Hi,

I'm planning to do an engine conversion project of Mazda 808 sedan with 13BT REW engine. Parts which I had bought for my set up are as follow:

Engine;
Ikeya Sequential Shifter
Lead Coil for stock ignition
Magnacores Wires for stock ignition
Greddy Elbow w/ flange
Greddy Type RS BOV
Denso Fuel Pump
Lightweight Main Pulley
Water Pump/ Alt Pulley Kit
Power Steering Pulley
Rebuilt Starter
Greddy Boost Controller
PS/AC Belt
Street Ported Rotor Housings ( Ceramic Coated )
Water Jacket Mods
Install Rotor Bearings FD OH Rebuilt Kit ( 1011# )
HKS Twin Ignition
Used Apexi Power FC Gen 3 with New commander Gen 4 FC Datalogit
PWR Intercooler
PWR Radiator
PWR Oil Cooler PWR Fan 385mm
4 X 850cc Sard Fuel Injectors ( RHD Japan )
Sard Fuel Regulator + Adaptor Oil Catch Tank
Rice Racing Water Injection Kit
RF300 exhaust ( Exhaust Technology )
Mid Resonator ( Exhaust Technology )
Complete OEM Apexi Seals NGK Platinum plugs (All # 9's)
Magnacore wires ACT MZ11 PP
Competition heavy duty sprung full face disc FD
ACT Ultralight flywheel With CW and hardware FD Optional release bearing
FD 13B Electronic Oil Metering Pump Adaptor

I'm planning to use the car for street application and my target power is 350rwhp max. I was recommended the following turbos:

Turbonetics GTK500
Turbonetics S500
Garret GT35
Garret GTX35
Airwerks Borgwarner S300

Can anyone out there please advice which turbos above most suitable for my set up and which size of wastegate should be used ? Your advice is highly appreciated. It's my very first time into rotary and never done turbo set up before. Thanks a lot.

David L

 

Is it a 13bt or a 13brew? Either way, look into bnr hybrid turbos. It should meet your power goal while being a bolt on.

 

Welcome to rotaryland David,

thanks for the list as it helps us help you.

the key from your post is your 350 power objective. the OE twin turbo setup will make 350 but the manifolding is an unfortunate design that retains heat. going single will not only make more power but will help your engine by removing heat.

heat is a key as the rotary makes approx 400 degrees F more than piston motor. it also takes approx 30% more airflow to make the same power as a piston motor.

the good news is the engine flows lots of air so w a turbo it isn't a problem.

this does mean when you are looking at turbos you take the power output and divide it by 1.3 to get ROTARY power.

all this adds up to a big disqualification to the first two turbos on your list. simply stated, you need larger turbine wheels and larger hot side housing A/Rs than they offer.

both turbos are a T3 (small) hotside and come std w a Stage 3 T3 wheel.

given your 350 objective, you are looking for a turbo that flows 47 pounds of air (or more) per minute.

the Turbonetics GT-K500 does have the proper compressor size for you, 6.38 square inches average area but it has a small hot (exhaust) side at 4.51. also, the .63 A/R housing is way too small.

two better options would be the normal Garrett GT3582r... the same 6.38 compressor but w a 5.17 sq inch hot side turbine wheel or the Borg Warner S300 part number 177272 or 177280 (same but w a 90 degree turn in the output nozzle). the BW has approx the same compressor but has a 6.31 square inch hotside wheel. either turbo would work well and be capable of making a bit more than 400 down the road.

one area on your list that needs to be upgraded is fuel. you don't have enough injector capacity.

four 850 CC/Min injectors. 3400 CC/Min.

that is wide open. you don't want to run them at more than 85%

3400 X .85 = 2880

injectors, once opening and closing, have slippage or lag. figure `13%

2880 X .87 = 2514 CC/Min max net delivery.

350 HP is 47 pounds per minute of air. at 10 AFR, that is 4.7 pounds of fuel which is .74 gallons per minute which is 2801 CC/Min

that is at 350 hp... the turbo will make and easy 50-75 more hp and you will be out of fuel and warping your apex seals.

you need to replace your secondary injectors w 1600s or 2000s.

you also need a 0-100 psi pressure transducer/sensor. screw it into your fuel pressure regulator and datalog fuel pressure.

good luck,

howard

 

Hi Howard,

Thanks for the detailed explanation, even though I could not 100% comprehend them as I'm new to automotive. Initially, I wanted to go for stock twin turbo set up, but I was told by many aussies that this stock twin set up will not fir into my engine bay. So they asked me to forget this set up.

You were saying the following: " this does mean when you are looking at turbos you take the power output and divide it by 1.3 to get ROTARY power." Are you saying that for example I select a turbo which can hold 500HP, does it mean 500 / 1.3 = 384HP. Does it mean if this turbo is installed on my engine, I'd get power around 384HP coming out from my engine, is this right ? Kindly advice.

You were saying this: " two better options would be the normal Garrett GT3582r... the same 6.38 compressor but w a 5.17 sq inch hot side turbine wheel or the Borg Warner S300 part number 177272 or 177280 (same but w a 90 degree turn in the output nozzle). the BW has approx the same compressor but has a 6.31 square inch hotside wheel. either turbo would work well and be capable of making a bit more than 400 down the road." Out of above turbos, which turbo you would recommend best ? Is it true if there's a 90 degree turn in the output nozzle, it would reduce the power of the turbo as there's turbulance ? I would like to leave the decision to you. Please advice.


Regarding fuel injectors, I had decided to use 4 X 850cc set up as I had already bought new sets of fuel injectors, it's difficult for me to sell them as I mentioned earlier, rotary engine is really rare here. So what would you suggest if I stick to this fuel set up ? Could I still attain 300HP minimum ?

So please suggest what turbo I should use and how much is the price of it and the 0-100 psi pressure transducer/sensor too including freight to Bandung 40262, West Java, Indonesia via postal service by air ? awaiting for your reply. Thanks.

David L

 

Hi,

Thanks for the reply. I'd searched BNR and they offerred the upgraded stock twinturbo. Unfortunately, i was told by many aussies who ever done such set up, it'd not fit in my engine bay.

 

Hi,

I forget to ask anout 3mm apex seals. I was told by several rotary tuners that stock apex seals could withstand up to 300HP considering that I'm only using the car for daily driven, so I'd not constantly using such power. What would you have to say about that ? Do you think I still need to upgrade my apex seals ? Please advice, thanks.

 

David,

given that you are "new to automotive" and in addition you are setting out on a rotary/automotive i would say you are in deep waters. this is not a negative or criticism rather a caution for you...

advice is available from so many sources and not all of it may be appropriate.

you will need to be able to sift through it and find both the proper answers and the answers that fit your project.

a specific piece of hardware might be good for me but not you.

given your list of initial acquisitions i probably misjudged your needs. some of the items fit into a much higher hp situation... many of the items are good pieces and will fit your build well.

i think you might be better served w a smaller turbo than the GT35 or S300 62. both of these will make considerably more power than 400.

the problem w a larger turbo and your injectors is there will be times when you will boost over the 350 number and will be out of fuel and then it is rebuild engine time.
you really need a turbo that will make 50 pounds per minute TOPS.

given your objectives it is too bad you can't carve up the inner fender well and run the OE setup as it would fit your power objectives. the OE setup works well at the 350 level. do take second look at what it would take to mod your chassis for a fit.

one major negative w the OE setup is that your excellent Rice Racing AI system would be difficult to properly fixture.

if you do go single i suggest you take a close look at the HKS cast iron single manifold. it is compact and a nice design for your hp level. it is just a question of fit.

i suggest you look at a TO4e 50 or 60 trim compressor which is similar to the Turbonetics. while they are an older design, they are still excellent within their output level. in addition, the TO4E is a "commodity" item... in other words they are very inexpensive if you choose not to pay for the "branding."

as to the confusion re "horsepower" piston and rotary.

typically when you shop for a turbo you will see it is rated... let's say you see 500 hp for a specific turbo in the advertisement.

that is piston hp.

you simply divide it by 1.3.

so a 500 hp advertised turbo would make 385 rotary.

500/ 1.3 = 385

as to your engine....

is it apart? you mention streetported housings, ceramic coated rotor housings, and coolant mods...

tell us more about your motor.

as to apex seals... given your power objectives any good condition seals will work assuming a proper tune etc.

stock apex seals are 2 mm. 3 mm seals are 50% thicker and HEAVIER. they generally do not seal as well and are harder on the housings. the primary reason for their existence in 2013 is to allow the apex seal groove to be re-machined to regain proper apex seal to groove clearance (.0015-.002).

there, now, is a better way to re-gain proper clearance. Goopy now offers a 2 mm seal that is .004 oversized which allows, after a bit of fitting/filing, the recovery of proper clearance.

if your engine is in good shape and together you do not need to be concerned about apex seals 2 mm or 3 mm etc.

Rice's water injection setup your motor will greatly benefit as far as longevity.

your 4 850 injectors will work for you as long as you make no more than 350.

i do not sell turbos. perhaps others on the board might be of help here. i can refer you to a source for a proper sized TO4E if necessary.

i recommend you run 10 heat range plugs in all four positions to decrease rotor housing growth around the plug holes. you should have no problem firing them w your HKS Twin Power and good wires.

finally, i recommend you do some searching on this board. literally all the answers to your questions are here somewhere. i do recommend you continue to ask questions. after your turbo situation gets resolved you might want to start a build thread in another section.

howard

 

850ccx4 = Not enough fuel for your goal.

Turbo: You always want a turbo with a bit more capabilities than your power goals. Working the turbo hard will create hot exhaust and intake temps.(no good)

For example. Im aiming at your power goals with a max of 15 psi.

 

What about the BW S200? http://www.full-race.com/store/borgw...670-turbo.html
58lbs/min should spool up really quick and hit your target of 350HP easily without going crazy on boost levels. Also RR WI will increase the efficiency of the turbo by 4% iirc from emailing him. Doesn't sound like much but it is considering the other advantages it gives.

 

i like Grant M's suggestion.

the BW S00SX7670.
BW part number 177268
add the twin scroll T4 1.00 A/R hotside P/N 177193

compressor area 5.419 V 6.38 for the GT35 so a better fit for your power objective.

the turbo can make 425 hp and you have fuel for 350.

you need to lose your 850 secondary injectors and replace them w 1600 or 2000. cost is around $270 for two.

cost not to do it:

your engine.

howard

 

All right I'll purchase this BW S200SX 7670 turbo with T4 Twinscroll 1.0 A/R. What about the downpipe flange ? Should I use the 3" V Band type ? Please confirm. So does the HKS cast iron exhaust manifold fit into this turbocharger ? If yes, would you happen to know whether this set up would fit into my 808 sedan engine bay ? Thanks