Finally going single. I have tons of questions

[twinturbos]

Hi y'all, I am glad I finally found a place that shows off serious builds instead of that "stance" trash.

I have had my 2007 335i for 5 years now running JB4, charge pipe, downpipes, 7" vrsf fmic on the stock twins. Put out 370whp on a mainline dyno. My stockers are pretty much on their way out so it's time to upgrade.

I've been looking at all kinds of turbo kits, single and twins and there are a lot of choices. My goal is to keep the engine going as long as possible so I'm not aiming crazy numbers. Car currently has around 98k miles / 156k kms.

So.. the power goal is around 550-625RWHP, thinking of around 500whp for the first year(2019) and add more supporting mods after.

I am leaning towards the DOCRACE kit with a 6266 gen2(?? 6466 ??) for now. I already bought the 335D tank and started the relocation (without running an additional line from new location to thermostat/waterpump) At the same time I'm putting in a new water pump, thermostat, thermostat to oil filter housing hose with aluminum fitting, water pump to thermostat hose, changing the small hoes that goes on the engine supply pipe(aluminum)

Looks like I'm going to have to go with the VRSF charge pipe for relocation tank as my current one does not fit.
I've heard about the crank hub possibly.. slipping? Is that something that I need to be worried about at the power level I'm aiming ?
I sold the JB4, intake, What is the easiest way to get back on the road after the single turbo install ? Should I get another JB4 or should I be looking at other options ?
An important thing to keep in mind is that I don't have access to ethanol here, only pump 94. I am looking into water/meth but probably won't be running it this year.

I am hoping to make this into my build thread, thank you all for answering my questions and letting me know of any other things that I need to know when going single and aiming around 600whp.

 

[Aaron]

If your goals are only 600 wheel, why the push for a single? Twins can reliably put down those numbers, and they'll crush the single in spool and response.

You should absolutely be worried about the hub slip issue. The crank bolt capture from VTT is fairly inexpensive ($100) and seems to have solved the majority of these issues.

 

[The Convert]

I also would stick to twins for that power level. Had the current twin offerings been ou when I first went single, I would have stuck with twins.

 

[Erichale77]

I agree with Aaron. Upgraded twins will be more than enough for your power goals and they will spool faster. Plus you wouldn't need to change much if anything.

 

[silverstreak18]

If you're going to be in that power range for the first year and then going to want more afterwards then go single. But if you really are planning on sticking in that 550-600 hp range then twins would be a more cost effective solution. Just make sure you go with a quality set of turbos because labor will run you about 12 hours to have them replaced each time.

 

[twinturbos]

Hi everyone, thanks for your answers. I want to run around 500 the first yesr then around 600 until the engine fails eventually. I then want to build another one and go for more so I guess the beet way to do this is to start by going single right away?

 

[doublespaces]

This motor will hold up at 600 for a pretty good clip if taken care of so you might be talking about a 5 year plan or more. If you don't mind having some lag down low or starting with a tiny turbo then going single should be fine, but you're in for a larger up front cost, obviously.

The easiest way to get back on the road AND be tuned is to use a JB4, no doubt. You don't have to go through the street logging required of flash tunes. But a good tuner can get you in the ball park in 1-2 revisions. If you want to run 25 psi the next day, then JB4 has been the way I've seen that done.

 

[twinturbos]

For the first year, I guess the stock fuel system should do the job except maybe I should upgrade the LPFP. I'm thinking a "stage 2" pump should be enough? I've been actually thinking of building one myself. I am not sure I understand the whole deal about going bucketless... It provides better flow however I don't want to risk starving the pumps/engine. What's the minimum fuel level one should keep with a bucketless?

doublespaces, I've been beating the living sh*t out of the engine for the past 5 years, I'm hoping it's still healthy Basically every single time the car comes out to play .. it's to play... highway pulls, twisties runs... It's not a daily so when it comes out it ain't to cruise around except if I'm going on a road trip and wanna be in the "racecar"

 

[twinturbos]

I was thinking of going with the 335is/550i clutch for now, should I change the flywheel for something else or should I keep stock one ?

 

[Aaron]

You will need to upgrade the LPFP in order to hit your power goals. I'm not very well read on the bucket vs bucketless, so I can't really help there. From the reading I did, all of the testing companies were unable to reproduce any of the "in theory" problems with going bucketless.

Your HPFP will be close to maxxed, but it can support 550-600 on gas, it'll just be pushed. Initially I would've said this will lead to premature HPFP failures, but I've been running mine high duty cycle, maxxed, for a good 20,000 miles without any issues, and VTT runs their shotgun (Oversped) units without premature failures.

The 335is clutch likely will not hold your power. Mine slips at 470 whp/512 wtq.

 

[Torgus]

You will not regret a single turbo. They can make the most whp on pump gas period. I have no E85 access and run 93 and meth.

Unless people have seen another 570whp 93 octane twin dyno I am unaware of...

T51R mod if you like the sound

 

[Aaron]

GC's are making what, 900-1000? And you're saying the ethanol adds 400whp? You're delusional.

 

[Torgus]

GC's are making what, 900-1000? And you're saying the ethanol adds 400whp? You're delusional.

?

 

[twinturbos]

You will not regret a single turbo. They can make the most whp on pump gas period. I have no E85 access and run 93 and meth.

Unless people have seen another 570whp 93 octane twin dyno I am unaware of...

T51R mod if you like the sound

I'm sure going single is the best way to avoid having to change setup again... How is the lag ? which turbo you running ? 570whp on 93+meth sounds pretty good, what supporting mods do you have ?

I've been thinking of the T51R mod, it sounds kinda cool and a friend of mine actually runs a T51R on his skyline and it's really growing on me.

 

[Torgus]

I'm sure going single is the best way to avoid having to change setup again... How is the lag ? which turbo you running ? 570whp on 93+meth sounds pretty good, what supporting mods do you have ?

I've been thinking of the T51R mod, it sounds kinda cool and a friend of mine actually runs a T51R on his skyline and it's really growing on me.

I have a 6466 I have not dyno'd yet. I was poking fun at the VTT 570whp 93 octane twin dyno. A 6266 on 93 should be about 570ish on this platform it seems. A 6466 a bit more. Add charge pipe meth even more. Iirc 700whp has been done on direct port meth and 93. At some point you end up injecting a ton of meth for fuel which is risky...

I dont mind the lag. Most people with singles dont complain about it from what I read. It is what it is. If you want gobs of low end tq stick with twins. A single will be easier on your engine.

I think the t51r mod sounds awesome. I also have diff whine from my solid mounts etc. Its just another sound of performance imo but seriously it's bad ass. If you dont like turbo whistle dont do it.

 

[Aaron]

You're saying no twins can hit 570 on pump. The GC's have hit 900 for sure, and I thought 1000, with ethanol. So in essence you're saying the ethanol added 400+ whp. Either way, if the GC's can support nearly 4 digit power numbers, I'm sure half that won't be a problem.

 

[Torgus]

You're saying no twins can hit 570 on pump. The GC's have hit 900 for sure, and I thought 1000, with ethanol. So in essence you're saying the ethanol added 400+ whp. Either way, if the GC's can support nearly 4 digit power numbers, I'm sure half that won't be a problem.

I'm saying the GCs have been out for what 3 years? I have not seen another 570whp 93 pump dyno. That is all. I dont recall a 900 or 1000whp gc dyno either. I could be wrong.

 

[Erichale77]

Highest run on GC's was 830WHP and 902WTQ with 28.8lbs boost. But that was with a FULLY built engine with stand alone and custom tuning. For anyone else they should be good for 750WHP. No twin has broke 1000HP yet (to my knowledge), only single turbo

 

[Aaron]

Ok, I stand corrected, GC's maxxed out was 830whp. But their Stage 3's have crossed 900. Still twins. Which is odd since it's impossible to get over 570 with twins.

So the GC's are perfectly capable, it's people's shit engines that are to blame for not hitting high power numbers. Got it. Glad we cleared that up. Wait, why again are we saying no twins can hit 570 if they're hitting 900+?

 

[twinturbos]

Lol here we go... debates starting
So...
Stock internals N54 with 98k miles on it.
Obviously catless downpipe, secondary cats replaced with vibrant resonators.
Stage 2 LPFP - will have to look into this, suggestions welcome
JB4 + backend flash I'm guessing - are there base maps available for download for the docrace 6266 ?
charge pipe with tial bov
vrsf 7" fmic
94 octane gas...

Should be able to push 550whp ? -> on the docrace with a gen2 6266