Max effiency turbo build

[Operator]

There is no 'one size fits all' for turbo choice. Smaller turbos spool quicker and typically have better transient response. I like your high compression build, which greatly improves overall efficiency and reduce lag, but GT30s & GT35s have their place. I've driven many NSXs with both and while they won't make the power of your GT40, it may be a better fit for many who like the low rpm instant response of superchargers.

So you are measuring 'crankshaft' power numbers, not power at the 'wheel'? -That's a pretty important distinction.

Well it does not matter how you measure power increase. Starting point is 268 hp and now 711 hp . So it makes 2,65 times more power at 15,22 psi . This side "lake" /europe we use engine power.
Our dyno softwares are build that way ? This TAT system is mayby one of the best. Car manufacturers used same software .

 

[Operator]

Fwiw: My HKS Fcon NSX-specific wiring harness was hand built by Jon Kuroyama of HKS USA himself.

GOOD !

OK ! You got harware , i have software.Who has acces to software ?! This 3.3 ecu is very good system with HKS goodies. When car goes out of dyno room HKS ecu will self adjust fuel maps !
All new ecus has Wide band lambda closed loop control but they normaly just trim base fuel map +/- % . But HKS will trim F.MAP and it sends correction value to fuel trim map what
is now new start point to trim value when load point comes to same point. So it will not start all trimming from zero . It uses last value ..so if your compensations are done right
finaly it will be perfect ! There is 1024 load points to choose is it active or not ! + set up values like volume, sample rate ext .

 

[stuntman]

Well it does not matter how you measure power increase. Starting point is 268 hp and now 711 hp . So it makes 2,65 times more power at 15,22 psi . This side "lake" /europe we use engine power.
Our dyno softwares are build that way ? This TAT system is mayby one of the best. Car manufacturers used same software .

True, but over here everyone measures wheel horsepower. 711PS does not = 711whp; it's probably closer to 600whp which is an important distinction for us in the US.

 

[Operator]

645 WHP . Measured loses 66 WHP . NSX has very low power loses value. One off the best :smile:. Some FWD cars are in same level or lower but those dont have so big tires.

 

[stuntman]

I would agree with that.

So did you end up with a 1.19 twinscroll?

 

[Operator]

I would agree with that.

So did you end up with a 1.19 twinscroll?

Yes 1.19 now .Note ! this turbo is GT4088 not GT4088R . 88R has smaller turbine wheel and housing ( too small !)

Now i have ordered newer desing turbo what shoud be 20-30 hp better at same boost. If is it better or as good as GT4088 i will use it .

 

[stuntman]

Yes 1.19 now .Note ! this turbo is GT4088 not GT4088R . 88R has smaller turbine wheel and housing ( too small !)

Now i have ordered newer desing turbo what shoud be 20-30 hp better at same boost. If is it better or as good as GT4088 i will use it .

It depends on the power level you're trying to achieve. A GTX3582 made similar power levels as you with a much smaller turbine. At lower power levels, the GTX3582 will be a lot more responsive than a GT4088.

iirc:

GT4088R: Compressor Ind/Exd: 63.50/88.00 - Turbine Ind/Exd: 77.00/70.40 (83 trim)
GT4088: Compressor Ind/Exd: 63.50/88.00 - Turbine Ind/Exd: 84.00/77.00 (84 trim)
GTX3582R: Compressor Ind/Exd: 62.50/82.50 - Turbine Ind/Exd: 68.00/62.20 (84 trim)


If you want to go the big power route, I might suggest taking a look at these:

EFR 9180: Compressor Ind/Exd: 67.70/91.00 - Turbine Ind/Exd: 80.00/74.00 (85 trim)
Forced Performance HTA4294R: Compressor Ind/Exd: 67.70/94.00 - Turbine Ind/Exd: 82.00/77.00 (88 trim)

 

[Operator]

Point was max effiency at low boost. GTX35 is good for 2 l cars. And it is not correct choice for this my set up. Low responce is not a broblem if all is done by book as i wrote

 

[stuntman]

Point was max effiency at low boost. GTX35 is good for 2 l cars. And it is not correct choice for this my set up. Low responce is not a broblem if all is done by book�� as i wrote

So making the most power with the least boost possible -at the cost of lower RPM & transient response. Got it.

I hate sounding like a broken-record, but there is no "one-size fits all" when it comes to choosing a turbo.

GTX35s are not just good for 2L cars, that's a pretty erroneous blanket statement because you need to consider the target power level. If someone is targeting 400-500whp, a GT40 is NOT going to be efficient in making that power level, and will be less responsive than a GT30-35 sized turbos. Since my personal goals are 5-600whp when maxing out the turbo (on the borderline of efficiency on the island), a GTX35-sized turbo is a much better choice for better low-mid range power and transient response -where it's the most efficient. Since your goals are different (most power, least boost), that will naturally drive you to larger frame turbos.

 

[RYU]

Great info here. Thanks again guys.

Question:
What would be the best (smallest?) Turbo to use to achieve ~350-400wHP and provide the best and most consistent/linear throttle response?

I assume twin turbos have fallen out of favor? Is so, why?

Will the turbo technology today allow for throttle response at least rival that of a positive displacement supercharger, which isn't great but "good enough" for me.

Appreciate your thoughts.

 

[stuntman]

Post #18 .

The Spoon NSX-R GT I drove made 420ps (~380whp) had an internally gated HKS GT3037 and it had pretty quick response down low like a supercharger.

I'd go with an externally gated GTX 3076R or Forced Performance HTA 3076R and use a DBW throttle with modern anti-lag programmed in to make it respond instantly and feel 95% of a supercharger down low. Modern anti-lag is amazing.

Twin turbos are great but are more complex. For your power level, you would need twin pea-shooters, which most people don't package with TT kits. I'd just go with a simple single.

 

[RYU]

Bookmarked

 

[b00sted]

i agree with stuntman, going with an "oversized" turbo for your hp goals is just buying unnecessary lag and reducing the usable powerband.

 

[stuntman]

i agree with stuntman, going with an "oversized" turbo for your hp goals is just buying unnecessary lag and reducing the usable powerband.

It all depends on the goal and purpose. Operator's goal is to make the most power with the least amount of boost. To accomplish that requires a large turbo. If low end power and transient response is the goal, the key is to look at a Turbo's efficiency map to make the turbo operate as efficiently as possible for the best response for your intended target power. More power will generally cause more lag.

I have to admit that Operator's use of higher than stock compression does help offset some of the lag of using a larger turbo.

 

[b00sted]

[MENTION=16531]stuntman[/MENTION] it is interesting you point that out (compression), despite this being from a B-series let me know what you think, and there is also a direct comparison to a 30 vs 35r

http://www.ej8squad.com/printthread.php?tid=8520

It seems having higher compression didnt change much the spool up.

 

[stuntman]

From their test.

Compression:

Same boost, the higher compression motor made more power with 6-7 degrees less timing and SLIGHTLY more low-end torque which helps spool. While visually it does not look like there's much difference in 'spool' between compression ratios in RPM, that graph does not show the time-based transient response, which is the true 'delay' or 'lag' from a turbo. It would have been interesting if they optimized the tune, fuel, timing, and boost controller for both setups; which may have shown a difference in the RPM that the turbo spools.

GT30 vs GT35:

The GT30 had a torque rise earlier than the GT35 (as expected) and less peak power (as expected). Keep in mind the NSX's 3.0-3.2L is about twice the size of a 1.6L, so the flow and CFMs are going to be quite a bit different. IE, the turbos will choke off at higher RPMs more than on a 1.6L -but they will also spool sooner as well.

 

[b00sted]

The turbo comparison was just to show the difference in powerband when you mentioned the "no one-size fits all", i used to have a boosted itr and went through 3 different turbos until i was pleased with the powerband, clearly a 3 Liter will spool differently either of these turbos, i´m boosting my nsx in january and i went with a 3582R should suit quite well for what i want.

 

[stuntman]

That's a great turbo/size for 5-600whp on the NSX that's responsive for street/road course use. Iv'e driven 4-5 NSXs with that turbo. I ended up with a Forced Performance HTA3586 which is very similar.

 

[b00sted]

any dynos so i can see the powerband?

 

[Operator]

I will get back to this ...but mean while low boost turbocharging video for honda lovers https://www.youtube.com/watch?v=LTzsOVfVRCU

 

[Operator]

Post #18 .

The Spoon NSX-R GT I drove made 420ps (~380whp) had an internally gated HKS GT3037 and it had pretty quick response down low like a supercharger.

You must missed this dyno sheet . "Quick responce down like supercharger" . Supercharger is better between 1500-3350 rpm.
And this Comptech blower engine car has RE 85 in tank ! Mayby there is better dyno numbers like this comptech kit ..but i did not found it.

 

[Operator]

So making the most power with the least boost possible -at the cost of lower RPM & transient response. Got it.

I hate sounding like a broken-record, but there is no "one-size fits all" when it comes to choosing a turbo.

GTX35s are not just good for 2L cars, that's a pretty erroneous blanket statement because you need to consider the target power level. If someone is targeting 400-500whp, a GT40 is NOT going to be efficient in making that power level, and will be less responsive than a GT30-35 sized turbos. Since my personal goals are 5-600whp when maxing out the turbo (on the borderline of efficiency on the island), a GTX35-sized turbo is a much better choice for better low-mid range power and transient response -where it's the most efficient. Since your goals are different (most power, least boost), that will naturally drive you to larger frame turbos.

I think you almost got " it " . I went tru all dyno sheets from this forum what i coud find . Best GT35 kits has 300-500 rpm better responce than this kit on "static " dyno pull . Only few of those.

Most set same responce like Gt4088. "it" is with lowest turbine side back pressure !


Broken reco....Tru , But to get good responce you dont always need to go smaller turbo ..If all is done like i wrote ..you can pic up bigger one to get same responce.
First dyno session with stock 10,2 comp engine i got 403 hp at 3,6 psi boost .Almost same responce . Now three so many updates it makes even better.

GT 35 ...No i am in dangerous zone, but i woud not pick up any garret turbos from "box" ! Compressor/turbine sizes are not in balance. However if you use Gt35 turbine shaft for 2 l turbo engine and
proper 53-57 mm compressor wheel > You got something what has exelent responce and power . Turbine side pressure will stay under boost up to rev limit.
Power lever ..yes it use to be trade/and sale /loose /win but it is getting better and better . 2 l car "normal power" is 400hp easy with any turbo, 500 hp modern engine with correct turbo, responce
is like OEM. 600 hp you will loose 350-500 , but you will get 500-1000 more rpm range at top end.

 

[Operator]

i agree with stuntman, going with an "oversized" turbo for your hp goals is just buying unnecessary lag and reducing the usable powerband.

It does not have to be like that ! And using small turbo you will loose so much at top , building lots of heat , knoc sensitivity ++bad things .
If you want chance C30A natural beheaviour then go 30-35 . Turbo set is complete paggage JUST NOT only turbo.

 

[Operator]

It all depends on the goal and purpose. Operator's goal is to make the most power with the least amount of boost. To accomplish that requires a large turbo. If low end power and transient response is the goal, the key is to look at a Turbo's efficiency map to make the turbo operate as efficiently as possible for the best response for your intended target power. More power will generally cause more lag.

I have to admit that Operator's use of higher than stock compression does help offset some of the lag of using a larger turbo.

OK "there " is two cars front of pit and now you need choose what car you woud like to use in race , track is "common" style circuit .Not a parking lot race.
One with Small turbo system with poor desing and one with big turbo all done by book. Bigger turbo car has 500 rpm lower responce than small turbo car.
But this bigger turbo car has 1500-2000 rpm more power range area at top and 100-200hp more power at same boost.

 

[Operator]

@stuntman it is interesting you point that out (compression), despite this being from a B-series let me know what you think, and there is also a direct comparison to a 30 vs 35r

http://www.ej8squad.com/printthread.php?tid=8520

It seems having higher compression didnt change much the spool up.

"static" dyno pull low or high compressio in same engine does not give you big advantage . But when you are in "war" zone huge differece like stunman has found out.
I did toyota 7M-GTE engine overhaul and we raised compression 9>10,5 (ethanol) and in the dyno it was only litle better . But driver told my it is way better now.