[Vegasboy]

I use my BMW as a daily driver, what I love most about the 335i is the dual purpose of this car. While just cruising around town I love the luxury, smoothness of the suspension and drivability of this car. The power is so smooth and with its almost non existent turbo lag, sometimes it feels like a NA V8. In Driver Sport mode, without having to think, the transmission just always seems to know which gear I want to be in.

Then comes the fun part when you stomp on the gas this car just comes alive and can be a real beast. I truly think this is one of the best dual purpose/crossover cars I have ever driven. I'm getting older so the luxury and smoothness are more important to me than when I was in my 20's. I still find myself wanting more power though. I've done all the M3 suspension parts, still on stock sport shocks, running E50, pretty much FBO, I have inlets and charge pipe in my garage waiting for me, looking to get some custom tunning once installed.

As most of you know modding is very addictive. You always seem to crave more power. So now I'm looking at turbo options. There are some reasonable Single turbo kits i'm looking at. The On3 and JP kits. Also very interested in the new Cast twin options coming out.

My question to all you ST guys is how is the spool up and daily drivability compared to the twins? Any one have any dyno graphs with ST vs stock turbos? What is the best Turbo for street use and with a AT?

Also read on the Supra forums they are using quick spool valves, non divided manifolds, and a twin scroll turbos. The QS valve sends all the exhaust gas through one side of the turbo, essentially cutting the AR ratio in half. This makes the turbo acts like a smaller turbo until the valve opens up. This brings the spool up down 500-600 rpm but also bumps 50hp and 70 torque at 3500 rpm. But I don't see anyone trying that with the N54.

[omarmarji]

i daily my car with the specs in my sig..... fun as hell and no one on the street can mess with me...spool is surprisingly quick and drives nice and smooth

[jlcf22]

Precision Gen 2 6062 have good reviews on other platforms probably the best spool and power for AT cars their rated for 750hp

[Vegasboy]

So how much lag is there with the ST compared to stock? Really wish I could drive one first.

[ferocity02]

What's going on with the VANOS tuning? Last I read there were some noteworthy reductions in single-turbo spool with VANOS tuning.

[Sered]

Originally Posted by Vegasboy

This brings the spool up down 500-600 rpm but also bumps 50hp and 70 torque at 3500 rpm. But I don't see anyone trying that with the N54.

Generally because we aren't as laggy as Supras. My 6466g2 hits 17psi at 3300rpm in 3rd with the new vanos and spool changes

[135pats]

People freak out about spool and I don't really understand why. My 3586 hits target/full boost well before 4K RPMs, without touching VANOS tables or specifically tuning for spool.

Unless your goal is 450WTQ at 2.5K RPMs I don't see what the issue is. The car feels plenty strong down low, it's just not jumpy like a stock frame car.

[gixercho]

Closest to stockframe will be Garrett GTX/HTA3076 or PT5858, everything bigger than that will be very different to 3k rpm no matter what tuning or fuel are used.

[bigdnno98]

Originally Posted by gixercho

Closest to stockframe will be Garrett GTX/HTA3076 or PT5858, everything bigger than that will be very different to 3k rpm no matter what tuning or fuel are used.

I would love to see a log of one of those on an N54. I don't think anyone has tried it. Would have to at least be an .82 AR turbine housing. May be too much for that turbine wheel though. Would be very interesting as the GTX3076r is one of my favorite street turbos. Right behind an HTA3582r

[135pats]

Originally Posted by bigdnno98

I would love to see a log of one of those on an N54. I don't think anyone has tried it. Would have to at least be an .82 AR turbine housing. May be too much for that turbine wheel though. Would be very interesting as the GTX3076r is one of my favorite street turbos. Right behind an HTA3582r

I think Terry had an FFTEC 5858 (maybe it was a 5862) on an N54 awhile back. IIRC it spooled well, but not so well that it was a better value or performance proposition than the 62mm turbos.

I want to say it made high 500s or so.

[gixercho]

First i bought owen 3079HTA with Tial .82, but in the last moment i get 3582HTZ which is the upgraded design of the HTA. I hate myself now of that i put the bigger one instead of 3079HTA, which now sitting on shelf in my bedroom brand new. There are several GTX3076 out there, but their owners don't want to share info. The 5862 or Garrett 3576 (which is garret equivalent of the pt5862) wouldn't spool so fast because of the bigger turbine wheel.

[bigdnno98]

How does that 3582 spool? You have a log you could share with us? That's the turbo I would use if I were going ST.

[gixercho]

Not the best logs, but i don't have time now to search. 3rd gear AT trans.

[alpinedevil335]

Originally Posted by Vegasboy

So how much lag is there with the ST compared to stock? Really wish I could drive one first.

If you're ever in the L.A. area hit me up, I'll take you for a spin in my VM 6466.

[bigdnno98]

Originally Posted by gixercho

Not the best logs, but i don't have time now to search. 3rd gear AT trans.

20psi by 3,500 RPMs is pretty good. I'd be happy with that as a ST guy.

[gixercho]

Wow yeah it is very good and i have even better logs with may be 23psi at 3500 3rd gear, but the problem is the range between 1.5k-3k rpms. No matter what people says big turbo is big turbo and it needs rpms to spool. Yeah the tuning helps alot, but physics is physics. My turbos is one of the best and fast spooling turbos for it size on the market and i feel the lag to 2.8-3k rpms compared to stock twins and stage1 hybrids that i had before the ST kit.

[bigdnno98]

Originally Posted by gixercho

Wow yeah it is very good and i have even better logs with may be 23psi at 3500 3rd gear, but the problem is the range between 1.5k-3k rpms. No matter what people says big turbo is big turbo and it needs rpms to spool. Yeah the tuning helps alot, but physics is physics. My turbos is one of the best and fast spooling turbos for it size on the market and i feel the lag to 2.8-3k rpms compared to stock twins and stage1 hybrids that i had before the ST kit.

Yup. There are always tradeoffs. Your trading some low end torque for better overall powerband and better reliability with the DBB Turbo. Great choice.

[Bme30]

I love the way my single turbo drives! I went exactly what you are going through about a year and a half ago. All I can say is im SO GLAD I WENT SINGLE!!!! It's a blast and now I have like 350-400 wheel more hp than before! ��

[Bme30]

[ATTACH][/ATTACH]

Stock frames with e20ish and meth (procede tuned)

[pysical]

I have RB turbos and hit 20 psi at 3500rpm.

[Bme30]

6466 gen 2

[bigdnno98]

Some people can't stomach the lag. They want 600HP but they also want stock like spool. It's just not happening. Maybe if you spend $8-9k on the VTT Stage 3 kit with twin GTX2876r but even then, you're spending an additional $3-4K and gaining maybe 1k RPMs in spool. They're still going to spool slower than the tiny stock snails. I know I hated hitting full boost (35psi) in my EVO at 5k. It sucks driving around town like that. So you have to really decide on realistic goals and shoot for that. I've been pretty impressed with most of the single turbo n54s and how they spool. Very acceptable to me.

[natedog7700]

Originally Posted by bigdnno98

Some people can't stomach the lag. They want 600HP but they also want stock like spool. It's just not happening. Maybe if you spend $8-9k on the VTT Stage 3 kit with twin GTX2876r but even then, you're spending an additional $3-4K and gaining maybe 1k RPMs in spool. They're still going to spool slower than the tiny stock snails. I know I hated hitting full boost (35psi) in my EVO at 5k. It sucks driving around town like that. So you have to really decide on realistic goals and shoot for that. I've been pretty impressed with most of the single turbo n54s and how they spool. Very acceptable to me.

Lag isnt bad with my car and im at 600hp (crank). Thats with 93 octane too.

[Tony@VargasTurboTech]

Originally Posted by bigdnno98

Some people can't stomach the lag. They want 600HP but they also want stock like spool. It's just not happening.

It is possible if you use the right turbos. I mean we are making 730+WHP, and the car is spooling faster than stock turbos on the street. We never posted any GC street logs previously, so here is one just for information sake. Street pull done the day before the 2/28 Shift Sector, target was 28 psi or so. 4th gear started the pull at 2K.

15 psi around 2500 RPM
20 psi around 2700 RPM
25 psi around 2850 RPM

At that point we are near target so boost just flattens out instead of continuing spool, with say a 35 psi target, you would see 30 psi before 3000RPM. If you read any other spool info on the GC it is based of dyno spools logs, and apples to oranges as we never posted a street log.

http://www.***********/u/vargasturbot...3&zoom=122-181

[bigdnno98]

Originally Posted by VargasTurboTech

It is possible if you use the right turbos. I mean we are making 730+WHP, and the car is spooling faster than stock turbos on the street. We never posted any GC street logs previously, so here is one just for information sake. Street pull done the day before the 2/28 Shift Sector, target was 28 psi or so. 4th gear started the pull at 2K.

15 psi around 2500 RPM
20 psi around 2700 RPM
25 psi around 2850 RPM

At that point we are near target so boost just flattens out instead of continuing spool, with say a 35 psi target, you would see 30 psi before 3000RPM. If you read any other spool info on the GC it is based of dyno spools logs, and apples to oranges as we never posted a street log.

http://www.***********/u/vargasturbot...3&zoom=122-181

There's no doubt, those spool very fast. That's insane. The question lately has been about the stock frame reliability vs a DBB single, being as the single kits are coming down in price a lot. People are looking more and more for reliability lately. I know I sure as hell wouldn't be putting more than one set of upgraded stock frames on a car. If they had to get taken off for repairs, they're not going back on. It would be DBB ST time.

Time will tell how these GCs hold up, but that spool is pretty amazing.