Lets talk risk factor

[langsbr]

Prove me wrong

I don't think it's a matter of right and wrong, but preference. How boring would this hobby be if EVERYONE did the exact same thing? I enjoy having the same car but different approaches to our shared goal of enhancing the car's performance.

Twins have roughly 2x the failure points vs. a single and still rely on a bad wastegate design.

Not gonna deny that - just by matter of having two turbos, two wastegates, two downpipes, etc. I think the "bad wastegate" design is beat to death. Sure an 80K mile stock turbo car will have issues, but have there really been any examples of hybrids having the issue? I'm sure Rob can give us his metrics on it.

Twins of similar output cost less vs. a single top mount of similar output. However with the new speedtech bottom mount I think it tips in the single's favor for power output & price.

While the speedtech bottom mount is pretty nice, and a great value proposition - it misses 2 of the biggest reasons people go single turbo - 1. easy service (I also never understood why servicing or replacing the turbo is such a great thing, if singles are supposed to be so much more reliable) 2. no bling factor. I would run the speedtech just because it adheres more to my motto of 'closer to stock' - no chance of the valve cover melting, etc. I'm still not a fan of pre turbo O2s though.

On a slightly related note - to the OP - if you're buddy just wants to be "fast" and beat your car and wants a 10 second car - dump this platform. Sorry, but LS is just too damn easy to make big power. You can take a Colorado, slap a junkyard 4.8 and a china turbo and run 9s at 150 on stock everything, and that's a truck. I'm excited to see Steven Clark's LS 135 setup finally run. I still think he spent too much money on things he didn't need to. I say run those 4.8 paper headgaskets and just send it!

 

[SlowE93]

Lol, thats what I told him. Buy another car ! But it is what it is, he is working with what he has. Mind you, its not that difficult to beat my car on any upgraded style turbo. At this point he is now leaning towards hybrids. He is still on the fence of engine longevity. Not turbo longevity. He just doesnt want to pop his stock, over 100k mile motor.

 

[fmorelli]

langsbr:
Prove me wrong

There is not much to prove wrong. You're right.

But BMW is not stupid. So riddle me this: why did they design a small frame turbos, low CFM head 3.0 liter twin turbo?

Filippo

 

[langsbr]

But BMW is not stupid. So riddle me this: why did they design a small frame turbos, low CFM head 3.0 liter twin turbo?

Probably the same reason Nissan put a truck motor in the 240SX in the US rather than the SR20. Muricans like their stump pulling torque! Muricans are lazy and don't like to downshift - lug that motor at 1200 rpm in 5th - yee haw. It lets them focus on giving junior some crayons in the backseat rather than have to pay attention to driving. Just look at the history of domestic cars - BIGBIG BIG V8s. Low redlines. Heck, even a stock 5.0 windsor torque begins to fall at 4000 rpms.

The stock N54 has 300ft lbs of torque from idle to 5000 rpms - perfect for us muricans to lug the motor around town. Pull to 7000 rpms? Why bother.

 

[fmorelli]

Muricans are lazy and don't like to downshift - lug that motor at 1200 rpm in 5th - yee haw.

Well ... but N54 was a world offering on BMW's main platform ...

Filippo

 

[DCook]

Just dont run 32lbs on a single and stay in it while misfiring, that tends to bend rods throwing the skirt into the wall lol

 

[tisdrew]

Well he wanted a 10 second car, LMMFAO !!! He already realized its not the best platform. He wants to beat me :smh: so I would imagine traps of close to 130. I have trapped 126.

I was going to say have him buy a f80/2 but then realized it probably made sense to consider his budget. If mexico and trap speeds are all that matter, gonna be hard to beat a LS or nitrous honda for the money. It makes it sound like he isn't the most disciplined and doesnt realize how much suspension/trans setups will cost to get most cars into the 10's.

 

[SlowE93]

I was going to say have him buy a f80/2 but then realized it probably made sense to consider his budget. If mexico and trap speeds are all that matter, gonna be hard to beat a LS or nitrous honda for the money. It makes it sound like he isn't the most disciplined and doesnt realize how much suspension/trans setups will cost to get most cars into the 10's.

As I said....youtube is where he gets all his info. If i was swappn his plugs when this conversation took place, what does that tell you ?

 

[SlowE93]

Just dont run 32lbs on a single and stay in it while misfiring, that tends to bend rods throwing the skirt into the wall lol

Lmao !

 

[tisdrew]

As I said....youtube is where he gets all his info. If i was swappn his plugs when this conversation took place, what does that tell you ?

He's never had a fast car and doesn't know what 500 horsepower is like.

 

[SlowE93]

He's never had a fast car and doesn't know what 500 horsepower is like.

He knows what its like as he has been in mine. He does NOT have mechanical skills and does not understand suspension, how engines work, compression, timing, etc. As I said...I was swappn his plugs for him. Simple job, but not simple to a guy that knows nothing about it.

 

[Torgus]

As I said....youtube is where he gets all his info. If i was swappn his plugs when this conversation took place, what does that tell you ?

That he needs to grow a pair and do his own wrenching. Plugs are so damn easy on these cars. It's like an oil change.

 

[langsbr]

It's easier since you don't even have to get dirty!

 

[Rcboosted2007]

There is no safe point.

 

[GreyNBlueE92]

Use YouTube to get him interested in how cars work and go from there...

 

[SlowE93]

Ok, update. He went pure twins. He had a question about timing vs boost. Ill see him later today and ask him exactly what he wants to know. He told me but Im not quite sure i fully understood the question at the time.

 

[SlowE93]

See, statements like this cause confusion. Its ALMOST like saying just buy the biggest turbo for a happier engine.

 

[SlowE93]

This was the question in general for this post. As I said, he went hi flow already and is dialing it in.

 

[SlowE93]

So I was reading an article about how above 25psi there is greater chance if cylinder ovaling. So how true is this ? This is the confusion. If a single turbo at 22 psi is making 650 whp, and a small twin turbo at 26 psi is at 600, according to the article, the 600 whp is more likely to oval cylinders over time.

 

[matreyia]

langsbr:

Twins have roughly 2x the failure points vs. a single and still rely on a bad wastegate design.

Twins are 10x as expensive and time consuming to service vs. a top mount turbo.

Twins are limited in output vs. the potential of a single if you take out vendor unicorn dynos(SlowE93's buddy likes Jake he specifically lists why he ditched the twins and went #singlelife it was for reliability)

Twins of similar output cost less vs. a single top mount of similar output. However with the new speedtech bottom mount I think it tips in the single's favor for power output & price.

Prove me wrong

My issue with singles is the amount of physical alterations required to the bay, the o2 sensor issues, the heat next to the coils and intake areas and the astronomical hardware prices and.... the lag vs. twins. So they will never be an option for my personal tastes. Realistically, I ain't never ever gonna even use half the amount of power upgraded twins will give me let alone singles...so it's pretty pointless to chase after HP.