GT3076 V G30-770 dyno results back to back - FJ20

[Gareth87]

Just wanted to post some info on my back to back dyno result with my old GT3076 against a new G30-770.

I struggled to find info on the 30-770 mounted on a 4 cyl, but also thought it might be of interest to those of you looking at this size turbo for a 6cyl.

My target with the new turbo setup was to reduce inlet air temp and hopefully make a little more power and with any luck gain some response. The old GT3076 made good power but maxxed out at around 22psi, we tuned to 24psi but only made very small gains which prompted the upgrade.

Nothing changed on the engine setup other than turbo swap. Everything else remains unchanged from the last tune 7 months ago. Dyno bed length and strapping were also exactly the same as well as the tyres which I swap over to road tyres from Semi slicks just for dyno work.

Engine spec is a built FJ20, pistons, rods, head porting, big cams etc (let me know if you want exact spec).

First thing to note was the new turbo had slightly different dimensions and needed the flange cut and re welded on the exhaust manifold to give clearance between the head and comp/exhaust housing. Exhaust flange is also Vband which needed re welding from old 4 bolt flange. All easy stuff.

Matt at PITS has tuned my car for 15 years and quickly started working through the boost levels.

First thing to note was that the new G30-770 came on earlier even though its got a higher HP rating. We gained about 300rpm in spool and power was up immediately on the old setup. Not by miles, but it was above the 3076 and the same boost.

The biggest gains started coming with more boost and made its biggest jump above 24psi which is what the compressor map suggests.

Overall, very happy with the result. The new setup made 41hp more than the 3076 with only 2psi more boost and we also gained response.

 

Dyno sheets attached, the 2 best runs with the 3076 were 495 and 507hp, but Matt pulled it back to 495 as inlet temps were over 80 deg C.

New turbo made 536hp with inlet temps around 60 deg C. 

Look carefully on the dyno sheet and you'll see the old vs new lines.

We didn't tune further as it has a cometic head gasket which don't have the best rep and we were getting close to the limit of the coils. 30psi should see closer to 600hp with any luck.

If anyone wants some more info on anything, just let me know!

[Dose Pipe Sutututu]

Nice work! Chill down the intake temps down and you'll make more power.

Those intake temps (my personal opinion) are quite high. 

[Butters]

Do i read correctly you gained about 250rpm faster spool and made more power ?

[Gareth87]

@Dose Pipe SutututuYeah inlet temps are still high.. not sure why. Might have to go to a plazmaman cooler. Currently running a 600x300mm mishimoto core.

@ButtersYes, 300rpm earlier spool and made more power. G series turbo do seem to do what they claim!

[Kinkstaah]

So we're comparing red vs blue lines here? Pretty much in line with what people expect.

I was under the impression one of the big draws of these turbos is that they were physically smaller than their GTX predecessors. Is this not the case given what you've said about it fouling on the head?

[Dose Pipe Sutututu]

On 11/07/2022 at 5:01 AM, Gareth87 said:

Yeah inlet temps are still high.. not sure why. Might have to go to a plazmaman cooler. Currently running a 600x300mm mishimoto core.

Even a HDi GT2 core would do wonders. I'm not a fan of those Mishimoto cores.

[GTSBoy]

Yeah, Mishimoto seems to be a dirty word. Their radiators are suspect too.

[robbo_rb180]

Thank you for sharing this info.
Get those intake temps down and will see even more.

Whats the difference in drivabilty? Currently deciding between GTX and G series  

[Kent46]

Awesome back to back data 👍 and talk about a sleeper! With intake temps that high I would also consider a nice partition around the intake as well as a larger volume cooler as suggested. 

[Gareth87]

@Kinkstaah just on the dyno sheet with 5 different power reading, the 495hp run was with the old turbo. You can see where the line comes on later.

They are smaller, yes, but marginally and it was the shape of the housing that were the problem.

@Dose Pipe Sutututu

Definitely keen on a better cooler, the mishi core certainly didn't impress me. I did a back to back run with intercoolers last year as well going from 450mm autobarn core to 600mm mishi core and made almost no difference.

@GTSBoy

Agreed

@robbo_rb180

Drivability is chalk and cheese. This is lightyears ahead. The torque increase even on marginal boost is so much nicer at low revs

@Kent46

Thanks mate, I've worked hard on it over the years to build a tidy and fast street car, i will shroud that filter at some point, I've got a few ideas about using a remote airbox. I'll get onto it!

I think the intercooler is the biggest issue for air temps though.

[FJROLA]

Hi Mate 

Have you sorted the intake temps out yet? 

[discopotato03]

This takes me back .

I mucked around with S1 Bluebirds through the 1990s and I also went down the FJ20ET road .

Mine was basically a DR30RSX in a 910 shell , it had the DR30 R200 rear end grafted in as well .

Cooling is a pain with them . I used an R32 GTR radiator and a very early Plazmaman intercooler . Arthur Jackson went to a lot of trouble to basically reconstruct the radiator support panel to fit that intercooler . It needed the OE Bluebirds bonnet catch section removed and a Datsun 1600 dog cock style catch system fitted . You have to cut a section out of the underneath of the bonnet and weld a piece in to take it . All worked really well . 

A bit OT but the best master cylinder system I found was to get a 910SSS booster and get it opened up and re orient the outer half 180 deg from std . That way you can fit a JDM Nabco or Tokiko master , I think they were 1 inch . The Australian booster is garbage and the PBR/Girlock 13/16 master worse . I think I had the external proportioning valve but eventually went to a Rally style adjustable one . Most of the OE stuff is probably unobtaneum nowdays , I was lucky enough to rape front cuts for the small stuff after others had bought the Z18 and box . 

 

Edited April 11, 2023 by discopotato03

[Dose Pipe Sutututu]

Thought we would never hear from you again @discopotato03

[FJROLA]

Mine is in a KE11 Corolla. 
 

so packing is tight to say the least. Pwr barrel cooler will work wit some work so that seems to be the best best option as I don’t want to cut up the front of the car too much. 

[Gareth87]

Funny this thread has resurfaced.. I am going to do a log recording when I get a chance and I'll take the front bar off vs standard. I want to see if the added airflow changes things much. If so, I can put at least part of the problem down to airflow.

[discopotato03]

I still have my R33 , it sees the light of day about twice a year .

[discopotato03]

Yep , airflow through a 910s engine bay isn't brilliant .

Factory standard with the carburetted L20B they used elec fuel pumps to get around fuel boiling in the carbs and hard pipes .

I think the issue is convincing warm/hot air to flow down around the gearbox and out underneath . The two factory cars with FJTs from memory were R30 Skylines and some S12s , both of them had fairly long engine bays particularly R30s . The FJ looked weird in my DR30 - being so far forward . 

You probably don't want to hear this but the two biggest issues with 910s are cooling and rear suspension woes . I solved most of the cooling ones but with a lot less power than you have . The std 4 link rear is pretty hopeless , with any body roll the diagonal top links pull the inside wheel forward and makes it try to rear steer .  This would have been part of the reason why S1 Bluebirds had such soft sloppy rear suspension bushes , the S3s were better . Mine was aggravated by the Detroit locker I ran because I couldn't afford a Nizmo H190 clutch LSD . Highly amusing in a straight line . I remember out running some clown in a 351 XB up the old Woronora bends west of Sutherland one afternoon . Detroits are great if all you want is grip but they will crack/tear the rear suspension body mounts of cars like Bluebirds . It's also funny taking off from the lights with D lockers if both sides aren't locked . First all the drive comes through the locked side then the other side lines up and engages with a crash that makes you think you've broken an axle . My first attempted fix was a one off 5 link Panhard system , it didnt rear steer as much but to get it to work properly would mean raising the top links and housing them in "boxes" where the rear seat pan is . Some classes of rally BDA Escorts allowed this and it works well from a grip point of view - hardly practical in a road registered car . I knew of one Rally Stanza this was done to and it worked too well , as in the rear didn't want to unstick which doesn't work on the dirt .My second try was to graft in the whole DR30 R200 semi trailing arm IRS setup . Again better but heavier as well . I look at Datsuns semi trailing arm system as half way between live axle and proper multi link IRS . Its issue is that you get significant toe and camber changes as the suspension rises and falls . It was more comfortable - and who doesn't like the R200 diffs shafts and brakes after Astrayan content garbage .

Anyway Nissan solved many of these issues with S13s and later . I'd had enough of 80s issues , with the DR30 it was horrible drag link steering and no spares for steering boxes . I bypassed the S series and went with a GTS25T .

 

[morboost]

not a bad result wouldn't be much in it verse a gtx3076r.

from memory the aus delivered r30 irs subframe bolts in

[discopotato03]

No they don't .

The cross member mounts aren't there and neither is the rear R series diff mount . The closest thing you can get is the 200B SSS rear end . 

To fit this system up to an Australian 910 you have to open up the tops of the rails . From underneath the box sections the outer skin has the relevant holes but the inner doesn't . I chopped the rear pin mounts out of some early type Skyline at a wrecker . Arthur Jackson machined them to sit in the opened box section and welded strengthening webs inside the rails . The X member mounting studs were I think 1600 type with the tapered shank . JDM 910s and R30s have the studs welded into the rails . JDM 910s have a different body cross brace to ours and the R series diff is suspended from a single horizontal bolt . Mine used a moustache bar that Stuart Wilkins used to make and had vertical bolts that went through strengthened sections of the boot floor - from memory . I think that bar is still here with urethane bushes .

The 910 or 200b SSS rear setup would be lighter and the struts would line up better .

Funnily enough Australian shells have the mount for the IRS type hand brake cable clevis . 

Back in the day I tried to sell my IRS FJT'd Bluebird fully engineered for $7000 , no takers . Everyone though they could do it cheaper . I sold most of the bits out of it and the last time I saw that shell it was on the back of a truck with the crane boom through the roof . 

 

 

[discopotato03]

I forgot to add that SSS 200Bs had drive shafts with hooks type uni inner joints I think similar to a K or Z .

Pretty sure 910SSS had pod and CV joints , and an R180 diff . Probably similar to Aus spec MR30 2.4E .

DR30 of course had the larger R200 and shafts and larger solid rear brakes . Their R200 LSD has less plates than the Nismo and a spacer . To make better simply remove the spacer and fit a full set of plates .