Same size turbos...

[smidge]

don't care about flanges and rotation (that can all be fixed)

just about matching it to the engine and not turning it into a lag monster

What OTHER turbos would be a similar size and flow rate to the stock ST turbo?

 

[Baz]

don't care about flanges and rotation (that can all be fixed)

just about matching it to the engine and not turning it into a lag monster

What OTHER turbos would be a similar size and flow rate to the stock ST turbo?

I'm not too up to date with turbo sizing,whats up with yours?

 

[Snikty]

I've not had anything ok'd with my mechanic in regards to turbo upgrades yet but I'm thinking either GT2554R or GT2854R. They are the smaller of the GT25 n GT28 series. Look like they should be a suitable match in regards to amount of psi and end results for hp.

 

[smidge]

its only gotta do 15psi with as little lag as possible on a 930cc.. those are the rules

 

[Snikty]

GT25 then. Faster spool than the GT28 and I dont know that many of the small category turbos would withstand the potential hp of these engines if running 15+psi. Would be safer with a medium size turbo imo.

 

[Baz]

You the Ht10 will do 15psi all day long?

 

[smidge]

yeah but i'd rather adapt to a (possibly newer) style turbo that i can drive 5 mins away and get a replacement from the jap shop than a rare old one!

 

[Snikty]

You can still buy recon kits for the ht10.

 

[smidge]

From Nissan? Rubber door seals, that are $35 for local cars, are $700 ! need i say more?

 

[Baz]

From Nissan? Rubber door seals, that are $35 for local cars, are $700 ! need i say more?

Google , i got a kit before with my first st

 

[Retepetsir]

For the standard 110ish bhp? Garrett GT15? Suited for 100-200bhp setups and very quick spool time.

 

[Snikty]

From Nissan? Rubber door seals, that are $35 for local cars, are $700 ! need i say more?

Yeah as baz said, google. You dont have to get em from nissan. Lots of companies out there that design their own rebuild kits and ht10s are still a popular model turbo...people still use em on rx7s.

For the standard 110ish bhp? Garrett GT15? Suited for 100-200bhp setups and very quick spool time.

Are they good for running 15psi all day?? I've had a brief look at the gt15, 20 and 22 and they appear to be set up to run around 9psi in most cases. Would be good if they were suitable for running 15psi too coz as you said, nice quick spool on em.

 

[Snikty]

Just did some research and a GT15 will remain good up to about 16psi but any more can make it unstable, so would be a viable option.

However, going by A/R figures the HT10 is rated at 0.83 apparently and the smallest garrett turbo that's close to that is a gt2554 at 0.80, gt2854s are also 0.80

 

[Ed]

GT1548, 200bhp rated and will do 20odd psi all day long (more in fact and still remain in its efficiency envelope).

The A/R is high on the HT10 that's one of the reasons it responds so slowly. The turbo on my ST is rated to 320bhp and has a boost threshold only 1500 higher than the stock HT10 (in use - on paper would suggest otherwise)

Ed

 

[Baz]

Can you explain the graph Ed?I might aswell be looking at a brick wall

 

[Ed]

◊ Mass Flow Rate

• Mass Flow Rate is the mass of air flowing through a compressor (and engine!) over a given period of time and is commonly expressed as lb/min (pounds per minute). Mass flow can be physically measured, but in many cases it is sufficient to estimate the mass flow for choosing the proper turbo.
• Many people use Volumetric Flow Rate (expressed in cubic feet per minute, CFM or ft3/min) instead of mass flow rate. Volumetric flow rate can be converted to mass flow by multiplying by the air density. Air density at sea level is 0.076lb/ft3
• What is my mass flow rate? As a very general rule, turbocharged gasoline engines will generate 9.5-10.5 horsepower (as measured at the flywheel) for each lb/min of airflow. So, an engine with a target peak horsepower of 400 Hp will require 36-44 lb/min of airflow to achieve that target. This is just a rough first approximation to help narrow the turbo selection options.

◊ Surge Line

• Surge is the left hand boundary of the compressor map. Operation to the left of this line represents a region of flow instability. This region is characterized by mild flutter to wildly fluctuating boost and “barking” from the compressor. Continued operation within this region can lead to premature turbo failure due to heavy thrust loading.
• Surge is most commonly experienced when one of two situations exist. The first and most damaging is surge under load. It can be an indication that your compressor is too large. Surge is also commonly experienced when the throttle is quickly closed after boosting. This occurs because mass flow is drastically reduced as the throttle is closed, but the turbo is still spinning and generating boost. This immediately drives the operating point to the far left of the compressor map, right into surge.
  
  Surge will decay once the turbo speed finally slows enough to reduce the boost and move the operating point back into the stable region. This situation is commonly addressed by using a Blow-Off Valves (BOV) or bypass valve. A BOV functions to vent intake pressure to atmosphere so that the mass flow ramps down smoothly, keeping the compressor out of surge. In the case of a recirculating bypass valve, the airflow is recirculated back to the compressor inlet.

◊ The Choke Line is the right hand boundary of the compressor map. For Garrett maps, the choke line is typically defined by the point where the efficiency drops below 58%. In addition to the rapid drop of compressor efficiency past this point, the turbo speed will also be approaching or exceeding the allowable limit. If your actual or predicted operation is beyond this limit, a larger compressor is necessary.
◊ Turbo Speed Lines are lines of constant turbo speed. Turbo speed for points between these lines can be estimated by interpolation. As turbo speed increases, the pressure ratio increases and/or mass flow increases. As indicated above in the choke line description, the turbo speed lines are very close together at the far right edge of the map. Once a compressor is operating past the choke limit, turbo speed increases very quickly and a turbo over-speed condition is very likely.
◊ Efficiency Islands are concentric regions on the maps that represent the compressor efficiency at any point on the map. The smallest island near the center of the map is the highest or peak efficiency island. As the rings move out from there, the efficiency drops by the indicated amount until the surge and choke limits are reached.

You need to read this:

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech102.html

and this:

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html

 

[Baz]

Thank you very much ,gentleman(Y)

http://www.turbobygarrett.com/turbob...o_tech103.html

Mind boggling stuff there!:suspect:

 

[Ed]

It can appear heavy at first, but its essential in understanding what turbo is suitable for a given application, it will at least show potential problems before you have even assembled anything.