Rb26 Gtr 6 Throttle Or Big Single Throttle? What Is Your Experience

[Drift Motorsport]

What is your experience with individual GTR throttle bodies vs a big single / plenum setup such as hypertune 90mm setup?

Engine is a RB26/30.

The engine is mainly for drift/circuit so response is important. Two turbos will be used for different things. Big T51R turbo for drags and a smaller GT30/GT35 setup for circuit/drift.

Cheers

[The Dan]

You will always get better response from the 6. The standard plenum is capable of handling 1000hp so no need to upgrade for that turbo IMO.

[Drift Motorsport]

Thanks for the input. What are the reasons behind the big single plenum and throttle body setups commonly found on modified GTRs?

[Phobic]

the 6 will definately be more responsive, im sticking with them on my 26/30 and just got the greddy plenum which goes on the 6 itb's

[J'z-R33]

I was discussing this with Rob from RIPZ not that long ago.. this is his responce to my email regarding the topic.

"IMO what most people call response is more "how quick my turbo spools up" rather than the slightly better respose hat is directly related to the 6 throttles themselves.

"On throttle response" is more related to turbo selection, intercooler plumbing, cam timing, mapping etc as when you open the throttle with either arrangement, the intercooler plumbing, plenim and intake tract needs to build up boost just the same (seeing as the BOV has dumped all boost in the system when you previously off throttled).

"Off throttle response" (or how quickly you get engine braking) will be better with the 6 throttles as the engine dosn't have to consume the contents of the plenim before it creates vaccum but in all honesty when you back off at 7000rpm+ the motor is using so much air and it all happens so fast I dought you'd notice a difference there either.

You will notice a difference for the better in a circuit situation where your on and off it constantly and where small throttle position changes through corners will control boost, response and drivability for the better.

Having said that, we always use single TBs with our drift motors where response is the key and with the right turbo the response is great, they are simple and easy to tune so I suppose it is a matter of personal choice rather than being able to quantify the differences on an otherwise identicle engine."

Hope this helps...

[Swiper the Fox]

ive got a nice 6 throttle Hypertune item for sale if you want it (its actually a brand new single throttle item but can be swapped for a multi) save $550 off the new price.

[T04GTR]

whats your experiances with the single vs multi hypertune ones paul?

i know from a tuning stand point single is easier as you can use map as the main load input. where as multi the tps is the preferd main load input.

having said that, with tps you cant change your boost as you like as its the fuel map which is controled by the tps input.. ie. turn it down it will run rich or turn it up it will run leaner....

but if you have a ecu that uses air flow meters it doesnt matter.

i have driven the missus car and its got a greedy plenum with 90mm throttle body and its very doey down low. and doesnt seem to be as crisp on and off the throttle and at small thottle openings.

[Swiper the Fox]

whats your experiances with the single vs multi hypertune ones paul?

i know from a tuning stand point single is easier as you can use map as the main load input. where as multi the tps is the preferd main load input.

having said that, with tps you cant change your boost as you like as its the fuel map which is controled by the tps input.. ie. turn it down it will run rich or turn it up it will run leaner....

but if you have a ecu that uses air flow meters it doesnt matter.

i have driven the missus car and its got a greedy plenum with 90mm throttle body and its very doey down low. and doesnt seem to be as crisp on and off the throttle and at small thottle openings.

simple answer...

drag-dyno-big top end = single TB

street-circuit-response = multi TB

thats why we have single Hypertune on the drag car and the multi Hypertune on the circuit car.

Mark Berry couldnt believe how much difference in response the multi throttle Hypertune made on their Time Attack R32.

Edited February 4, 2009 by DiRTgarage

[T04GTR]

excelent. all i needed to know. what did they have before that?

[The Dan]

whats your experiances with the single vs multi hypertune ones paul?

i know from a tuning stand point single is easier as you can use map as the main load input. where as multi the tps is the preferd main load input.

having said that, with tps you cant change your boost as you like as its the fuel map which is controled by the tps input.. ie. turn it down it will run rich or turn it up it will run leaner....

but if you have a ecu that uses air flow meters it doesnt matter.

i have driven the missus car and its got a greedy plenum with 90mm throttle body and its very doey down low. and doesnt seem to be as crisp on and off the throttle and at small thottle openings.

To overcome that, could you do an overlay map of TPS and Boost? Like 4D mapping etc.?

[Drift Motorsport]

I'll be using a motec so tuning and 4d maps isnt an issue - however the easier it is to tune (ie: map as primary load vs fuel and ignition) the better the result and less dyno costs.

What if I was to run a Map sensor in the factory GTR plenum with the 6 throttle bodies? Obviously this will be less than ideal - but it should be easier/better to tune than using TPS as a primary load.

The problem with a TPS primary load on a turbo car is that the pressure will vary at every RPM and throttle opening. TPS is great for N/A engines because the air flow is roughly proportional to the throttle opening.

TPS vs Boost vs RPM would be required and it would be very messy to tune and sort out.

How do you guys run aftermarket management, with the stock throttle setup, using a MAP Sensor (ie: No AFM)?

[bnr#@]

Power FC D jetro runs 2 map sensors and averages it out. Few other ECU's run 2 for gtr's to...

[GTRNUR]

A multi throttle setup with some hot cams say 270 degrees and hotter causes the engine to pull a pretty poor vacuum at low engine speeds, as was already covered this affects tunability at low engine speeds as your map sensor is bouncing all over the place. Running a TPS -> Map changeover solves this, as does using MAF sensors... But.

Vacuum is also used for your power assisted clutch and brakes. Ever tried driving a car in traffic that uses multi throttle and has a set of 280 degree cams? There is not a great deal of power assist going on there any more. Its ok if your track racing it because on a gear shift it will pull a vacuum to allow the boosters to work, but not in traffic when your RPM isnt getting high enough to allow engine vacuum to really build. Be prepared to have to use the hand brake and the brake pedal to stop. Single throttle doesnt solve this, but it does make it a lot better, at the cost of a tiny bit of response.

In case your wondering why multi-throttle is more responsive, its because there is a few litres of filtered air at atmospheric pressure ready to go the moment the throttles are cracked open. With a single throttle setup with the throttle is closed you not only have the engines cylinders that are in vacuum state, but the entire plenum that is usually 4-5lt in capacity that is also in a vacuum. When the throttle is cracked open it takes a moment for air speed to equalise that vacuum back to one atmosphere or above. The delay is due to the volume of the intake piping, and intercooler restriction/volume.

One other thing. TPS->Map change over is a complete pain in the ass to tune if you have a responsive turbo setup because if your making boost in the low RPM range (<below 3400 rpm or so), its in the range that you want to achieve some economy and drivability. All of the sudden your on boost and need map correction. So my opinion is multi-throttle, small turbo setups and cams < 270 intake duration. Single throttle, drag/circuit race turbo setup, large cams.

Edited February 4, 2009 by Vspec R33

[NXTIME]

yep, big cams = little vacuum to assist brakes at low revs. However, a vacuum reservoir or alternator/vacuum pump off a 4WD Nissan should solve this problem.

[Drift Motorsport]

I definatey want to run the MAP sensor as the primary load vs inj/ign on the motec. How are the D-Jetro MAP sensors setup and where are they located? If two map sensors are required, would one be running on the plenum and the other running after the turbo and then you would take an average value?

A single throttle will solve this tuning issue, but im sure that there is a viable option to keep the multi throttle whilst running map sensors. The cams I would be running at the moment are around 264 duration or there about apexi units.

[GTRNUR]

Those cams and multi-throttle is a soft setup, it will be fine. You wont have vacuum issues and the car will be quite drivable and tunable on a map system. Map sensors require a vacuum source. They both connect to the plenum, engine side of the throttle bodies.

[sky30]

anyone done back to back dyno results on multi- throttle vs single throttle??

[hattori hanzo]

On 2/5/2009 at 1:15 PM, sky30 said:

anyone done back to back dyno results on multi- throttle vs single throttle??

Bump, anyone? 

[Lithium]

10 hours ago, hattori hanzo said:

Bump, anyone? 

I'll point out (unless I am missing something) what should be relatively obvious on this, with equivalent for equivalent ITB vs single throttle plenums (same runner length, same plenum size and design) the power delivery should be pretty much identical as once the throttle is wide open everything should be much of a muchness.  Any differences are likely to be in the behaviour at throttle transitions.

Edited April 29, 2018 by Lithium