI's and EVO's can't pull nearly as hard as my BPU++ did.

yeah, think i'll wait on modding it. see now, i wish the BMW forums gave good response such as the supraforums. i think love this community more than i loved my supra haha. thanks again everyone! peace

-zrvs
 
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