Single Turbo? What I need to know

[cloud9blue]

Car is relative stock when it comes to engine mods, just the standard FBO setup with JB4 and MHD backend flash. Tried running full e85 for a while with fuel-it stage 2 lpfp and TPI, but partial throttle response was a bit of hit of miss on with that setup. It was kind of annoying for the road course events I like to do with this car, so I went back to pump gas again.

I am seriously thinking of getting a decent ST kit to replace the aging stock twins and have been reading quite a bit on forums to catch on the recent ST development. My goal is to be around a conservative 500-550whp on pump gas with DI only and quick spool and good transient response. So probably a 6062 or even a 5862 turbo is enough for me.

Anyway, I just want to use this thread to compare notes with the rest of you and gather information that might be helpful for other members down the line.


- ST Kit
At the moment, it seems like Doc Race and Motiv are probably the best complete kits available on the market. And I am still kind of deciding between the two.

Not really considering the VM/ACF and ADE kits since they have long lead time and questionable availability. Not gonna bother with the low end offers like On3 and etc. Nothing wrong with saving some money, but I just don't have the energy to deal with potential issues of those kits. If I gonna do this, I would rather get it right the first time. Btw does FFTEC still make N54 kit?

Motiv
Pros:
- Durable manifold design, whole kit seems very well put together and reliable; these kits have been around for a few years now without any hardware failure. I know quite a few track cars (road course) run Motiv kits.
- Clean bottom mount design and less heat related issues down the road because of that
- Well executed pre turbo O2 bungs, with long heat sink so your O2 will last longer
- Short runner length, faster spool (for mid size turbos) and better transient response? I know these are somewhat debatable depending on the actual execution.
- Recirculated wastegate dumps is an option, less noise and less smell during stop and go traffic?
Cons:
- Log style manifold is more restrictive? Again, debatable. But Motiv's manifold definitly have sharper bends and smaller OD that the other high quality ST kits.
- Have to replace the stock style passenger side engine mount with a custom one made of PU. Not a fan of PU mount, especially that close to the hot parts. The last PU mount I had from Black Forest Industry started to deform just after two months of winter driving...
- Turbo is hard to reach, more of hassle to replace and perform checks on it. Bottom mount just don't have the same visual impact as a nice top mount lol
- Probably the most expensive ST kit out there

DOC Race
Pros:
- Equal length runner, good for top end power I suppose, which is what this engine needs
- Twin scroll manifold! Good for quick spool.
- Get to keep your stock style motor mount, don't have use a custom PU mount
- Easier to access and replace turbos and stuff
- Top mounts just look so damn cool!
- More affordable comparing to the Motiv offerings
Cons:
- Much longer runner length, bad for spool and transient response maybe? Again, my turbo size will be pretty moderate comparing to those +600whp builds, so not sure how big of issue would that be.
- Top mount brings hot parts closer to some of the plastic engine parts (VC, WW tube). But probably manageable with the heat shield, ceramic coat, turbo blanket, and heat wrap/tapes.
- Have to relocate coolant reservoir, not a big deal, just a bit of extra work
- O2 heat sink is bit undersized according to Chris post on the ADV sensors, so your O2 will die faster maybe? Would like to hear more on this.

PCV
Currently, the only PCV mod I have is the RB PCV valve and cap on the low pressure side, which actually solved the smoking idle that I experienced after I went full catless. The car desperately need an OCC on the high pressure side though. Car spend a lot of time in boost because of all the track days I do. I can tell from the sparkplugs after a few days on the road course, that the engine is burning through some oil from the intake side.

Since my goal is a moderate 500whp on pump gas, the engine probably won't be seeing any boost higher than 20psi. So aside from installing a BMS OCC on the high pressure side and vent the line coming out of the OCC to the intake filter (keeping the flapper valve), I don't see the need for any other mods.

Tapping the ports on the intake side and bypassing the low pressure PCV system with an external one like the stuff RB is selling is a bit overkill for my goal IMO (feel free to argue with me on that!). But they do seem like a good solution for those running high boost and chasing big powder.

Ignition
At my power level, I probably would be ok with the stock coils and just run some colder plugs and gap them closer than stock, but for piece of mind, it might be best just get the upgraded coil kit from Bimmerlife or Precision. It looks like both kits perform the same, despite the different approach each took (dumb vs. smart coil, etc.). I am personally leaning toward the Bimmerlife kit, since it comes with 3d printed connectors that requires less work to install.

I am running stock plugs still btw. Seems to doing alright all these years, so other than replacing them after each track season, I didn't bother to experiment with colder plugs. The only time I had problem with it is when I spilled oil on the VC during oil change and didn't bother to clean it up, which caused misfires at WOT because of the oil pooled in the spark plug wells.

O2
This is the part I would really like to discuss more with you guys. What's the verdict on the choice of O2 for ST right now? Are stock ones bound to die quick as a pre-turbo sensor? Is ADV sensor a must for ST? Any other equivalent or better alternatives?

Fueling
Not really interested in PI until someone figure out a properly integration controller that can actually control individual injectors for our engines. The current spray and pray, all or none solution is just not my cup of tea. It only takes a split second to grenade an engine at high rev with lean detonation, and IMO the current solutions out there are just not fast enough to get things under control if one of your DI injectors decided to crap out at WOT. The stage 2 lpfp should be plenty for my pump gas power goal.

I am still on original factor injectors (no idea what the index number is, but the car was a MY09 made in late 08), which has been trouble free so far (knock on wood). Did have to replace the stock hpfp myself two years ago, as the pump was starting to die on track and cold start after running full e85 for a few months. It probably was just old and the lower lubricity of e85 and the stress from all the track days I did during those month just finally killed it.

Cooling
The car has a 7" VRSF FMIC (the old non-HD version). Seems to be doing a good job. But after I switched to DCI intake (had to ditch the stock airbox since it doesn't fit with TBI), I did notice the IAT tends to climb and stabilize at 140F during a 20 mins session. Not sure it is worth the trouble and the potential loss in transient response of a larger FMIC like the 7.5" stepped core that VRSF now sells. Would rather say the $700 for other stuff if the benefits of a larger core is not great for my power level.

I am currently running CSF radiator, PPK aux rad and Dinan OC (single core at the passenger side). My current setup should be more enough for street use, since a lot guys are just fine running big ST setup on stock oil cooler Might have to loop in an extra OC for track use though, considering I can still hit 260-270F with the stock twins when pushing hard on a hot day (I do hear ST engines do run cooler oil temp than twins because of less heat buildup at the CHRAs and better turbo efficiency).

Drivetrain
My car is an 6at. Personally, I never understood the need for trans cooler, since our trans don't really run that hot from the data I gather on track. The highest trans temp I have seen is 105C (which isn't all that hot IMO), and that's after 20mins on hot lapping on road courses. And my trans still shift as smooth as the day I picked this car up brand new from the dealership almost 7 years ago. I have been replacing my trans fluid pretty frequently though (twice now at 58k miles), using Redline D4.

Already got LSD, diff brace, subframe bushings, and M3 arms front and back, toe arms, coildovers and all that on the car. The only weak points I can think are the half shafts and gearbox itself. But for the power level I am aiming and for my intended use (not gonna do any hard standing launch), I don't think upgrades on those are necessary (not like there is any good AT upgrades anyway).

Installation
As much as I would do the install myself, I just don't have the time nor the space to do a project as extensive as this. So this will be done by a shop. Both kits have pretty good fitment that I think any competent person can put together with the right tools, so I don't think this will be a problem. But do let me know any issues you have run into though!

Tuning
I have been running different versions of JB from BMS since 2010. Great stuff and very happy with the products and the support BMS gave to this platform over the years. Probably just gonna stay with the JB4 and get a custom backend tune. But I am interested in hearing some actual experiences from those who jumped ship to the Motiv boostbox.

[blaster400]

I went with the MOTIV kit a couple years ago and have been very happy with this set-up. This year I switched to Boost Box with custom tune by Jake H. which made a huge difference. I’d highly recommend that you consider this tuning option. Also, you’ll want to use the ADV sensors because the stock ones will go bad with the added heat. If you haven’t flashed your tranny with xHP Stage 3 you really need to do this.

[R.G.]

I can appreciate the research you've done so I'll give a quick run down of my experience if will help at all.

DocRace kit. Was in on the initial group buy. Think that was 6-8 months ago or so. Installed in my garage with free time in the evenings. Not difficult for a newb like me, just takes a little time if first go around. Should be cake for a shop.

PCV - Just the modified OEM valve

I just put Eldor coils in and they've been solid. Was not getting responses from either of the upgraded kit vendors but weren't really needed anyway in my case.

ADV O2s. They're a must. Your stock sensors won't last and #s will be off due to placement relative to turbo. I burned thru 2 sets in 2k miles before my ADV's. No issues since.

I run E40/E50 with a DIY walbro 455 bucket. Trims struggle at times but has been sufficient.

I run an ATM IC and it does its job. Unless shooting for big #s I would think the 7" you have would be sufficient

I run the PPK aux. rad as a trans cooler. It sucks. OEM heat exchanger did a better job at keeping temps pegged unless airflow is sufficient enough for rad. You're on the right thought process with that.

Tuning: Boostbox pro tuned. Love it. Car has never been funner to drive. At 20psi the car is reliable, makes me smile and keeps me from turning it into a coffin. Feel free to PM any Q's, good luck! You won't regret it.

[cloud9blue]

I went with the MOTIV kit a couple years ago and have been very happy with this set-up. This year I switched to Boost Box with custom tune by Jake H. which made a huge difference. I’d highly recommend that you consider this tuning option. Also, you’ll want to use the ADV sensors because the stock ones will go bad with the added heat. If you haven’t flashed your tranny with xHP Stage 3 you really need to do this.

What actual differences do you feel with boostbox vs. the JB4 you were running before?

Totally forgot about the xHP flashtool. Looks like I have to read up on that as well. I have been pretty happy with the alpina flash all these years when paired with pump backend flash. That said, it was kind of wonky with the E85 backend flash from bms. Had a lot of shift flare at partial throttle which wasn't there with the pump tunes...

[cloud9blue]

I can appreciate the research you've done so I'll give a quick run down of my experience if will help at all.

DocRace kit. Was in on the initial group buy. Think that was 6-8 months ago or so. Installed in my garage with free time in the evenings. Not difficult for a newb like me, just takes a little time if first go around. Should be cake for a shop.

PCV - Just the modified OEM valve

I just put Eldor coils in and they've been solid. Was not getting responses from either of the upgraded kit vendors but weren't really needed anyway in my case.

ADV O2s. They're a must. Your stock sensors won't last and #s will be off due to placement relative to turbo. I burned thru 2 sets in 2k miles before my ADV's. No issues since.

I run E40/E50 with a DIY walbro 455 bucket. Trims struggle at times but has been sufficient.

I run an ATM IC and it does its job. Unless shooting for big #s I would think the 7" you have would be sufficient

I run the PPK aux. rad as a trans cooler. It sucks. OEM heat exchanger did a better job at keeping temps pegged unless airflow is sufficient enough for rad. You're on the right thought process with that.

Tuning: Boostbox pro tuned. Love it. Car has never been funner to drive. At 20psi the car is reliable, makes me smile and keeps me from turning it into a coffin. Feel free to PM any Q's, good luck! You won't regret it.

Great, thanks for the info! appreciate the first hand feedback.

[Payam@BMS]

I would give VM/ACF a chance before saying no lol. I believe he has them in stock now and is building a bunch of bottom mount EFR kits as we speak.

[email protected]

[Terry@BMS]

The Motiv kit is OK but has its limitations. I like the cleanliness of a bottom mount and the easy O2 sensor changes when needed, but the performance has been limiting. Waiting for an ACF bottom mount for our new build. For top mount ACF all the way. DocRace seems like a decent alternative though.

On o2 sensors I like the ADVs in theory but I seem to get a lot of customer reports with problems. Payam here ran them and liked them though. Personally I currently prefer and run the NGK o2 sensors.

On fueling I think your assessment of port injection (with the JB4 integration) is off base. But if you are not planning to run port injection I'd question whether its even worth doing a single turbo. You're probably better off running twins in the 600whp range. You'll have better spool, cleaner engine bay, fewer headaches, IMHO. It's not like the automatic trans is going to survive more than a few passes at 650whp anyway.

[cloud9blue]

I would give VM/ACF a chance before saying no lol. I believe he has them in stock now and is building a bunch of bottom mount EFR kits as we speak.

[email protected]

Well that's good to hear. Gonna hit him up with an email sometimes. I am waiting for the ACF bottom mount to be done as well, looks promising. But I would rather not be the beta tester for a new kit.

[cloud9blue]

The Motiv kit is OK but has its limitations. I like the cleanliness of a bottom mount and the easy O2 sensor changes when needed, but the performance has been limiting. Waiting for an ACF bottom mount for our new build. For top mount ACF all the way. DocRace seems like a decent alternative though.

On o2 sensors I like the ADVs in theory but I seem to get a lot of customer reports with problems. Payam here ran them and liked them though. Personally I currently prefer and run the NGK o2 sensors.

On fueling I think your assessment of port injection (with the JB4 integration) is off base. But if you are not planning to run port injection I'd question whether its even worth doing a single turbo. You're probably better off running twins in the 600whp range. You'll have better spool, cleaner engine bay, fewer headaches, IMHO. It's not like the automatic trans is going to survive more than a few passes at 650whp anyway.

Appreciate the honest input, Terry. Would love to hear the specific problems that people have with the ADV and the reasons for your preference with the NGK (haven't heard much about that before, but again, I didn't quite followed the O2 discussion that went on the last two years until just recently).

I agree twins would be a cheaper and easier solution for my power goal. But the issue comes down to reliability. I have yet to see a hybrid twins that last for people who spend decent amount of time on road course. The wastegate will just wear out again eventually and rattle like a mofo, just like the stock ones on mine. And the reliability of the CHRAs on these twins are still bit of his or miss even after all these years. That's the reason I am set on ST instead of twins.

[Terry@BMS]

In terms of road racing reliability you have a valid point, I don't have a lot of experience with that aspect. Still, not having port injection is going to kill you. I presume also no WMI? Are you willing to use unleaded race gas full time (in race mode) rather than E85?

On the ADV sensors anything I say will probably be misinterpreted so I'll leave others to share their experiences with them. I've had no issues with the NGKs though on our various applications.

[cloud9blue]

In terms of road racing reliability you have a valid point, I don't have a lot of experience with that aspect. Still, not having port injection is going to kill you. I presume also no WMI? Are you willing to use unleaded race gas full time (in race mode) rather than E85?

On the ADV sensors anything I say will probably be misinterpreted so I'll leave others to share their experiences with them. I've had no issues with the NGKs though on our various applications.

Anything particularly wrong with running pump gas aside from the lower power output? 500whp is more than enough for my intended goal. I am not insane like the rest of you, lol.

I run a light mix of e85 (e30-e40) every now and then on and off track. Figure it cleans up the timing and lower the EGT a bit, which can't hurt.

WMI is a no no for me. Too many points of failure for that on road course, I would rather run full e85 and a proper PI if I really want more power.

[foe516]

CES is supposedly coming out with steedspeed twin scroll bottom mount kit. probably a lot cheaper than motiv. thats the one i would get hands down, one of the best manifold makers out there.

[R.G.]

It's been a while but I believe it's the temp issues that roasts the OEM O2s
OEM: https://www.boschautoparts.com/en/au...s?partID=17102

Again, been a while (thankfully) but the ADV's are just LSU4 sensors adapted to our platform. Designed for higher operating temps.

http://www.bosch-motorsport.com/medi...9147659pdf.pdf


Edit: No experience w bottom mounts but I access my O2s from wheel well. Takes me 15 minutes.

[xLOGANx]

It's been a while but I believe it's the temp issues that roasts the OEM O2s
OEM: https://www.boschautoparts.com/en/au...s?partID=17102

Again, been a while (thankfully) but the ADV's are just LSU4 sensors adapted to our platform. Designed for higher operating temps.

http://www.bosch-motorsport.com/medi...9147659pdf.pdf


Edit: No experience w bottom mounts but I access my O2s from wheel well. Takes me 15 minutes.

these are very reasonable at 130.00 each,for a pair it's 260.00,good share!

[Terry@BMS]

Anything particularly wrong with running pump gas aside from the lower power output? 500whp is more than enough for my intended goal. I am not insane like the rest of you, lol.

I run a light mix of e85 (e30-e40) every now and then on and off track. Figure it cleans up the timing and lower the EGT a bit, which can't hurt.

WMI is a no no for me. Too many points of failure for that on road course, I would rather run full e85 and a proper PI if I really want more power.

If you're just shooting for 500whp and don't mind another 1000-1500rpm worth of lag over stock turbos, then in that case a single would be fine for you. You'd have no issue making that on E30 or something similar in a solid and reliable setup.

[Sticky]

I went with the MOTIV kit a couple years ago and have been very happy with this set-up. This year I switched to Boost Box with custom tune by Jake H. which made a huge difference. I’d highly recommend that you consider this tuning option.

I'm guessing you mean for single turbo setups in particular?

[Sticky]

CES is supposedly coming out with steedspeed twin scroll bottom mount kit. probably a lot cheaper than motiv. thats the one i would get hands down, one of the best manifold makers out there.

They've been 'coming out' with this for years.

Twin scroll bottom mounts will be nice to see though but I think AC-F already has this done.

[cloud9blue]

They've been 'coming out' with this for years.

Twin scroll bottom mounts will be nice to see though but I think AC-F already has this done.

Yeah. Even doc race kit took years, I remember first hearing about their mock-up manifold back in 2012 or something. No point of holding out when there are plenty of other great kits on the market.

[cloud9blue]

I would give VM/ACF a chance before saying no lol. I believe he has them in stock now and is building a bunch of bottom mount EFR kits as we speak.

[email protected]

btw, I placed an order with Anthony last week. hoping to get the kit shipped before the end of next month

[nikitino25]

Top or bottom mount?

[cloud9blue]

Top or bottom mount?

top, like the look of the top better

[Payam@BMS]

btw, I placed an order with Anthony last week. hoping to get the kit shipped before the end of next month

Ahhhh sweet! He told me that he sold one more, I believe the manifold is almost done actually. You might have it sooner than you think, I believe its just when the turbo arrives at this point.

[nikitino25]

top, like the look of the top better

With what turbo? I'm considering the same type of setup/power goals.....

[cloud9blue]

With what turbo? I'm considering the same type of setup/power goals.....

6062. The lag should be barely noticeable. Thought about 5862 as well, but just want to leave some headroom down the line if I want a bit more power.

[cloud9blue]

Ahhhh sweet! He told me that he sold one more, I believe the manifold is almost done actually. You might have it sooner than you think, I believe its just when the turbo arrives at this point.

Oh sweet, mine is the one with recirculated dump pipes. The early the better of course. Trying to piece together other parts right now.

If if you don’t mind, I might bother you some questions instead of Anthony.