FJ20 turbo choice - over 500whp

[Gareth87]

Hi all,

Been back at the dyno a few times in last months.

Story is.. My FJ20 makes 500hp on the Pits dyno but its making loads of air temp. 70 deg after a 4th gear run. Went from a 450 cooler core to 600mm and made very little difference. Made about 520hp at 24psi but we pulled it back for safety. Its making over 10hp per PSI so turbo isn't showing it's maxxed.

Air temp issue needs to be solved so it's either try a plazmaman core or update the turbo with the theory being the 20yr old GT3040 is making heat.

Open to suggestions here but thinking an update to a Garrett G35/900 but not sure if this is going to make it lazy or new age turbo might even improve response.

Want to eventually see 550 to 600hp

So.. turbo or cooler? If turbo.. is the 35/900 in the ballpark?

[robbo_rb180]

G30-660 or 770 would be the go. Heaps more efficient but a quality intercooler core will help IAT consistency.
 

Edited January 6, 2022 by robbo_rb180

[Duncan]

Good on you still pushing a FJ20 hard

A 20 year newer turbo is way better, either same power with more response or more power with the same response. They are also more efficient and will produce less heat at higher boost than olden day turbos

[Gareth87]

Thanks mate!

This is my thought, while it still makes good numbers with the old turbo, I'm sure that 20yrs of tech would see an improvement!

Just slightly concerned about the heat thing. But as many people use chinese intercoolers and make good numbers, I'm feeling like a big part of the problem is turbo. 

I would be very keen to see any 4 cyl engine running a 35/900 to see where it comes on and makes power etc.

[Kinkstaah]

.... whats your intake/engine bay look like?

E85 (in dyno situations) does reduce IAT's on repeated pulls. Most people like to run it if you aren't already. I saw a back to back jump after literally dyno tuning on E85 then putting 98 in the tank and running the car.

(I didn't get to 70C IAT mind you, and this was with a return flow blitz SE intercooler)

[GTSBoy]

Don't just ask the question. Put a temp sensor in the hot side pipe and find out what temperature the turbo is producing.

*(But otherwise, all advice above is also valid).

[Gareth87]

Yep. Good point..

I'll rule out what i can first. Yeah a sensor to pre intercooler is the go.

[Kinkstaah]

I mean... what air exactly do you think your pod filter is sucking in?

You will see changes if you move it a little out and box it in, and duct it/heatshield it. I have been doing science on it as of late and you should too (as above :p)

[hattori hanzo]

going from a HKS cooler to a plasmaman i went from an average of high 40/low 50 degree IAT to low 30 IAT.

 

This is all after several laps around a circuit.

I also found less fluctuation the HKS cooler would spike harder quicker where as the plasmaman takes longer from the IAT to increase.

[robbo_rb180]

On 1/7/2022 at 8:05 AM, Gareth87 said:

Thanks mate!

This is my thought, while it still makes good numbers with the old turbo, I'm sure that 20yrs of tech would see an improvement!

Just slightly concerned about the heat thing. But as many people use chinese intercoolers and make good numbers, I'm feeling like a big part of the problem is turbo. 

I would be very keen to see any 4 cyl engine running a 35/900 to see where it comes on and makes power etc.

A local workshop is about to put a g35 900 on an ej25 and I know he will put results up @Plattsy has shared his results of  G30 on ej25. I think it made over 410kw at the wheels on e85. 

[Gareth87]

On 07/01/2022 at 11:55 AM, Kinkstaah said:

I mean... what air exactly do you think your pod filter is sucking in?

You will see changes if you move it a little out and box it in, and duct it/heatshield it. I have been doing science on it as of late and you should too (as above :p)

I understand that engine bay air is going to be hot, which is why my next avenue will be to build an external airbox and also add a Sensor pre intercooler to find out exactly where the temp is coming from before spending thousands.

 

On 07/01/2022 at 2:07 PM, hattori hanzo said:

going from a HKS cooler to a plasmaman i went from an average of high 40/low 50 degree IAT to low 30 IAT.

 

This is all after several laps around a circuit.

I also found less fluctuation the HKS cooler would spike harder quicker where as the plasmaman takes longer from the IAT to increase.

This is very interesting, heaps of people have said that cooler temps are drastically cooler with a plazmaman core, so it may be something to visit once I find out what the sensor says.

Knocking 20 degrees off is huge!

On 07/01/2022 at 5:51 PM, robbo_rb180 said:

A local workshop is about to put a g35 900 on an ej25 and I know he will put results up @Plattsy has shared his results of  G30 on ej25. I think it made over 410kw at the wheels on e85. 

Keen to see how that goes!

 

Surely there must be a few 4 cyl guys running a G35-900 around...

[discopotato03]

Bluebirds always had issues with hot engine bays , the std L20B needed an elec fuel pump to circulate enough to stop fuel boiling issues .

They don't appear to have good airflow through the engine bay meaning down past the transmission and out underneath .

The FJ20ET takes up a lot more space than the L Series and this doesn't help .

[Gareth87]

On 07/01/2022 at 11:03 PM, discopotato03 said:

Bluebirds always had issues with hot engine bays , the std L20B needed an elec fuel pump to circulate enough to stop fuel boiling issues .

They don't appear to have good airflow through the engine bay meaning down past the transmission and out underneath .

The FJ20ET takes up a lot more space than the L Series and this doesn't help .

Interesting you say that, I have noticed hot spots in the engine bay over the years. I have done a lot with heat shielding which seems to have made a difference. Saying that, engine temp has never been an issue though luckily.

I'll get the basics addressed asap and see what effect it has.

New turbo is pretty tempting though haha. sucks having mates with fast cars egging things on!

[SiR_RB]

6266/6466 would be nice

[discopotato03]

Many years ago I had an FJ in a Ser 1 TRX .

Was a major operation to reconstruct the rad support panel . I used an R32 GTR radiator with DR30 fans and an early Plazma intercooler . Arthur Jackson did the fab work inc the cut and welded bonnet to take a 1600 dog cock style bonnet lock .

Turbo wise a GT3040R or as some say GT3082R is definitely old school . The HKS version worked better than the Garrett marketed one , the difference was the 50 trim compressor in the HKS compared to the 56 trim one in the Garrett marketed version . 

 

[Gareth87]

So I have been doing some research into the turbo sizing and it's looking like the G35/900 is going to be a good fit for the engine combo.

It's also got a T3 housing so I can leave my manifold as is and just change to V band exhaust.

The biggest issue I've got is that going with that turbo seems to be best guess. I haven't had anyone overlay a compressor map yet or have many results to speak of. 

My main concern is increasing lag and loosing response. I don't suppose anyone has the compressor maps and is able to give me a ballpark pro/con over the rev range and will it be a significant improvement to power and usable power?

Current turbo - Garrett GT3040 - 0.82AR

Proposed turbo - Garrett G35/900 - 0.83AR

Engine limiter at 8300rpm - Current max boost 24psi

[r32-25t]

You could go the g30 900 and then you’ll have the same size exhaust wheel as your current turbo and a smaller front wheel then your current turbo and still have the ability to make a lot more power 

[Gareth87]

A few people have suggested the g30/900.. i was concerned with it being not a big enough step forward. I don't know a great deal regarding compressor maps but I don't suppose you would have an overlay of the maps between the 2 turbos and how they would stack up? 

[r32-25t]

It depends if your current turbine is a restriction or not, if it is go up to the 35, it’s it’s not then stick the 30. Also the g30 turbine wheel will flow more then your gt30 one
either way you go the compressor wheel is going walk away from your current turbo 

[Gareth87]

Interesting. The 30/900 looks right on paper but weather it gives me enough headroom is the question.

I dont have a pressure sensor in the exhaust manifold so I won't know if I have a restriction unfortunately.