I have a modded 335i. The low end torque is a lot of fun, but the downside is that traction can become an issue. Mine is auto and it starts in 2nd because in first, traction is an issue. The other problem is that above ~5500 rpm, the car really doesn't do anything since the turbos run out there. Guys upgrade to RB's for more power of course, but also to shift the powerband up some.

FWIW, the new record on stock turbos is 481whp. Not that it's reliable or safe, but they will flow up there. Guys with upgraded turbos go well north of 500.

 

you actually contradict logic here, several of the high power guys actually run stock fans and radiators on 24 row or less coolers with absolutely no issues. putting a fan on the cool results in lower cooling due to the fan being a restriction at speed. fans are for traffic thats it, your cooling at speed comes from natural air flow of the car moving through the air. i question if you have any experience based on your comments especially recommending the gtm kit which is known to have both fitment issues and parts missing, and the going on about cooling the turbos with coolant which isnt needed what so ever. ball bearing also has absolutely nothing to do with boost threshold like your saying it only affects lag or how quickly it reachs set max boost after boost threshold.

 

yeah you have no idea what you're talking about.

 

says the guy with absolutely no proven experience to the guy who does what supposedly cant sure your opinion holds SOOOO much weight. pretty obvious you havnt built a z nor even read a single build thread. so far you have provided nothing here other then add on comments rehashing what has already been said before, problem is in this instance your rehashing things that apply to sleeved engines not a stock sleeve engine.

 

dimsler, glad you joined and commented here.

However you should know that Jerry knows a lot, but more importantly he applies his wide knowledge base in a very logical manner. That's the difference between knowledge and wisdom.

Now, I disagree with Jerry on a few small points and I hope that you can find a way to do so with some etiquette, otherwise, GTFO of my thread.

 

Cool to know, thanks!

Those stock turbos are TINY TD03-10Ts I have to believe that those stock N54 turbos are running way past the choke line in the higher RPMS, i.e. not much happens after 5500 rpms. The build I'm looking at gets VERY close to the choke line, but doesn't go past unless I'm shooting for 420+ RWHP.

 

Jerry, Please check out this website.

http://www.squirrelpf.com/turbocalc/...=2&map_sel0=85

This link will recreate all the #s I entered. Go to the bottom and select the TD05-14B
I entered 450HP = 375 WHP.

FYI, these plots appear to be very accurate as they come out the same as my math.

My concern is that I'm not entering realistic #'s I'm going to call a couple injector manufacturers and see if someone can give me an accurate BSFC.

Anyways, cool site, play around and let me know what you think.

Cheers

 

its not bad but as i said before it really dosnt take into account turbine housings which plays just as important a role in the turbo making power. the fact it uses the tiny 8cm^2 housings on a engine that desires much larger which reduces the max power the turbos will be capable of producing, also while flow should be the same at x power level regardless of engine combo we know thats not true. a perfect example of this (will go a little off topic but bear with me)is when comparing the old billet precision 6765 on a evo and a supra, the evos where able to get 1000 with iirc a t4 .68 housing but no matter what the housing the most the supras where able to only squeeze 900 from it and big ol v8's had trouble doing more then 650 with a single one.

the math and calculators are great for a starting point but sometimes it needs a little experience and knowledge on the setup because often times it dosnt work quite that way especially because theres dozens of things they dont factor in such as is it even possible to hit pressure ratio x on engine combo y, it also dosnt take into account what the actual boost threshold will be, what the spool time will look like, or how vvt affects the setup. this is one of those instances(the VE's are a little low as well you have displayed there.) and your going to have a really hard time getting to that, your definitely not going to be able to hit that pressure ratio. the borg warner match bot if a far better tool because you dont put in a power you fill in the specs of the engine and turbo combo and it tells you a rough estimate of what it will make, and if its even possible.

i know from experience the current line of precision turbos are one of the fastest spooling on the market and from what ive been told by precision is the 1.32 housing i have is about equal to the .94 open housing, combine that with my quick spool setup which improves spool by around 33% by time and down low it performs like a .63 t4 housing down low before the second volute opens up thats a little bigger then what your going with but the advanced wheels should put spool roughly equivalent with the quick spool(and from what ive seen of other setups here probably a bit better, gotta remember the wheels on those things are only about 25% smaller then the precision 67mm but you have two, same for exhaust wheels) and i cant even hit 19.71 psi at 2800 rpm.

thats why precision dosnt even bother with compressor maps because people get hung up on them without realizing that it is really only a starting point and there is far more to it, alot of it cant even be done with math but requires CFD to get any true estimate. if a combo is close to the limit then its definitely not the combo to go with, your goal should be something that crosses through the max efficiency island

 

Thanks again for taking the time, you've given me a lot to think about.

I will be disappearing for a couple months and research is going to come to a halt as the busy season ramps up for me. I wad hoping to possibly meet you guys in Hawaii but the projection mapping project feel through.

Let me part with a few last thoughts as I'm between flights atm and write this via phone.

The 14b exhaust housing is actually 6cm where the GReddy 18G and 20G are 8cm. However, the 14b has fairly large turbines.

I am tempted to move forward with this simply out of curiosity. I can afford whatever. However, I rally enjoy the pursuit of originals and experimenting. The 14b is relatively easy to upgrade either the hot or cold side. I an exited about the prospects of trailblazing a different option for out platform especially considering that they are getting much cheaper and are landing into the hands of people on budgets.

I had a lot of fun in my college days with my friends as expert junkyard tuners. Now that i have money, it would be cool to continue down that path one more time if it meant giving younger versions of me the information they need.

In the end, if I'm completely wrong, I can afford to make it right. I kind of look to the N54 as an example of how underwhelmingly small turbos can be made to work.

 

hmmm website i got info off of must be wrong then i def wouldnt try those tiny housings then everything on the vq platform shows bigger is better for exhaust housing. turbines dont do much when the housing is to small outside of slow down the spool. your best sizing the vq as a 3.5L v8 instead of a typical import v6 they need larger turbine housings, not necessarily turbine wheels, they like the flow even more then a 3.4L 2jz

honestly if you want to be different try borg warner efr, they apparently have had all the kinks worked out at this point as ford is having no issues with them on there eco boost engines nor are the f1 engines. they also have titanium exhaust wheels and built in boost recirc valves to keep spool up. ive wanted to see someone run them and twin 6258's(smallest they make) would do what you want, the ecoboost f150 is able to make 515 ft lbs of torque at about 2900 rpm from a 3.5L with them, i think thats probably the only turbos that is going to be able to make the amount of power you want with the power range you want granted at a price premium i would expect probably closer to 3400 rpm on the vq though because it isnt direct injected with high compression.