[SlowE92]

Recently blew both turbos on my 335i. Started her up just fine and drove for about 20 minutes and then limp mode, smoke pouring out of the exhaust. I cheaped out on 19T turbos, they lasted around 30k miles, which was A LOT more than I expected I'd get out of them I have around 12k budget and can either get some pure stage 2's, or go single, but I don't know if my budget would allow for the single because I heard it gets pricey. I have port injection and charge pipe injection, walboro 450, index 12's, 7.5 intercooler, jb4/bef with controller, basically every supporting mod for hybrid turbos. Not looking to break any records but 600 whp is plenty of power for me. Any other supporting mod needed for a single? Reason I want to go single is I have absolutely no access to E85 unless I buy it in 54 gallon drums, and i'm tired of spending $600 to buy it and ship it to me and then have to store it. I do have access to race gas though. Any advice is greatly appreciated. Also I have never installed a single turbo nor have any experience installing one so I may or may not have to pay a shop to install it for me, unless anyone knows of a good DIY.

[oVeRdOsE.]

as you might know, I was in the same boat not so long ago.

You wont find a nice an clear DIY, but still, there's few nice video on youtube.

And I think the main reason why, is the installation is pretty straight forward.

Key benefit on a ST over a twin :
- less heat
- better access (less time consuming on maintenance)
- in most cases, less low end torque, and higher hp (safer for a stock n54)
- reducing complexity ( no vacuum canister, less oil and coolant line, less piping, less O2 sensor, less boost solenoid. And the end less point of failure)
- more turbo choice if you got like with a T3 or T4 flange.
- sound (exhaust and turbo if you go t51r mod)

Of course, those kit seems to be more expensive than a plug n play set of twins if you go higher quality.
I saw the ON3 kit a 2700$usd, but I read some people adding few hundred of dollar to complete the kit.

There's a lot of ST kit available, some popular, some more underground. it's insane.

After my research I went with speedtech for those reason :
- recirculated waste gate exhaust ( quieter)
- solid reputable brand with ton of options.
- Pulsar turbos on this kit are cheap. And they are water cooled too.

Few cons :
- owner told me there's absolutely no deals on those kit, and 3 months after he did a black friday deal....
- if you are out of US, customs and taxes are insane and owner won't do anything to help you on that. (apparently he did got issue back in the days)
- Not the best sounding ST because of the exhaust manifold setup. A tubular equal length will get you this sweet L6 turbo sound. However, Im getting a single exist with 1-2-1 with : HFC+ vibrant resonator + valved muffler. 3''.

Finally you seem to have all the supported mod to get your ST running. BEF+JB4 is what I did, mainly because I already had those and I'm going methanol injection. (here we dont have E85 nor something higher than 91 oct, there 94 oct but known as not so good)

If you want to keep your car for a long time, I think the cost difference TT to ST will be marginal on the long run.

For costing : my kit is the top mount 6262 BB, I added a filter and turbo blanket and it costed 4300$ usd. There was a 300 or 400$ off on black friday.

I didnt get the valve cover blanket, since it was a bit expensive, but I got a welder black blanket instead.

For part to complete the kit :
- copper sealant
- mac solenoid
- wiring
- heat shield sleeve for multiple line and wire : ie : brake line, oil line, coolant, a/c line, electrical wiring, etc.
- exhaust galsket where the OEM met the ST downpipe
- silicone spray to protect the exhaust heat wrap.
- vacuum hoses

[Mustafa.e92]

Over dose covered pretty much everything you need to know. Go single you won’t regret it

[SlowE92]

Originally Posted by oVeRdOsE.

as you might know, I was in the same boat not so long ago.

You wont find a nice an clear DIY, but still, there's few nice video on youtube.

And I think the main reason why, is the installation is pretty straight forward.

Key benefit on a ST over a twin :
- less heat
- better access (less time consuming on maintenance)
- in most cases, less low end torque, and higher hp (safer for a stock n54)
- reducing complexity ( no vacuum canister, less oil and coolant line, less piping, less O2 sensor, less boost solenoid. And the end less point of failure)
- more turbo choice if you got like with a T3 or T4 flange.
- sound (exhaust and turbo if you go t51r mod)

Of course, those kit seems to be more expensive than a plug n play set of twins if you go higher quality.
I saw the ON3 kit a 2700$usd, but I read some people adding few hundred of dollar to complete the kit.

There's a lot of ST kit available, some popular, some more underground. it's insane.

After my research I went with speedtech for those reason :
- recirculated waste gate exhaust ( quieter)
- solid reputable brand with ton of options.
- Pulsar turbos on this kit are cheap. And they are water cooled too.

Few cons :
- owner told me there's absolutely no deals on those kit, and 3 months after he did a black friday deal....
- if you are out of US, customs and taxes are insane and owner won't do anything to help you on that. (apparently he did got issue back in the days)
- Not the best sounding ST because of the exhaust manifold setup. A tubular equal length will get you this sweet L6 turbo sound. However, Im getting a single exist with 1-2-1 with : HFC+ vibrant resonator + valved muffler. 3''.

Finally you seem to have all the supported mod to get your ST running. BEF+JB4 is what I did, mainly because I already had those and I'm going methanol injection. (here we dont have E85 nor something higher than 91 oct, there 94 oct but known as not so good)

If you want to keep your car for a long time, I think the cost difference TT to ST will be marginal on the long run.

For costing : my kit is the top mount 6262 BB, I added a filter and turbo blanket and it costed 4300$ usd. There was a 300 or 400$ off on black friday.

I didnt get the valve cover blanket, since it was a bit expensive, but I got a welder black blanket instead.

For part to complete the kit :
- copper sealant
- mac solenoid
- wiring
- heat shield sleeve for multiple line and wire : ie : brake line, oil line, coolant, a/c line, electrical wiring, etc.
- exhaust galsket where the OEM met the ST downpipe
- silicone spray to protect the exhaust heat wrap.
- vacuum hoses

I was also looking at the speedtech kits because the Doc Race kits look really expensive, though they do look nice. If there is better performance rather than cosmetic difference between the two then I'd maybe opt for the Doc race kit but my knowledge between the two is extremely limited. I cheaped out on 19T's so I want to do it right this time. I do live in the US so I think the single kit for me is a little cheaper. I'm somewhat torn on what size turbo to get. Some people say for 600hp to just get the 5862, but for the same price I can also get the 6266. My one bottleneck is I don't have a dedicated garage anymore and any work I do on my car will be in my driveway, and am currently in the middle of winter lol. Thank you for the write up.

[oVeRdOsE.]

this mod is what the market consider like a ''stage 3'', and imo any 'stage 3' car, you should have a garage . You'll run in issues for sure.

If you read the HP rating on those turbos, be careful, those numbers are out from the turbo manufacturer himself, and most of the time on E85. Rule of thumbs you add a safety factor when estimating your goals, mainly for the other item around the engine, the tune and the fact you'll run pump gas.

My 6262 is 'rated' 900bhp, and realistically , iirc, it's around 600bhp. You remove a good 20% if you want to see pump gas numbers + xx% from other factor. I went smaller for the response, and I should do good hp anyway.

A precision 6266 was my 1st choice. Some with stock engine are running 6466 and youll be close to your 600whp.

It's been a while, but doc race is a complete kit, with a tubular or cast manifold option. The tubular is known for the best sounding N54.
you have the option for a real twinscroll with 2 waste gate, where the speedtech is single wategate. I dont even know if this will make a difference on a N54 with the tune option we have.

The reason I didnt go with them : cost and open dump.

[SlowE92]

Originally Posted by oVeRdOsE.

this mod is what the market consider like a ''stage 3'', and imo any 'stage 3' car, you should have a garage . You'll run in issues for sure.

If you read the HP rating on those turbos, be careful, those numbers are out from the turbo manufacturer himself, and most of the time on E85. Rule of thumbs you add a safety factor when estimating your goals, mainly for the other item around the engine, the tune and the fact you'll run pump gas.

My 6262 is 'rated' 900bhp, and realistically , iirc, it's around 600bhp. You remove a good 20% if you want to see pump gas numbers + xx% from other factor. I went smaller for the response, and I should do good hp anyway.

A precision 6266 was my 1st choice. Some with stock engine are running 6466 and youll be close to your 600whp.

It's been a while, but doc race is a complete kit, with a tubular or cast manifold option. The tubular is known for the best sounding N54.
you have the option for a real twinscroll with 2 waste gate, where the speedtech is single wategate. I dont even know if this will make a difference on a N54 with the tune option we have.

The reason I didnt go with them : cost and open dump.

Yeah, I use to have my own garage and was able to have my car on jacks in the garage for as long as i wanted to but that isn't the case for me anymore unfortunately I have a friend thats a diesel mechanic and he lets me use his shop, although only on the weekends when theyre closed. Is the T4 divided more beneficial than the open? I thought with the divided you would need to utilize 2 wastegates and the open you would only need 1.

[oVeRdOsE.]

Originally Posted by SlowE92

Yeah, I use to have my own garage and was able to have my car on jacks in the garage for as long as i wanted to but that isn't the case for me anymore unfortunately I have a friend thats a diesel mechanic and he lets me use his shop, although only on the weekends when theyre closed. Is the T4 divided more beneficial than the open? I thought with the divided you would need to utilize 2 wastegates and the open you would only need 1.

I'm not so sure about if a divided is better than open, I need to see proof or even a CFD for that.

Might have an impact for the scavenging effect, so the firing order help the exhaust flow and not work against it.

Doc and speedtech got divided manifold. I assume speedtech is mainly for dual fueling bank (oem), because it wont benefit of a twinscrool with a single wastegate ?


Are you able to leave the car on the lift? Because in those kind of job, if it's not a experimented mechanics doing many ST conversion a year, for sure you'll forget some stuff and wait them for shipping. Especially the ''while I'm there'' items.

in example, before putting back the engine, I did order a front main seal shield ( so if the strap slip, it wont be sucked in the engine). Small insurance, that took few days to arrive.

'My clutch was the worst that delay my project , ordered in may 2023, received on october 31st 2023.

[STATIC A$TRO]

how are yall doing your heat management?

[oVeRdOsE.]

Originally Posted by STATIC A$TRO

how are yall doing your heat management?

good question I still looking closely on pictures for ideas.

For valve cover :

1 - Metal plate like the Doc Race. I was planning to use a cooking pan and fold it with a home made folding machine aka few 2x6. But too tight for a clean job imo.

2 - My favorite, the speedtech valve cover blanket. Too expensive for me.

3 - Reflective tape. A lot of people using this, but I really hate the look.

4- Welder blanket and some tyewrap. There's some black one that would look sleek.

5- modify the original heat shied. I tried, it was shit, I removed it. The downpipe was touching it.

6- any customs plate. Like lazer cut steel plate to kevlar custom plate.

For the exhaust not more solution but heat wrap. However, I cover the heat wrap with a silicon spray from Design Engineering Inc

I should have wrap the dump pipe, but I didnt.

For the wires, brake line and a/c line I use heat wrap with velcro for 1'' and more, and a heat sleeve for smaller item. Some of the sleeve I cut it open to wrap around and I use a stainless steel tyewrap.

For the exhaust manifold, you can't really wrap this, it can cause issue like cracking. However, I ceramic coat it with 3-4 coat of ceramic spray from VHT.
This is the cheap way, I dont know if it will last or even do anything.

And finally, a turbo blanket of course.

[SlowE92]

Originally Posted by oVeRdOsE.

I'm not so sure about if a divided is better than open, I need to see proof or even a CFD for that.

Might have an impact for the scavenging effect, so the firing order help the exhaust flow and not work against it.

Doc and speedtech got divided manifold. I assume speedtech is mainly for dual fueling bank (oem), because it wont benefit of a twinscrool with a single wastegate ?


Are you able to leave the car on the lift? Because in those kind of job, if it's not a experimented mechanics doing many ST conversion a year, for sure you'll forget some stuff and wait them for shipping. Especially the ''while I'm there'' items.

in example, before putting back the engine, I did order a front main seal shield ( so if the strap slip, it wont be sucked in the engine). Small insurance, that took few days to arrive.

'My clutch was the worst that delay my project , ordered in may 2023, received on october 31st 2023.

There are just so many variables that I'm stuck on for the Pulsar there is a .85 A/R turbo and a .96 A/R. I know with the .85 I will get quicker spool but it's harder on the rods, vs the .96 which has a slower spool but easier on the engine? Just picking your brain on it. I also notice that the .96 is an open housing vs the .85 is a divided housing. With the divided housing would I still utilize 2 bank fueling?

[SlowE92]

Originally Posted by STATIC A$TRO

how are yall doing your heat management?

Not sure yet.. I think there is an option to have the hot side manifold ceramic coated. I can also get a coil cover for a couple hundred.

[oVeRdOsE.]

Originally Posted by SlowE92

There are just so many variables that I'm stuck on for the Pulsar there is a .85 A/R turbo and a .96 A/R. I know with the .85 I will get quicker spool but it's harder on the rods, vs the .96 which has a slower spool but easier on the engine? Just picking your brain on it. I also notice that the .96 is an open housing vs the .85 is a divided housing. With the divided housing would I still utilize 2 bank fueling?

yes, the O2 sensors are in the exhaust manifold, so divided.

However, a lot of people suggesting going single bank. I tried to find some cons, and apparently there's none ? I was worried that if 1 bank go lean or rich, the engine will limp no matter what on a dual bank fueling.
Now if I have 1 single bank, how it will know if a bank go bad ? dont know !

Other than this question key benefit are :
- 1 primary O2 (wide band) and 1 secondary ( normal ). cheaper to replace. You keep the black wire O2s.
- Primary O2 less prone to break because of the heat. The location is after the turbo hot side on the downpipe.
- Way more easier to swap since its now accessible from the top
- less issue with JB4 or MHD
- Overall more reliable.

You have the single bank fueling in the BEF flash options.

see primary O2 location with grey wire ? Ignore the fact this is grey wire, should be black OEM, but I used the grey since the length was shorter.

[oVeRdOsE.]

for A/R smaller area, faster air speed.

Now, how will be affecting the E9x drivability, I dont know, this is only by reading and judge your preference.

On a street car I want a lower boost threshold.
On my turbo size, I dont think this will be bad for the rod, aftermarket twins can be worst, go see dyno sheet in the pinned thread.

And even if you think the torque is too agressive on low rpm, you can always tune it with jb4.

Also, technically a higher a/r for same size turbo should do more high end power (more surface area for air to travel, thus more cfm for same pressure), at this point, the N54 will be more powerful over 99% of the car I will cross on the road.

[STATIC A$TRO]

I'm running the DR kit, so I have that DR plate you are speaking of, 99.9% of all the ST engine bays I see are running either the DR turbo blanket, DR turbo blanket w/heat tape or just the Speed Tech VCB.

I tried looking for answers before but came up empty handed and ended up buying that speed Tech blanket in hopes that I could fit it along with the heat shield and blanket (I couldn't). so now I have a $250 blanket looking pretty halfway on. I've posted about this elsewhere and 1 other has said that it will more than likely end up not working out for me.

I tried to stay away from reflective tape Aswell I don't really like how it looks but ended up having to use it to wrap some wiring but might end trying to see if I can cover those a bit better. I haven't looked into the welder blanket or the modified heat shield.
as far as the exhaust manifold and DP I'm hoping the shop wrapped them correctly before they screwed us over.

I wish someone had told me about how long and tedious this journey would all be as it's supposed to be my daily, coming up on 9 months.

[oVeRdOsE.]

all ''stage 3'' tune (aka changing or adding induction system) shouldn't be on a mandatory daily.

Those kit are good, but not complete. There a lot of supported mod that you have to do, the 'while Im here' and the software (tune).

I think youtubers are a bit too positive on how this is easy. Most of them are sponsored anyway, no surprise here.

Ive started mine in august, and the car started in December. Now I'm stuck in the snow, so I can test drive it, but pretty sure Ill run into issues. However, mine was a complete divetrain swap into a E91.
I took my time, maybe 4-6 hours per weekend, not every weekend, I have kids, a house to reno, a job, friends, family... so yeah, this car couldn't be my daily.


If you already have the Doc race plate, what are you looking for more ? Pretty sure this is enough

[STATIC A$TRO]

it was an opportunity to good to pass up on. shop should've done most of the heavy lifting but ended up bending us over backwards and screwing us, over a 4–5-month period. I'm young so it's easy to put optimism into my eyesight but now it's just sitting as I try to get it all together. those supporting mods were let known to me as we progressed which was annoying, I wish they would've been let known to me at the beginning , but you live, and you learn.

as far as why idk? I really liked how 335i Carlos's looked with the metal one but saw the speed Tech carbon blanket and liked how they could both be matching so I bought it thinking it would kind of be the same thing. I asked everywhere and not getting any answers I turned to forums just recently making my acc so I can finally ask for some insight. came to the conclusion there's no space to fit all 3.

as far as getting it going i just need my catch cans, tune and waiting on a few bolts I dropped into the engine bay but never touched down... there is more but atp I'm trying to get it moving.

[STATIC A$TRO]

appreciate you for the time and input.

[oVeRdOsE.]

I learned too that those kind of ''custom job'' cars or home improvement, always have a miscommunication and at the end you get screwed up.

this is why now I'm DIY only. If I screw up, I cant be mad to anyone but me. Bonus, when you get it, you save tons of money.

[Mustafa.e92]

At first I also had that concern. Preferred that the dme had control of separate banks instead of all 6. This is true but any kit that offers dual bank 02 they will be pre turbo. To much heat they will not last. Any inline 6 with a single turbo will only have 1 primary and 1 post, unless it’s the odd one in the book. N55, B58 ect. If everything is in tip top shape. Injectors, plugs, walnut blast ect you should not have issues with a good tune. Any issues will still be apparent in a data log.
Here’s what’s worked for me for heat management for the last 2 years daily driven

- speedtech ceramic coated exhaust manifold(not even sure if this does much)
- quality turbo blanket
- dei heath sleeving for the turbo lines. (This one’s super nice must be pushed ontop of the lines before installing to turbo)
-m18 valve cover because plastic melted
-heat wrap on the downpipe
-heat sleeve on the brake,ac, ground wire
-redone wiring and heat sleeved.(by turbo)
Any heat shielding to keep turbo heat away from the valve cover in my opinion fits like shit and looks terrible. If in budget upgrade to a metal one and this is not a concern. I have the m18 cover to hide the wiring. Still had to attack it with a dremel to fit

[Mustafa.e92]

First pic is before I had the harness rerouted. I’ll see if I can find a pic with the reroute but it runs further away from the turbo now

[SlowE92]

Originally Posted by oVeRdOsE.

yes, the O2 sensors are in the exhaust manifold, so divided.

However, a lot of people suggesting going single bank. I tried to find some cons, and apparently there's none ? I was worried that if 1 bank go lean or rich, the engine will limp no matter what on a dual bank fueling.
Now if I have 1 single bank, how it will know if a bank go bad ? dont know !

Other than this question key benefit are :
- 1 primary O2 (wide band) and 1 secondary ( normal ). cheaper to replace. You keep the black wire O2s.
- Primary O2 less prone to break because of the heat. The location is after the turbo hot side on the downpipe.
- Way more easier to swap since its now accessible from the top
- less issue with JB4 or MHD
- Overall more reliable.

You have the single bank fueling in the BEF flash options.

see primary O2 location with grey wire ? Ignore the fact this is grey wire, should be black OEM, but I used the grey since the length was shorter.

Yeah thats what I was interested in was the single bank fueling. Having twice as many 02 sensors and having to monitor 2 banks was twice the headache. What about the exhaust setup? Do you have a single pipe or merge the single pipe into a Y pipe to keep the dual exhaust?

[SlowE92]

Originally Posted by Mustafa.e92

First pic is before I had the harness rerouted. I’ll see if I can find a pic with the reroute but it runs further away from the turbo now

What intake manifold are you running? Your single setup is one of the best I've seen on here hands down.