Full-Race Geoff

twin efr6258 would still be my favorite turbo setup. if it had to be single turbo then thats a different conversation, but 2 good twins work and can be magic on these engines

keep in mind the 9274 has a considerably smaller compressor inducer trim, so it plots out really well!

ive done a back to back with my friend Evans Tuning, where the only change was pistons (CR). if youve got data otherwise im always happy to learn

increasing compression typically corresponds to an increase in HP / lb boost. it does not change spool in my experience. That said the exhaust flow requirement is likely to go up in some capacity, particularly with the p&p so increasing turbine swallowing capacity to 1.45 a/r would make sense as a consideration provided youre aware of turbo shaft speed.

The 9180 1.05 can easily supply 500rwkw worth of airflow. the rest of the setup will need to support this, fuel is the biggest factor (knock) Full-Race has a few in stock, there will be a sale for the big holiday in the states this weekend

7064 is still a good turbo! the YB cosworth guys are over the moon for this... older tech 2L engines like sr20 and 3s seem to love the 7064 due to lower emap up top and easy to run external WG on twinscroll (compared to 7163)

it depends entirely on the application - altitude, engine size, max rpm, boost level, VE, etc. typically the 9174 exhibits increased emap at most points

we built the turbo kit on steph's drift car. its a 2.6L engine from a toyota sienna minivan, typically he revs to 7800-8000rpm depending on the track and gearing. Turbo setup is divided t4 manifold, very similar to evo but flipped so its a top mount obviously. the turbo started as 8374 0.92 a/r, then tested 1.05 a/r 8374 and went back to 0.92 once they had the nitrous on the car. He is battling V8s and 2jz's so he needs as much bottom end torque as is possible. once they switched to the 9174 he kept the 0.92 a/r for a while due to the setup already being built and in place. as of right now i believe he is back on the 1.05 a/r. keep in mind there is a lot of nitrous on this engine

that is correct, 9174 works best with the big 1.45 a/r housing when pushing the turbos limit. The 74mm turbine is relatively small to swing the 91mm compressor so anything that can be done to reduce preturbine drive pressure at high rpm / high boost is a win for this one.

Thats my man clinton! 9174 1.45 a/r external wastegate evoX.. he has embarassed some serious vehicles with this evoX

agree 100%. thank you for posting up Peter! when i was younger and had less experience, i also thought the 1.00 target was a good idea. now i understand peak turbine efficiency is typically found around the 1.00 a/r range. the larger a/r will flow more with a loss in turbine efficiency (counter intuitive i realize). the tradeoff is transient response, at least for a radial flow turbine

I am interested to see your impressions with the bigger housing. It does lose a bit of response, I personally prefer the 1.05 for most RB engines due to the balance of response and turbine efficiency. To your second point, however, the twin EFR is another level of breathing compared to the single EFR. when youre at the point of this volume of airflow, I believe the big twins really are the call

if anyone needs turbos or speed sensors, we have both in stock and happy to match any prices online. also we have a new Turbo Speed Gauge that is pre-programmed for EFR turbos:

that is a lot of motor for that little turbo. but to me this looks like a massive exhaust leak and/or boost leak. purely guessing without the turbo speed sensor data

It's possible from that chart a combination from too light WG spring + too much preload+ lots of backpressure. Purely guessing from the other side of the planet and not aware of your setup ? Edit I see the 6boost above which turbo and housing is this

Not that I am aware of.

^^correct - swap turbos, retune. No other changes to the hardware, it is 100% plug and play for each other. we have the turbos in stock with t2 IWG if you want to pull the trigger. the powerband is pretty terrifying if thats what you are looking for

if you want responsive 1000+hp on any twin turbo application my opinion is EFR7163 can not be beat. This is literally off-the-shelf indycar turbo setup. Spool difference between 6758 and 7163 is about 300-400rpm depending on gear, but for this power level its an easy decision

@Lithium The max turbo speed rating is determined based on tip speed of 560 m/s maximum. The smaller diameter wheel must spin at a higher RPM to cover 560 meters per second compared to a larger diameter wheel. Tip speeds above this 560m/s level are where any turbo is likely to fail

im interested to see the chart, and whatever info you can share of the tune/setup. how much boost, ignition advance and WGDC? Do you have turbo speed sensors? Do you have a boost chart showing RPM vs boost and where are you reaching 1bar boost? obviously there are many changes that can be made to extract more power, but thoroughly understanding the baseline is important before changing anything else All wastegates internal or external will have a small leak from the lower port. In the case of turbosmart IWG actuators, if you use a 4 port solenoid with pressure in the lower canister it can push assembly lube out of the lower bushing. Turbosmart is fantastic to deal with, if you have any concerns send them a photo of the actuator. yes 8374 1.45 was a popular evoX turbo, but 9174 1.45 has pretty well displaced it 8474 and 9280 both required a new compressor housing design. This will not be released until 2018

the 9174's have been very popular lately, for 2 reasons: -borgwarner has the most bizarre production methodology ever, and they are spititng out 9174s only (not 8374, not 9180) -the 9174 has an internal pricing error causing it to be the least expensive of B2 frame EFRs. we get shipments of 9174 with iron and alloy bearing housing. The main factor for consideration if you will use alloy is that watercooling is mandatory. the iron turbos are not nearly as picky. however the alloy turbos are crazy lightweight, its a 7lb difference

ok good - 6758 is not nearly as sensitive to the surge margin as 7163. just something simple to keep in mind since its just a 90 degree bend and a filter on the end

Ok - I prefer to see 3" as the smallest diameter for the inlet. edit: the 2.5" will work fine, but 3" can better avoid any surge with 7163s

looks good! only question is regarding the intake tubes/filters - are they 3" ? or 2.5"

-do a boost leak test -check for exhaust leaks (very likely) -get turbo speed reading properly -get preturbine backpressure reading report back