Single Turbo or Upgraded Twins (Cost Analysis)

[N54STYE92]

This topic has probably been beaten into the ground, but since I can't find any recent conversation on it......


I'm currently saving for upgraded turbo's for my 335i. The problem, aside from deciding on whether I should go single or upgraded twins is cost. I'm pretty sold on going twins at this point, maybe Pure or MMP based on what I keep hearing about them, but I am not yet 100% sold.

There are a lot of good reasons to go single and a lot of reasons not to.. I'm still a bit of a newbie when it comes to the aftermarket turbo scene so I am seeking as much knowledge as I can, preferably from people who have actual experience. That said, the biggest factor for me will be cost.. I've heard that going the single route can cost as much as $13k with labor and going upgraded twins can go up to $5k+.

What should I anticipate for the total upgrade cost for both single as well as twin upgrade(s), to include the average labor cost that I should expect- I know that every where is different.

Thanks in advance!!

-09 E92 N54 M/T
-Not Daily Driven

 

[doublespaces]

Good subject, as I think the decision has gotten muddied lately with the lower cost of these new cast manifold options like the VTTS2+. Its getting harder and harder to justify going ST if you want less than 700.

You have addressed the elephant in the room up front: cost. If you are cost sensitive, I personally would recommend you stick to a twin option. My single turbo vendors obviously won't like that, but truth is, you're better off buying something that you can comfortably fit into your budget, this way you aren't cutting corners and pinching pennies later on. You can ensure you buy high quality products from reputable vendors and you actually have options to choose from, rather than going straight for the cheapest price.

Very few people who have gone ST(or any other big modification) are admitting they have found the bottom of their wallets and sometimes they are in denial over the matter. Some people can tackle these projects on a lean budget and come out with a minimal expenditure. I'm not one of those people as I tend to buy everything that looks good in the quality/value department. I hate doing labor twice and struggle with not upgrading something that I've already pulled out of the car. Putting a stock part that has an upgrade back INTO the car, kind of hurts my OCD.

So if you want my vote, go for a cast twin option, you'll be back on the road running smoothly sooner, IMO. If you feel like you can absorb a few unexpected expenses, wouldn't mind hitting 700+ on the dyno or airport roll racing event, then go with a ST. Hope that helps, I also added a poll.

 

[08_335i]

There is so many different views on this. There is cost effective ways of doing ST upgrade, but you have to be inclined to do DIY. I bought a manifold, downpipe, and dump tubes from a vendor and gathered everything else myself. Also installed it myself, this made my ST setup very cheap to do. There are some pretty cool Twin upgrades that have surfaced recently from GC's, to MMP, to the new VTTS2+, and of course there is always the tride and true Pure. I will say that since going ST, I've never looked back at twins, and would never ever go back to them. Yes, someof the newer upgraded ones can make some seriously mean power, but they make too much low end TQ for my liking. Everyone says unless you plan on going 700+hp stay twins, and I highly disagree. I run a 5862, and on a very conservative pump map I run around 500rwhp with 18-20psi. With an E30-E40 mix I run about 27-29psi (not sure on power output here yet as I haven't dyno'd it yet.) but the car is so much more enjoyable to "get on it" then twins were. And also with the new XHP tranny flash, driving in D mode with a ST setup feels like it came from the factory with a ST on it. Everyone is going to have their own opinion on this subject, it's more based on what you want.

 

[doublespaces]

You are a bit of an anomaly from the cost perspective though, very few people will DIY anything like this, and OP is already talking labor so that counts him out. Its just hard, from a cost perspective, to justify the single turbo, even with an appropriately sized turbo largely because you are replacing more things. Whenever you replace a lot of stuff, cost will be higher. So while I'm also partial to the single setup for a variety of reasons, I can't help but recommend people in this situation to go with twins. They haven't even been hit with a lot of the costs of things they'll want like LSD, flexfuel, supporting suspension, broken parts, etc. And that is basically the recipe for making cheap mother f*ckers.

 

[08_335i]

If cost is the main thing, then obviously twins are definitely the no brainer option.

 

[Steven@ClarkPerformanceFab]

Solely from my perspective I can give you my opinion on upgraded twins from a cost perspective. I'm running MMP stage 3s that I was able to snag in the group buy for $3100 including bearing treatment, outlets, install kit, and ceramic coating. I already had inlets that I was able to snag brand new from one of the facebook groups for $200. I'm currently in the 600 whp/tq range and plan to go into the 700s so I went with an MFactory twin disc which was $1480. Also got the MFactory LSD in the group buy for right around $1900 shipped. So regardless of which setup you go with you will be having to upgrade at a minimum the clutch/flywheel and its a good idea to do the differential as well. If all you are planning to run is 500-600 HP you could get away with a stage 2 LPFP which runs between $300-380ish. Anything over 600 on single or twins and you are looking at a stage 3 LPFP ($700ish) and port injection ($1200-2000ish with fuel lines, rail, injectors, and controller). You can get used downpipes, intercooler, and chargepipe for relatively cheap as well. I wont speak on a single turbo cost much because I haven't done one first hand yet but shopping around the initial parts cost for a single kit starts around $3000 for a journal bearing and can easily get into the $5-6000 range for a good fitment ball bearing kit. There are a ton of threads out there with info and DIYs to do the build yourself depending on how mechanically inclined you are. Hopefully I have given a bit of good info and not just rambled a bunch of useless things.

 

[langsbr]

Another thing to consider is bling - the single turbo will obviously stick out more with the hood popped. If you like the showy nature, then that is something to consider.

Also, many regular indy shops would probably install a set of hybrids or even GCs since they are stock location, yet decline to install an ST kit on the basis of being too custom.

In my many different experiences of vehicle ownership, I have found that the further you get from OEM style items, the more compromised the vehicle becomes. This had me stick with twins and I went MMP. I'll also not use PI, but would rather use the single or double barrel shotgun. I'm hesitant to run the double barrel since it still requires and AIC, but I need to read up more on its operation. If only there were more people using it!

 

[User Name]

I've had upgraded twins for 2 years and they are showing signs of imminent failure (shaft play, light scoring). If I had to do it all over again I would go single because the downtime and cost of repairing one turbo is much less than upgraded twins.

 

[Steven@ClarkPerformanceFab]

Not to get off topic, but when discussing supplemental fueling, specifically the VTT single and double barrel shotgun, the reason I have gathered most people stay away from this option is the added load it puts on the injectors and that the fuel flow volume of the pump doesn't increase. This system just uses the overdrive pulley to push the stock pump harder than it is designed to run which in theory is going to lead to early HPFP failure. When the PI rails initially came out a couple years ago the thing that scared most people was that cylinder 1 would misfire in high boost and kill the engines. That was determined to be due to a poor injector angle on that cylinder causing the fuel to spray against the intake runner instead of getting sucked into the combustion chamber which in turn caused the cylinder to run lean and misfire. Since then companies (specifically Fuel It!) have angled the cylinder 1 injector to prevent this from happening and the controllers like AIC6 and BMS have made it "simple" to control fuel flow and try to prevent fuel from spraying in a misfired cylinder. But I have no experience with this personally besides anecdotal evidence from other people who I've discussed their system failures with and reading threads.

Another thing to consider is bling - the single turbo will obviously stick out more with the hood popped. If you like the showy nature, then that is something to consider.

Also, many regular indy shops would probably install a set of hybrids or even GCs since they are stock location, yet decline to install an ST kit on the basis of being too custom.

In my many different experiences of vehicle ownership, I have found that the further you get from OEM style items, the more compromised the vehicle becomes. This had me stick with twins and I went MMP. I'll also not use PI, but would rather use the single or double barrel shotgun. I'm hesitant to run the double barrel since it still requires and AIC, but I need to read up more on its operation. If only there were more people using it!

 

[Steven@ClarkPerformanceFab]

I've had upgraded twins for 2 years and they are showing signs of imminent failure (shaft play, light scoring). If I had to do it all over again I would go single because the downtime and cost of repairing one turbo is much less than upgraded twins.

Not to call anybody out, but what brand turbos are you running?

 

[doublespaces]

Not to call anybody out, but what brand turbos are you running?

The list of existing companies making twin turbos for over 2 years is short

 

[Torgus]

Things to consider:

Reliability: two vs 1, also are you pushing it to the bleeding edge on or even off the compressor map or using it well with the turbo's 'comfort zone'

Fuel: roughly only 20% of our country has access to E85. If you are on pump a single will generally make more powah than twins.

Engine: low end tq is what kills the N54, having the power come on later in the rpm range is a better thing. a ST has this effect by nature. Less stress longer engine life.

All that said, I believe the lower cost of the twin upgrade is why it is more popular vs a ST. If reliable single kits were the same price as twin upgrades I think you would see more STs. Since they are not, unless you consider JP Works, more twins are sold.

 

[The Convert]

Not to get off topic, but when discussing supplemental fueling, specifically the VTT single and double barrel shotgun, the reason I have gathered most people stay away from this option is the added load it puts on the injectors and that the fuel flow volume of the pump doesn't increase. This system just uses the overdrive pulley to push the stock pump harder than it is designed to run which in theory is going to lead to early HPFP failure. When the PI rails initially came out a couple years ago the thing that scared most people was that cylinder 1 would misfire in high boost and kill the engines. That was determined to be due to a poor injector angle on that cylinder causing the fuel to spray against the intake runner instead of getting sucked into the combustion chamber which in turn caused the cylinder to run lean and misfire. Since then companies (specifically Fuel It!) have angled the cylinder 1 injector to prevent this from happening and the controllers like AIC6 and BMS have made it "simple" to control fuel flow and try to prevent fuel from spraying in a misfired cylinder. But I have no experience with this personally besides anecdotal evidence from other people who I've discussed their system failures with and reading threads.

I don't recall anyone having a motor blow from the off center cylinder one PI injector. Who had this failure?

 

[JSR1256]

Twins if you wanna keep your drivability

 

[doublespaces]

Twins if you wanna keep your drivability

What turbo and fuel do you run?

 

[Bmwfixerguy1]

Good subject, as I think the decision has gotten muddied lately with the lower cost of these new cast manifold options like the VTTS2+. Its getting harder and harder to justify going ST if you want less than 700.

You have addressed the elephant in the room up front: cost. If you are cost sensitive, I personally would recommend you stick to a twin option. My single turbo vendors obviously won't like that, but truth is, you're better off buying something that you can comfortably fit into your budget, this way you aren't cutting corners and pinching pennies later on. You can ensure you buy high quality products from reputable vendors and you actually have options to choose from, rather than going straight for the cheapest price.

Very few people who have gone ST(or any other big modification) are admitting they have found the bottom of their wallets and sometimes they are in denial over the matter. Some people can tackle these projects on a lean budget and come out with a minimal expenditure. I'm not one of those people as I tend to buy everything that looks good in the quality/value department. I hate doing labor twice and struggle with not upgrading something that I've already pulled out of the car. Putting a stock part that has an upgrade back INTO the car, kind of hurts my OCD.

So if you want my vote, go for a cast twin option, you'll be back on the road running smoothly sooner, IMO. If you feel like you can absorb a few unexpected expenses, wouldn't mind hitting 700+ on the dyno or airport roll racing event, then go with a ST. Hope that helps, I also added a poll.

I can't agree with what he said more! I have pure stage 2 high flows and and they are about 3k turbos.. Very good track record as well.. I think what Tony and VTT are doing though is just awesome.. I like the way his brain works and the products he sells
With the new vtt options out you can do very high HP, reliably and affordably as well! This bomb he just dropped is gonna get some vendors back peddling for damn sure

 

[Steven@ClarkPerformanceFab]

I don't recall anyone having a motor blow from the off center cylinder one PI injector. Who had this failure?

AJ

 

[R.G.]

As much as I hate to say it, Torgus is...correct on all fronts. (kidding bud)


The driveability guy - Please keep parroting of shit you know nothing about over at e90post.

 

[Mellow Yellow]

Not sure where you got the numbers for of $13k vs $5k. I ran the MMP stage 3s and now I have a 6266 single turbo kit. I installed both and found the single much easier to deal with. Plus you can sell your cores and other extra stuff that twin specific. Like someone else mentioned, it depends on your goals. Remember that making 700whp plus on the twins is running them at max efficiency. A single, depending on the size, won't be struggling. Higher strain will lead to quicker failure. So if you want reliability, go single. I prefer it so far. You should really learn to do work yourself if you have a space to do something. Saving on labor cost is amazing. You can get some many more extra parts

Edit: my drivability is perfectly fine as well with both the single and twins. The twins is like driving almost like twinscrew supercharged v8 where the single is obviously a turbo car.

 

[The Convert]

AJ

So....one person? How did they nail down that the cylinder one injector pointing directly at one of two valves, instead of the divider between the two valves, caused a lean cylinder and engine failure?