Holset/BW Turbos versus ball-bearing Turbos v.transient response

[RMeadows]

I keep reading that the Holset and Borg Warner Turbos have amazing initial spool-up characteristics for their size but no one ever mentions transient response. Do these turbos compare to a DBB turbo in that area? In the market for a 450whp capable turbo that will have the best transient response as possible, so i'm open to suggestions. Right now I'm pretty set on an S256 pending the responses I get in this thread....

 

[mtshores]

hey not sure about transient response, but i have a BW S258 so i thought i could tell you what i know. I have a stock 2.0 with 272 cams and meth. i made 377 at 23psi and i can tell you it would easily do 450. I would have made more but i have a stock headgasket and thought 23 was pushing enough . the turbo i has is completely spooled by 4500rpms which is a bit laggy but im going to go to a 2.3 later and with the extra displacement should spool better (also ive had a bit of an exhaust leak due to manifold gasket i fixed that now and its spooling even quicker). I purchased this turbo because i was told it is more effecient than a gt35 BB and it was more durable. In addition these turbos can be rebuilt cheaper than the BB turbos just incase something goes wrong. One final thing my 258 sounds nasty .

 

[RMeadows]

Appreciate the input. So when you shift gears does the car instantly get back into boost or does it take a split second to spool back up? That's my main concern. I hate the way my 16g falls on its face in between gears

 

[Slippi84]

Appreciate the input. So when you shift gears does the car instantly get back into boost or does it take a split second to spool back up? That's my main concern. I hate the way my 16g falls on its face in between gears

If you think your 16g has bad transient response you are living in your own little world. Any of the borg turbo's even the s256 will have WORSE transient response than a 16g unless your 16g is shot or you clipped the hell out of it or something. A 16g is at full boost around like 3800 at the latest and so when you shift your already suposed to eb in full boost for the most part. If your not you have another problem.

 

[jwcardy]

If your not you have another problem.

Thats kinda what i was thinking. Have you boost leak tested your car lately? You would be suprised what you would find.
-wes

 

[RMeadows]

If you think your 16g has bad transient response you are living in your own little world. Any of the borg turbo's even the s256 will have WORSE transient response than a 16g unless your 16g is shot or you clipped the hell out of it or something. A 16g is at full boost around like 3800 at the latest and so when you shift your already suposed to eb in full boost for the most part. If your not you have another problem.

Well I did have some boost leaks that I fixed a few months ago and one that I can't fix which is right at the J-Pipe(pretty common). It's very small though. I see full boost around 3200-3400 so I'm assuming everything is just fine. When I shift i'm at full boost obviously, but when I get into the next gear there is a split second lag where the turbo has to spool back up, it doesn't stay spooled in between gears and i'm pretty most non-bb turbos don't....?

 

[blownturbotsi]

That's what NLTS is for.

 

[Slippi84]

Well I did have some boost leaks that I fixed a few months ago and one that I can't fix which is right at the J-Pipe(pretty common). It's very small though. I see full boost around 3200-3400 so I'm assuming everything is just fine. When I shift i'm at full boost obviously, but when I get into the next gear there is a split second lag where the turbo has to spool back up, it doesn't stay spooled in between gears and i'm pretty most non-bb turbos don't....?

As dumb as this sounds your 50mm tial may be doing too good of a job that or maybe your line to the bov is being T'd into or off of if you get what I'm saying. That bov will relieve pressure from just about anything you can throw at it and it may just be overkill for you and causing you to relieve too much pressure in between shifts. Now that's still a shot in the dark but you still will not see any better results with any othe rturbo besides maybe a 14b and t25. A BB turbo will not fix what you feel.

 

[blownturbotsi]

Actually a BB turbo will keep spinning for quite a bit longer than a standard center turbo. That leads me to believe that he would have better response between shifts, even on a bigger turbo.

 

[RMeadows]

That's what NLTS is for.

My stock trans is already in iffy shape, i'd rather not tempt fate

 

[RMeadows]

As dumb as this sounds your 50mm tial may be doing too good of a job that or maybe your line to the bov is being T'd into or off of if you get what I'm saying. That bov will relieve pressure from just about anything you can throw at it and it may just be overkill for you and causing you to relieve too much pressure in between shifts. Now that's still a shot in the dark but you still will not see any better results with any othe rturbo besides maybe a 14b and t25. A BB turbo will not fix what you feel.

Actually I DO have my BOV line T'd. Wonder if that really could be it...

Could it maybe be spring pressure related? Heh. This actually brings me to another problem i've always had with the TIAL. At steady throttle when boost is building up if I don't go WOT the BOV opens and starts relieving pressure. For example, say I'm at 40% throttle and getting into boost, if I don't continue to get into it and go WOT and just keep the throttle steady as it builds towards full boost the BOV will blow open. Not sure if that's related to the spring pressure or the fact that I have the vacuum line T'd off though....

 

[Slippi84]

Actually a BB turbo will keep spinning for quite a bit longer than a standard center turbo. That leads me to believe that he would have better response between shifts, even on a bigger turbo.

Unless you granny shift the difference at rpms where you would be shifting that wouldn't be a night and day. My last turbo was a gt14(duall BB) so I speak first hand when it comes to ball bearing tech. and transient response.

 

[Slippi84]

Actually I DO have my BOV line T'd. Wonder if that really could be it...

Could it maybe be spring pressure related? Heh. This actually brings me to another problem i've always had with the TIAL. At steady throttle when boost is building up if I don't go WOT the BOV opens and starts relieving pressure. For example, say I'm at 40% throttle and getting into boost, if I don't continue to get into it and go WOT and just keep the throttle steady as it builds towards full boost the BOV will blow open. Not sure if that's related to the spring pressure or the fact that I have the vacuum line T'd off though....

I would run a dedicated line to the bov and check the spring because the thinsg your saying would cause slower boost response especially between shifts when the bov operation is most important obviously.

 

[RMeadows]

I would run a dedicated line to the bov and check the spring because the thinsg your saying would cause slower boost response especially between shifts when the bov operation is most important obviously.

Got it. Thanks.

tutorial anywhere? I only have two vacuum lines in that area and 3 nipples I need to hook up. Wastegate, BOV, Boost Controller.

 

[Slippi84]

Got it. Thanks.

tutorial anywhere? I only have two vacuum lines in that area and 3 nipples I need to hook up. Wastegate, BOV, Boost Controller.

Boost controller: Wastegate to a nipple on either compressor housing or the j pipe

Bov: Line straight to intake manifold or tb

Wastegate(if you have one with two vaccum nipples): to the intake manifold or tb

 

[dsm-onster]

From my experience with the hx35/h1c holset turbo, it has the same transient response as the small 16g. Same initial spool time, too.