Thoughts on this .. G35-1050 pulsar result

[Butters]

After being a little disappointed with my initial g35-1050 genuine turbo result. To be fair the head started to lift so not all things as they should be.   

I was struggling to crack 600rwhp at 24 psi on an rb26 E85. My other rb26 with old school gt3582 does 600 rear with ease.  

I was hoping for some bigger numbers so ... 

 

I have been watching this closely and it seems very similar to what I experienced, this is however a "Pulsar" version. 

What do you think is going on ?  Surely 27psi on 2.5L cammed engine should be over 600 ?

Or is the pulsar not really a g35-1050 ?

 

 

[Lithium]

Something is definitely not right there.  I know a good number of people who have used Pulsar G35s and others from their range, as well as the genuine Garretts and they seem more or less on par with each other when everything is working right.  

Do make sure your turbo speed sensor port is sealed etc.  I've definitely come across people with big leaks out that port costing spool and power.

Fwiw I've definitely seem numbers well north of those from both Garrett and Pulsar versions and to shake the inevitable Dyno debate, this is probably relevant (and gives you something/someone to look at).

Andrew Hawkins also went north of 800hp with his 

 

Edited June 24, 2022 by Lithium

[GTSBoy]

It seems to me, from a casual inspection of the compressor map, that at ~80 lb/min and 1.65 PR, you are right up against, if not to the right of the choke line.

[robbo_rb180]

Something not right aa friend built and tuned a stagea with a stock rb25 (Hg and studs, dbw, e85) genuine g30 1050 at like 20psi did 550hp.

I'd be checking there isn't any restrictions or leaks in intercooler or piping. Has the tuner been conservative with the timing?

[Butters]

On 6/24/2022 at 3:57 PM, Lithium said:

Do make sure your turbo speed sensor port is sealed etc.  I've definitely come across people with big leaks out that port costing spool and power.

Yer i will be doing a full leak test prior to dyno this time.

 

On 6/24/2022 at 4:00 PM, GTSBoy said:

It seems to me, from a casual inspection of the compressor map, that at ~80 lb/min and 1.65 PR, you are right up against, if not to the right of the choke line.

Not sure what you are saying ?  800hp in reality ?

[GTSBoy]

On 6/24/2022 at 5:40 PM, Butters said:

Not sure what you are saying ?  800hp in reality ?

600 rwhp is typically about 800 at the engine, is typically about 80 lb/min of airflow is right up against the RH edge of the turbo map that that relatively low boost number you report.

[Lithium]

On 25/06/2022 at 1:50 AM, GTSBoy said:

600 rwhp is typically about 800 at the engine, is typically about 80 lb/min of airflow is right up against the RH edge of the turbo map that that relatively low boost number you report.

That is super aggressive drivetrain loss estimation, paired with a harsh BSAC estimation considering this will be aboit E85 setups. 

There are people in Oz making 600whp with turbos which flow 10lb/min less than that.  Hub dynos and roller dynos from some other countries will do around 10whp per lbmin of airflow

[Butters]

The g2 gt3582  is around 57lb/min on the same part of the compressor map and seen many rb25/26 turn 570-600rwhp  on this boost level (24psi 1.65PR).   Also run 135-140mph in rwd chassis.   Fat boy gtr's 128mph haha. 

I could be reading this wrong though ?

 

What i would have expected is the 24 psi  80lb/min to translate into at least 650rwhp and maybe near 700rear

Considering 34 psi makes 850rear on hawkins gtr,   Making 25 rwhp(600@24 to 850@34) from each 1psi seems like a LOT !

 

[GTSBoy]

On 6/24/2022 at 10:03 PM, Lithium said:

That is super aggressive drivetrain loss estimation, paired with a harsh BSAC estimation considering this will be aboit E85 setups. 

There are people in Oz making 600whp with turbos which flow 10lb/min less than that.  Hub dynos and roller dynos from some other countries will do around 10whp per lbmin of airflow

The 25% loss on roller dynos is not drivetrain. It's tyre-roller interface. That argument is long dead. If we do not want to have to confront that issue, then hub dyno is the only answer.

As to the BSAC number.....look at the map. 80 lb/min is off the side of it. So even a lower number is in the region of low efficiency.

[infomotive]

On 24/06/2022 at 7:18 PM, Butters said:

After being a little disappointed with my initial g35-1050 genuine turbo result. To be fair the head started to lift so not all things as they should be.   

I was struggling to crack 600rwhp at 24 psi on an rb26 E85. My other rb26 with old school gt3582 does 600 rear with ease.  

I was hoping for some bigger numbers so ... 

 

I have been watching this closely and it seems very similar to what I experienced, this is however a "Pulsar" version. 

What do you think is going on ?  Surely 27psi on 2.5L cammed engine should be over 600 ?

Or is the pulsar not really a g35-1050 ?

 

 

That PSR turbo has made 1016 hub HP at 41psi with 75 nitrous shot on a customers car on a 26.

It has also made 567kw wheel at 32psi on a 25 restricted by fuel supply. 

Both on manual vehicles.

The above runs are on an auto equipped vehicle with an obviously unhappy converter, and the power runs started at too low an rpm. That tends to cause the converter to be "blown through" on a power run and unreasonably low figures obtained, and overheating of the transmission. A tighter converter would improve this, or start the run at a higher rpm where the converter is more "coupled" to minimize the above effects.

Also, mounting the air filter directly to the compressor inlet will normally result in restricted power and lag.

[Butters]

On 6/25/2022 at 11:06 AM, infomotive said:

The above runs are on an auto equipped vehicle with an obviously unhappy converter

That is a really good point !  I forgot about the auto factor. 

[Lithium]

On 25/06/2022 at 2:04 PM, GTSBoy said:

The 25% loss on roller dynos is not drivetrain. It's tyre-roller interface. That argument is long dead. If we do not want to have to confront that issue, then hub dyno is the only answer.

As to the BSAC number.....look at the map. 80 lb/min is off the side of it. So even a lower number is in the region of low efficiency.

Re: drivetrain loss, don't insult both of our intelligence by creating an argument about semantics.   I feel like it should be pretty obvious that the point I was trying to make is that 80lb/min only being able to achieve 600whp is pretty unlikely.  I purposefully try not to write a thesis breaking down my points when I am giving the audience the intelligence and general not-being-a-dickness credit that they won't misconstrue what I'm trying to say.  

In case you legitimately didn't get what I meant by my post, I'll try and make sure we're on the same page.   A compressor map doesn't show BSAC (Brake specific air consumption, or literally how much power you end up able to make from a given air mass), it shows adiabatic efficiency.  Sure, lower compressor efficiency can have a bit of an effect on BSAC if you've gone off the map and the gate has had to be shut to keep spinning the compressor causing EMAP to get high enough to have an effect on pumping efficiency, but realistically 80lb/min with lower compressor efficiency is still 80lb/min of air.    The BSAC of your typical 4-valve, E85 snorting RB is such that you should be able to make WELL over 600whp through a manual on even the harshest of dynos with that kind of mass air flow.

 

[Lithium]

This is one of the better (but definitely not the only) 900+hp G35 1050 results I've seen.  

If we bare in mind the G35 hotside is not ideally matched to the compressor, generally considered a bit small for it - and that at PR 2.2 it flows about 95lb/min, then this is kinda a "really well working but not an impossibly perfect best case" indicator for what you might expect from Garrett G-series on a RWD platform running ethanol on a Mainline hub dyno.  It fits with my general "1lb/min = 10hp @ hubs on E85" rule of thumb I use, or 9hp @ wheels on an Oz roller dyno.

At the same rate you should expect a G35 900 should be able to support 700whp area on a roller dyno, or near 800hp on a hubber with everything working well.   Funnily enough people already hit that territory with them, too.

[GTSBoy]

But the OP's jigger is only doing 24 psi.

[Lithium]

On 27/06/2022 at 12:30 PM, GTSBoy said:

But the OP's jigger is only doing 24 psi.

Good point. So in the Falcon example it's running near PR 3.2 where the G35-1050 map runs out at 95lb/min, and we assume @Buttersis effectively running PR 2.7 then the map runs out at closer to 100lb/min, or ~5% more flow than in the case of the Falcon above.

Going by that - in the ideal situation it'd be good for up to 1000hp @ hubs on E85 on kill, or 900whp on a roller.   At the same point the G35-900 is capable of 80lb/min  (I'm assuming you got mixed up and looked at the 900 instead of the 1050 compressor map) which as above shhould be good for 700whp/800hp @ hubs.  Still comfortably north of OP.

Even the lowly G30-770 should be good for 700hp @ hubs/ 625whp if the hotside is up to it going by that lot.

 

[GTSBoy]

Ahhah! I just realised I furked up. I dropped a bar off my thinking and was looking at the PR 1.67 territory, not the 2.67 territory.

So I withdraw most of my original point.

[Butters]

so here is hoping the lifting head was losing me some of those ponies at 2.7  

[BK]

On 24/06/2022 at 4:48 PM, Butters said:

To be fair the head started to lift

How do you know this for sure ? As in, how do you know you haven't blown a head gasket, cracked a block or cracked a head ? These things generally happen in my experience before a head "lifts".

[Butters]

On 6/27/2022 at 11:47 PM, BK said:

How do you know this for sure ? As in, how do you know you haven't blown a head gasket, cracked a block or cracked a head ? These things generally happen in my experience before a head "lifts".

Well

Coolant pressure increased significantly under + boost.  Enough to bypass rad cap

Coolant pressure normal under low load conditions and no overheating.

Head off and you can see where it was bypassing the cylinder ring to coolant chamber on both head and gasket.

Head cracked tested and serviced, all good.

Block was only visually inspected, so please god ...  let that be ok

 

You could argue that is a Head gasket failure but it was still very much a complete unbroken gasket. So suggests some stretch on the factory head bolts.

I know others that have had the same as above and not even taken the head off, just put in studs and  continued on for years.

 

[Butters]

So this is a lot to take in ....

 

The housing on the g30 , just mad, not what i expected at all.

Still the g35 on race fuel is not making numbers I want to see