Anyone running a GT45R on their STREET 13B ? Got this friend whose putting together a great setup , the motor will be half bridged etc. He seems hell bent on slapping on a 45 with a T4 , 1.15 a/r turbine . I'm telling him a GT4202 would be a better choice and it costs a lot less too , but he insists that the boost response would be the same but with more power , is this true ? Anyone have experience on this ?

 

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I'll take a stab in the dark from what I've read about oversized turbo's with small engines.

with a proper sized WG and pop-off valve set-up he can probably achieve what he wants. Keep the WG closed as much as possible; by venting boost thru the pop off valve.

anytime a WG opens energy is being lost/redirected in the area that helps spool...so if you run a smaller WG with a heavy spring, and regulate boost with the POV, exhaust engery will be forced thru the turbine housing...until the POV can't regulate anymore (probably extremely high rpms).

IIRC, you will want to set the POV 1-2psi lower than your WG spring...this means your WG will be a the point of cracking open at full boost. You can probably get away with using a simple (but good) MBC for tuning and no boost controller once tuned. I'm sure tuning is a bitch with this type of set-up, swaping springs and such, but once complete...I bet the 45 can perform like a 42 with more power.

 

won't the pop-off valve make the turbo work harder?

 

less air in [the motor] = less air out. In other words the turbo won't be chasing its tail

with a turbo the size we are talking about...I'm sure the "work load" would be fine.

 

[QUOTE=dubulup]I'll take a stab in the dark from what I've read about oversized turbo's with small engines.

with a proper sized WG and pop-off valve set-up he can probably achieve what he wants. Keep the WG closed as much as possible; by venting boost thru the pop off valve.

anytime a WG opens energy is being lost/redirected in the area that helps spool...so if you run a smaller WG with a heavy spring, and regulate boost with the POV, exhaust engery will be forced thru the turbine housing...until the POV can't regulate anymore (probably extremely high rpms).

IIRC, you will want to set the POV 1-2psi lower than your WG spring...this means your WG will be a the point of cracking open at full boost. You can probably get away with using a simple (but good) MBC for tuning and no boost controller once tuned. I'm sure tuning is a bitch with this type of set-up, swaping springs and such, but once complete...I bet the 45 can perform like a 42 with more power.[/QUOT

He plans on using a Tial V60 wastegate and BOV , boost will be controlled by the ECU , it will be set up to increase as he moves through the gears.

 

I never understood why people want a the large turbocharger with a large wastegate

you chose a large turbo to run loads of boost which takes loads of exhaust energy...you crack open a large wastegate and loads of exhaust gas leaves the manifold.

the only reason to run a large wastegate would be to limit boost to something not worth while to lug around a heavy turbo in your engine bay for shows.

just my humble opinion...of course I'm not a huge power guy, or a show guy so

 

how much boost is he planning on running? I never got the reasoning behind getting a huge turbo and only pushing 12psi through it. I like big turbos don't get me wrong but if your not using it for what it was designed for then why bother? Now if he is running a crap load of boost through it then great but he wouldn't need a huge wastegate then.

 

Up to 20-25 psi on pump gas with WI and 30+ with race gas and WI.

 

Anyone else ? and to answer your question dubulup , he has an integrated WI system too , if there is a fault he wants the boost to drop completely off to a safe level , he also wants to leave the line at low boost and end at high boost for traction issues.

 

GT45R will spool slower. Its 12 blade turbine wheel is larger then the S-trim and also less efficient by design.

 

Everyone who is serious here uses a GT45R, nobody wasts their time with the GT42R as its turbine wheel is TOO SMALL.

The fastest 13B for many years ran a GT45R
The fastet 12A runs a GT45R and makes over 700rwhp on our dyno systems @ around 30psi boost.

 

Again , alot of people making unsubstantiated claims about things they don't know ! I have personnaly seen a street ported motor hit 24psi by 5000rpm on a journal bearing GT45 witha a 1.32 a/r T6 exhaust housing ! it made 504 RWHP . So why would a half bridged , ball bearing 1.15a/r turbo be laggy ?

"Everyone who is serious here uses a GT45R, nobody wasts their time with the GT42R as its turbine wheel is TOO SMALL.

The fastest 13B for many years ran a GT45R
The fastet 12A runs a GT45R and makes over 700rwhp on our dyno systems @ around 30psi boost."

My thoughts exactly , we are even looking at the GT47 which uses an even bigger turbine wheel with the same compressor !

 

have you found any good prices?

 

GT45R for $2500 at Evans Tuning , BEST PRICE ON THE NET! , heres a link http://site.mawebcenters.com/evanstu...l?catId=248109

 

I think it was just Turbodriven

 

OK, so I think we've established that the GT45R could be made to work well on a 13B that has been prepared properly , but would the GT47 be better because of the larger turbine wheel or would this unit be too much of a "good thing" ?
Here are some sepcs on the GT47 , let me know what U guys think !

Ball Bearing Garrett GT4708R (aka GT4780-R) . Capable of close to 1200HP!

Compressor wheel diameter is 108mm exd. / 80.8mm ind. (56trim) Compressor housing is .69 A/R has a 6" inlet and 3.5" outlet slip on connection. Turbine housing uses a T4 divided inlet and 4" V-band
outlet. Available Turbine housing A/R, 1.01, 1.15, 1.28, and 1.44

Turbine
-Wheel: 92.7mm w/ 82 trim
-Housing: 1.01, 1.15, 1.28, 1.44 A/R
-Maps

Compressor
-Wheel: 108.0mm exd./80.7mm ind w/ 56 trim
-Housing: 0.69 A/R
-Maps

 

" integrated WI system too , if there is a fault he wants the boost to drop completely off to a safe level "

whether you run water or alcohol or a combo i seriously doubt that if, for example, your pump blows a fuse and your right foot is on the floor and you have tuned up for AI, saving your motor w a signal to the turbo WG is going to do the job.

the wastegate is a mechanical event. guess how many combustion cycles will ocurr before the boost actually drops?

IMO, when knock ocurrs due to an AI malfunction, electricity traveling at the speed of light to alter ignition advance may be the primary save.

John, of J&S fame, maintains that his ignition retard when triggered ocurrs on the next rotor combustion.

i realize this is off topic but did want to comment as it is a life and death engine issue.

howard

 

Not sure if you're referring to my system Howard but , If there is a fault , the boost solenoid is de-energized , ignition is retarded and fuel is dumped !

 

i wasn't referring to anything but the single statement in the post which indicated that the wastegate was being used as the safeguard. your setup sounds excellent.

hc

 

Anyone ?