Garrett G Series

[hardsteppa]

Have to say again, the midrange torque is frkn amazing. Just don't want to blow the thing.

[Dose Pipe Sutututu]

11 minutes ago, hardsteppa said:

thank you gentlemans's as always for your inputs. What do you think about overspeeding the turbo at 1.5 bar boost, 7500rpm? Assuming a VE of 95% which may drop off at upper rpms, shouldn't see more than max 55lbs per min?

Really only safest way is to get an emap installed or turbine speed sensor or both and send it.

I feel you'll be very knock limited as you move away from efficiency island and your emap shoots up.

I recall it's on 98RON?

What's your ideal power goals and when you want to see peak torque? 

[hardsteppa]

was looking at turbo speed sensor but you know i'm on a good old povspec Apexi PFC....so would would need to be an exxy standalone gauge unless i can successfully calibrate it thru Datalogit.

Yep p98, good memory there; knock levels on the PFC are actually consistently way lower than the ATR43 and GTX3076. I'm happy enough keeping the same 300~rwkw and having so much more midrange; dyno will tell but still seems to pull just as hard to 7000rpm. As soon as I'm firmly decided on keeping this or moving to a 770, will head back to PITS for a non-sexual touchup on the dyno.

[GTSBoy]

It shouldn't be too difficult to find an arduino based display for these speed sensors. 150krpm sounds like a lot to us, but it's nothing to a microprocessor these days.

[Lithium]

12 hours ago, hardsteppa said:

was looking at turbo speed sensor but you know i'm on a good old povspec Apexi PFC....so would would need to be an exxy standalone gauge unless i can successfully calibrate it thru Datalogit.

Yep p98, good memory there; knock levels on the PFC are actually consistently way lower than the ATR43 and GTX3076. I'm happy enough keeping the same 300~rwkw and having so much more midrange; dyno will tell but still seems to pull just as hard to 7000rpm. As soon as I'm firmly decided on keeping this or moving to a 770, will head back to PITS for a non-sexual touchup on the dyno.

GENERALLY speaking, if you are just looking for more midrange with the same peak power then you're unlikely to actually end up pushing the turbo any harder.  

Mechanical efficiency (how much power you make vs air/fuel consumption) drops as rpm increases, so it's theoretically possible to make more power at earlier rpm with the same air flow.    Basically the turbo will be working *less* to make a bit more torque in the middle than it would be to make your peak power at the top end.

G30 660 keeps close to it's peak flow capacity to boost levels well beyond what you'll run on an RB25 on P98, so if you aren't aiming for a higher peak number then I feel fairly confident that your turbo won't be the limitation for filling out the torque curve past boost threshold - it will be how hard you are willing to lean on the engine with that fuel.   I don't see any benefit going to the G30 770, its the same hotside.   It sounds like you've fallen on a pretty good "goldilocks zone" of what works for you... I wouldn't change unless you had a strong reason to.

Edited November 24, 2022 by Lithium

[discopotato03]

I agree , law of diminishing returns .

Thanks for your G30-660 results , it'd be the one I'd use from the G series range .

[Dose Pipe Sutututu]

16 hours ago, GTSBoy said:

It shouldn't be too difficult to find an arduino based display for these speed sensors. 150krpm sounds like a lot to us, but it's nothing to a microprocessor these days.

or go ghetto and hook an a electronic boost gauge to a damper & coil on the turbo housing or exhaust manifold flange.

You'll understand what the turbo is doing pretty quickly with that data

 

[Lithium]

On the topic of EMAP, while it's kinda anecdotal evidence to a degree - the boost curve if you're purely gate controlled, or the wastegate duty curve to maintain a fixed boost level using electronic boost control can totally paint a bit of a picture of what EMAP is doing.   If your WGDC is pretty flat to achieve flat boost then it's typically fairly good sign EMAP is pretty kosher, if you start needing more WGDC (like 25% at 4500 then 30+ at 6500) then it's a safe bet that you're walking to the dark side of 1:1 EMAP/boost

[Komdotkom]

On 23/11/2022 at 8:26 PM, hardsteppa said:

Have been using a G30-660 with a .73 exhaust housing the last few weeks. On RB25det at 1.5 bar, it is quite possibly the best turbo I've had on the car, sooooo responsive and pulls HARD to 7000rpm. It also controls boost better as on my setup I would get boost creep on ATR43ss2 and GTX3076gen2 that wanted to keep going past 1.5bar in the higher rpms. No dyno result as yet for it though.

Flame suit on, I know there's likely to be alot of "that's too small!" and from the compressor map, it might be close to the turbo's limits but a while back I was driving a stock BMW turbo 118i that was killing my car for daily driving and zippiness. This turbo seems a great match for daily driving and tighter circuits, mountain roads etc. Still wondering if I should move up to the G30-770 though... Thoughts are welcome.

I've just ordered a G30-770 for mine, I'll let you know.

[elsk]

On 11/25/2022 at 1:56 PM, Lithium said:

If your WGDC is pretty flat to achieve flat boost then it's typically fairly good sign EMAP is pretty kosher, if you start needing more WGDC (like 25% at 4500 then 30+ at 6500) then it's a safe bet that you're walking to the dark side of 1:1 EMAP/boost

I did have to make my WGDC similar to your example, sorry for my lack of knowledge but what is 1:1 EMAP/boost?

Edited December 9, 2022 by elsk

[GTSBoy]

EMAP is exhaust manifold pressure. Boost is inlet manifold pressure. For making really good power, you would prefer EMAP to be lower than the boost pressure. When EMAP exceeds boost pressure, it adds more flow restriction to the engine, driving more reversion of hot exhaust gases back into the cylinder, which just generally makes absolutely everything about trying to make power worse.

1:1 is an expression of the ratio of EMAP to boost pressure.

[Lithium]

35 minutes ago, elsk said:

I did have to make my WGDC similar to your example, sorry for my lack of knowledge but what is 1:1 EMAP/boost?

All good, I used to overexplain everything - now I'll just assume people know or will ask if they are interested

EMAP is the exhaust manifold pressure, basically.    When trying to make an engine efficient one of the best things to do is make a good pressure ratio across it, or in other words - make the exhaust pressure as low as possible compared to the intake (/ boost) pressure.   The reason for this is that fluids (in this context, gas...) want to even out pressure.   If you have higher exhaust manifold pressure than intake manifold pressure it actually starts becoming harder work for the engine to keep drawing air in and pushing exhaust out.   "1:1" is basically what naturally aspirated cars run at, and for all intents and purposes the engine is "not restricted" due the turbo and instead is operating more like it just has super dense air with minimal cost.

When you start going to the bad side of that 1:1 ratio the exhaust from the last combustion cycle starts getting significantly less reluctant to get pushed out of the engine and instead kind of hangs out and reduces the amount of left over space in the cylinder for the next bunch of new fresh air.   This directly affects volumetric efficiency, exacerbated by the fact that the left over exhaust gas is also hot and going to generally make things less nice and less efficient in the cylinder.

The reason that your wastegate duty cycle needs to start going up is that it's not JUST boost that affects the wastegate, exhaust manifold back pressure also works against the wastegate valve - so when it starts getting higher than the boost pressure you start seeing that you have to increase wastegate duty to offset the effect of that as well.   Basically, OVERLY simplified (it's not quite this simple) if exhaust back pressure never exceeds boost pressure then you'll typically see a fairly flat wgdc to get a flat boost curve.    So if you're needing 25% duty to hold 20psi of boost from 4000rpm to 8000rpm then the turbo is probably operating in a fairly happy place.

If you are running 25% duty from 4000-5500 to hold 20psi for boost, but then from 5500 to 8000rpm it creeps up to 35% while you aren't actually seeing any more boost then there is "something" making it need to do that, and often it will be the increasing exhaust back pressure trying to force the wastegate open from the exhaust side.  If it's pushing the gate open that effectively, it's ALSO going to be working against the engine during it's exhaust cycle - so effectively the mechanical efficiency of the engine starts taking a bit of a hit, as with volumetric efficiency due to more exhaust gas hanging around in the cylinders.

Hope that kinda makes sense.

 

Edited December 9, 2022 by Lithium

[bcozican]

Not a G series so dont know if its wanted in here?

If not can post in dyno results,  but thought it might be of interest to show the actual capacity to move air of the Gen ll GTX3582 when pushed a bit and right everything behind it

Not front loaded for mass response and specific for circuit car with sequential

Rb2.7 neo head vct high compression

845 rwhp at 33psi 8500rpm hub dyno

Dont get too technical on me I just drive and its fast it was more for interest sake of those whom might care 😄

G35 1050 1.01 to come soon

 

Edited December 14, 2022 by bcozican

[Butters]

Not sure what you would gain by swapping to the g35-1050, your result is very good and kind of better than my g35-1050 (.82) on a rb26. 

 

Stick with it I say. 

[bcozican]

Very different engines and also different goals though

But yes it did surprise

Edited December 14, 2022 by bcozican

[Full-Race Geoff]

gtx3582R gen2 is a great turbo from the previous generation.  i can understand why youd love it on that 2.7L 

but the g35-1050 is very different.  you might be happier with the g35-900 or the g40 if youre targetting bigger power

[Lithium]

19 hours ago, bcozican said:

Not a G series so dont know if its wanted in here?

If not can post in dyno results,  but thought it might be of interest to show the actual capacity to move air of the Gen ll GTX3582 when pushed a bit and right everything behind it

Not front loaded for mass response and specific for circuit car with sequential

Rb2.7 neo head vct high compression

845 rwhp at 33psi 8500rpm hub dyno

Dont get too technical on me I just drive and its fast it was more for interest sake of those whom might care 😄

G35 1050 1.01 to come soon

 

That's a fantastic result mate, nice work and cheers for sharing.   The Gen2 3582 has often been well underestimated in terms of it's ability (and effective size), but that's probably gonna be on kill haha.   

What are you hoping to see with the G35 vs this?

[bcozican]

50 minutes ago, Lithium said:

That's a fantastic result mate, nice work and cheers for sharing.   The Gen2 3582 has often been well underestimated in terms of it's ability (and effective size), but that's probably gonna be on kill haha.   

What are you hoping to see with the G35 vs this?

From here I dont know to be honest I didnt expect to have the engine I have and that result from my old turbo

I bought the G35 1050 9 + months ago to go in a cast 9:1 rb28 with rb25 head converted to solid I was going to build to get a nice 800hp ish

due to many factors Ive just put in a Billet Nitto 2.7 with full racehead at 11:1 and got that results because I had to make an event and didnt have time to put the new turbo setup on (needed fab)

So spose id expect a little bit more, a newer turbo (time use wise)  and be able to live in a higher rpm range a bit better which is where this needs to be run ?

[Davets]

Here's another SR result from FB... seems pretty high for P11 cams and 25psi. 

link

S15 SR20 VVL Head
Using a Stock Head woth upgraded valve Springs  std p11 Cams
Garrett G25  660 Turbo .63 Housing
Plazmaman intake manifold &INTERCOOLER 
Haltech Elite ecu on Board 
Making 565Hp@Hubs on 25psi

[hardsteppa]

On 25/11/2022 at 1:24 PM, discopotato03 said:

I agree , law of diminishing returns .

Thanks for your G30-660 results , it'd be the one I'd use from the G series range .

I might add..this is a Pulsar turbo, I can't keep buying top of the range turbos just to experiment. However since it's been soo awesome lol (the thing is just constant T51R spool sound too I might mention) and the turbo I'm going to settle on using, for the next few years at least, have bought a Garrett G30-660 supercore so will be interesting to see if there's any noticeable driveabilityness difference...ness between genyou-wine and knockoff.

Anyone want to buy an almost-new Garret GTX3076Rg2 or reasonably-used Hypergear Garret-core ball-bearing ATR43ss2 ?