what if i used a .68 housing?
08-11-05, 04:04 AM
#1
what if i used a .68 housing?
i cant seem to find a decent deal on a .81 p-trim turbine housing for my T4... how HORRIBLE would it be if i used a.68? i have medium sized exhaust ports with decently sized intake porting (kahren templates)
right now i have a t04b vtrim compressor, 1.15 a/r ptrim tangential turbine and i'm spooling it by about 5000rpms (yeah, i got a good deal on the turbo ok..)
how horrible would it be if i used a .68 like this?http://cgi.ebay.com/ebaymotors/Turbo...temZ7992479612
i want to autocross my car and this would be insta-spool... but exactly how bad would it choke my engine up top? i dont have any crazy half-bridge or bridgeporting, but medium sized quality ports that arent all top end... where would the powerband be on a .68 T4 on a ported rotary???
i'd really like some input on this; the 115 housing is driving me crazy.
right now i have a t04b vtrim compressor, 1.15 a/r ptrim tangential turbine and i'm spooling it by about 5000rpms (yeah, i got a good deal on the turbo ok..)
how horrible would it be if i used a .68 like this?http://cgi.ebay.com/ebaymotors/Turbo...temZ7992479612
i want to autocross my car and this would be insta-spool... but exactly how bad would it choke my engine up top? i dont have any crazy half-bridge or bridgeporting, but medium sized quality ports that arent all top end... where would the powerband be on a .68 T4 on a ported rotary???
i'd really like some input on this; the 115 housing is driving me crazy.
08-11-05, 09:26 AM
#3
Racing Rotary Since 1983
iTrader: (6)
i am not surprised that you don't get full boost (what is the full boost?) until 5000.
the V1/v2 compressor is 2.18X2.75 w an aggressive top end oriented 63 trim.
add this to a significantly mismatched (too large/heavy for the compressor) hotside wheel and you have a laggy midrange which is a poor autocross fit.
area of the cold side is 4.835 sq inches
area of the hotside is 5.894 sq inches.
hot to cold ratios generally run from 1 to 1 (R85) to 1.2 to 1 favoring a larger compressor.
your ratio is .82!
i am not saying the P hot wheel doesn't work on the 13b, just not w your compressor sizing.
the V1/V2 is a narrow application wheel. i don't know what boost you plan to run autocrossing but the wheel is at it's best between 1 to 1.6 bar. even there is is pretty inefficient, 55% being the rightward edge of the map.
at 1 bar and at max flow it will make 43 lb/min which is 633 cfm and a max 324 rotary rwhp at a low 55% efficiency. probably not a good wheel for midrange tq/hp necessary for autocross.
as to the smaller hotside turbine housing i am sorry but i can't be of direct help as all my experience is w the T3 hotsides. i can tell you that i monitor and log backpressure on my setup and if you have too small a hotside you will easily create 40 to 60 psi of exhaust backpressure. i split both of my turbine housings running too small a turbine housing due to too much heat and pressure.
it is also not good for your motor or turbo of course.
i am sure someone on the forum will be able to advise you but i strongly suggest you find the proper sizing regardless of the cost. i would also switch compressor wheels to a TO4E 46 trim and step down on the hotside wheel til you arrive at a minimum of 1 to 1 area-wise.
i suggest you call kevin draper at Majestic 800 231 5566
good luck,
howard coleman
the V1/v2 compressor is 2.18X2.75 w an aggressive top end oriented 63 trim.
add this to a significantly mismatched (too large/heavy for the compressor) hotside wheel and you have a laggy midrange which is a poor autocross fit.
area of the cold side is 4.835 sq inches
area of the hotside is 5.894 sq inches.
hot to cold ratios generally run from 1 to 1 (R85) to 1.2 to 1 favoring a larger compressor.
your ratio is .82!
i am not saying the P hot wheel doesn't work on the 13b, just not w your compressor sizing.
the V1/V2 is a narrow application wheel. i don't know what boost you plan to run autocrossing but the wheel is at it's best between 1 to 1.6 bar. even there is is pretty inefficient, 55% being the rightward edge of the map.
at 1 bar and at max flow it will make 43 lb/min which is 633 cfm and a max 324 rotary rwhp at a low 55% efficiency. probably not a good wheel for midrange tq/hp necessary for autocross.
as to the smaller hotside turbine housing i am sorry but i can't be of direct help as all my experience is w the T3 hotsides. i can tell you that i monitor and log backpressure on my setup and if you have too small a hotside you will easily create 40 to 60 psi of exhaust backpressure. i split both of my turbine housings running too small a turbine housing due to too much heat and pressure.
it is also not good for your motor or turbo of course.
i am sure someone on the forum will be able to advise you but i strongly suggest you find the proper sizing regardless of the cost. i would also switch compressor wheels to a TO4E 46 trim and step down on the hotside wheel til you arrive at a minimum of 1 to 1 area-wise.
i suggest you call kevin draper at Majestic 800 231 5566
good luck,
howard coleman
08-11-05, 06:21 PM
#4
so howard, you're saying my v1/v2 compressor wheel is only good to 326 whp at 55% efficiency?
my goal with this setup was only 350whp and fast spool (pending the purchase of a new turbine housing) but now you're saying that my ptrim exhaust wheel and my vtrim compressor are a horrible match? i'm kinda confused now...
my goal with this setup was only 350whp and fast spool (pending the purchase of a new turbine housing) but now you're saying that my ptrim exhaust wheel and my vtrim compressor are a horrible match? i'm kinda confused now...
08-11-05, 06:52 PM
#5
Originally Posted by bobybeach
Just thought id bring this post back to life....
Im having my s4 fc turbine housing machined at the moment here in Auckland to accept a garrett to4b p trim turbo with 54mm inducer, this to4b garret with its original 1.15ar housing produced 350rwhp on fc at 12psi, so im looking to see 300rwhp+ on stock manifold at same boost level.
**** it looks and fits in original position, just the cover needed a litle tickle with the die grinder to clear the manifold. But otherwise looks like stock set up just missing the water hoses.
Im having my s4 fc turbine housing machined at the moment here in Auckland to accept a garrett to4b p trim turbo with 54mm inducer, this to4b garret with its original 1.15ar housing produced 350rwhp on fc at 12psi, so im looking to see 300rwhp+ on stock manifold at same boost level.
**** it looks and fits in original position, just the cover needed a litle tickle with the die grinder to clear the manifold. But otherwise looks like stock set up just missing the water hoses.
08-12-05, 08:15 AM
#7
Racing Rotary Since 1983
iTrader: (6)
at standard temperature and pressure there are X number of O2 molecules per volume of air. when combined w the optimum number of fuel molecules flowed thru a rotary engine which has X efficiency a maximum of Y hp is produced.
Y, and no more.
an excellent empirically derived formula that produces very close to real world results is that in an Optimized rotary engine system 1.92 CFM equals 1 rotary rear wheel hp.
compressor maps give us the CFM-lbs/minute... so let's look closer...
"you're saying my v1/v2 compressor wheel is only good to 326 whp at 55% efficiency?"
that's not quite what i said but close...
looking at the V1/V2 compressor map...
at 1 bar boost or 2.0 pressure ratio the Max air the V wheel will flow is 43 lb/min or 622 cfm. divide by 1.92 and you get 324 rotary rwhp. MAX. that's w perfect tuning,ports etc.
as to "efficiency" various wheels react differently w air molecules... when they slip friction and heat are created. heat is the enemy of efficiency as the molecules expand per volume so there are less O2 molecules and therefore less power to be had as heat rises. the V1 wheel w it's aggressive trim is inefficient. the max efficiency island is 73% versus the 46 trim wheel at 76%. in addition to lacking peak efficiency notice as you get to the ragged edge at max flow.... the V1 is at 55% versus 60% for the 46 trim. a good intercooler does
remove lots of the heat but it still starts at a decided disadvantage v other more efficient wheels.
as to peak hp from the V1.... it flows 48 lb/min 694 cfm and will make a max of 361 rotary rwhp. that's at 23 psi.
as to your guy w the FC...
sorting thru the confused nomenclature, he is running a P trim hot wheel. that'd be 5.89 sq inches of average area.
he is running a TO4E (not b) 50 trim compressor which is 2.122X3 or 5.18 sq inches area.
his ratio is .88 which is less, but still mismatched, compared to your contemplated setup.
as to hp from the TO4e 50 trim. at 12 psi the wheel makes Max 40 lb/min or 578 cfm which is 301 rotary rwhp. max hp from the wheel is at 25 psi and is 48 lb/min or 694 making 361.
efficiency ranges from 78 to 65%.
i hope i have been of help. as to turbo efficiency--- sizing matters and it is really easy to both run something that doesn't fit your needs or to do some homework and find a perfect fit.
generally it doesn't cost anymore to run the right stuff.
good luck,
howard coleman
Y, and no more.
an excellent empirically derived formula that produces very close to real world results is that in an Optimized rotary engine system 1.92 CFM equals 1 rotary rear wheel hp.
compressor maps give us the CFM-lbs/minute... so let's look closer...
"you're saying my v1/v2 compressor wheel is only good to 326 whp at 55% efficiency?"
that's not quite what i said but close...
looking at the V1/V2 compressor map...
at 1 bar boost or 2.0 pressure ratio the Max air the V wheel will flow is 43 lb/min or 622 cfm. divide by 1.92 and you get 324 rotary rwhp. MAX. that's w perfect tuning,ports etc.
as to "efficiency" various wheels react differently w air molecules... when they slip friction and heat are created. heat is the enemy of efficiency as the molecules expand per volume so there are less O2 molecules and therefore less power to be had as heat rises. the V1 wheel w it's aggressive trim is inefficient. the max efficiency island is 73% versus the 46 trim wheel at 76%. in addition to lacking peak efficiency notice as you get to the ragged edge at max flow.... the V1 is at 55% versus 60% for the 46 trim. a good intercooler does
remove lots of the heat but it still starts at a decided disadvantage v other more efficient wheels.
as to peak hp from the V1.... it flows 48 lb/min 694 cfm and will make a max of 361 rotary rwhp. that's at 23 psi.
as to your guy w the FC...
sorting thru the confused nomenclature, he is running a P trim hot wheel. that'd be 5.89 sq inches of average area.
he is running a TO4E (not b) 50 trim compressor which is 2.122X3 or 5.18 sq inches area.
his ratio is .88 which is less, but still mismatched, compared to your contemplated setup.
as to hp from the TO4e 50 trim. at 12 psi the wheel makes Max 40 lb/min or 578 cfm which is 301 rotary rwhp. max hp from the wheel is at 25 psi and is 48 lb/min or 694 making 361.
efficiency ranges from 78 to 65%.
i hope i have been of help. as to turbo efficiency--- sizing matters and it is really easy to both run something that doesn't fit your needs or to do some homework and find a perfect fit.
generally it doesn't cost anymore to run the right stuff.
good luck,
howard coleman
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08-18-05, 11:29 AM
#9
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your missing the point of Howards very very good 'lesson', he's NOT going to give you the answer you WANT to hear. However he did give you an answer that will allow you to make an informed and hopefully proper chioce with your upgrade. If you choose not to listen you've only yourself to blame.. I'd be thanking howard up one wall and down the other for his time and very well put together information packet.
08-19-05, 11:02 PM
#10
huh?
im just saying the numbers dont match up. i made this post wondering about a .68 housing and about the t04b vtrim compressor. howard is saying you cant make over 300whp with the t04b vtrim and the 115 housing and there are people making 350whp at 12psi... infact, howard is saying a 50trim wheel in a t04E housing at 12psi is only going to make 301whp.
also, doridori drifter rx7 guy. I in no way was whining about not getting the answer i wanted to hear
"an excellent empirically derived formula that produces very close to real world results is that in an Optimized rotary engine system 1.92 CFM equals 1 rotary rear wheel hp." i'm just wondering where this came from
im just saying the numbers dont match up. i made this post wondering about a .68 housing and about the t04b vtrim compressor. howard is saying you cant make over 300whp with the t04b vtrim and the 115 housing and there are people making 350whp at 12psi... infact, howard is saying a 50trim wheel in a t04E housing at 12psi is only going to make 301whp.
also, doridori drifter rx7 guy. I in no way was whining about not getting the answer i wanted to hear
"an excellent empirically derived formula that produces very close to real world results is that in an Optimized rotary engine system 1.92 CFM equals 1 rotary rear wheel hp." i'm just wondering where this came from
Last edited by jacobcartmill; 08-19-05 at 11:16 PM.
08-22-05, 11:56 PM
#12
Run the .68, balance it with a 60 wheel in the front and .55 compressor housing. Instant boost and great for autocross.
presently i have a 60-1 HI-FI with a .69 P trim, hot side...car made 347@12psi boost was crazy instant right around 5500 rpm i thought that something was going to break.
presently i have a 60-1 HI-FI with a .69 P trim, hot side...car made 347@12psi boost was crazy instant right around 5500 rpm i thought that something was going to break.
08-23-05, 12:53 AM
#13
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60-1hifi same turbo im using. i like it. i feel that it has a broader power band thats more practical for a street car. like the power is there no matter what rpm your in. great for whoopin *** on the street.
08-23-05, 01:15 AM
#14
interesting... i think i might do this.. your 60-1hifi wheel is a bit better and will support a little more power than my vtrim but wow, anywhere near 350whp under 15psi would be awesome.
does your boost drop at all with that smaller housing? i have the same ptrim wheel so your post really is making me want to do it now..
does your boost drop at all with that smaller housing? i have the same ptrim wheel so your post really is making me want to do it now..
Originally Posted by andre sinclair
Run the .68, balance it with a 60 wheel in the front and .55 compressor housing. Instant boost and great for autocross.
presently i have a 60-1 HI-FI with a .69 P trim, hot side...car made 347@12psi boost was crazy instant right around 5500 rpm i thought that something was going to break.
presently i have a 60-1 HI-FI with a .69 P trim, hot side...car made 347@12psi boost was crazy instant right around 5500 rpm i thought that something was going to break.
08-23-05, 09:09 AM
#15
I would make sure that you have a good external wastegate so that you can expell the exhaust quickly. I have the 52mm indygate wastegate by innovative which was pretty costly 650.00 but it does the job well. Trust me the HI-FI and a .69 P-trim is more than enough for street. Also i have raced a porsche and give it a run for the money of the line but mark you I pull off the throttle at 135mph because **** started to get scary. Being paralyzed from a previous accident and laying on my back for a year...i didn`t want to go through that again. But respect was given from the porsche driver.
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