Jump to content
SAU Community

Recommended Posts

  • Replies 58
  • Created
  • Last Reply

Top Posters In This Topic

The hybrid turbo built by Matt and others cost around $400 I thought (mainly for machining - use an standard R33 Turbo; the exhaust housing of a VG30BB turbo, and a T04 compressor wheel).

This is a budget upgrade as good or better than some of the $2000 hyflow options.

Enrico,

I've also noticed stocker RB25's holding together with bigger injectors at higher power levels.

When an injector is pushed to its limits the spray pattern is affected. Not all injectors may be affected it may only be one that starts stuffing up and may not stuff up straight away either.

This will hardly show up on AFR's as the AFR's are averaged out over the 6 pots.

Without good fuel atomisation you get a crappy burn/lean out hence why possibly detonation occurs which sends combustion temperatures through the roof eventually smashing ring lands. This is also why sequential injecton makes more power over batch injection, better fuel atomosation = better fuel economy & power.

I think.. :(

Enrico,

 

I've also noticed stocker RB25's holding together with bigger injectors at higher power levels.

 

When an injector is pushed to its limits the spray pattern is affected. Not all injectors may be affected it may only be one that starts stuffing up and may not stuff up straight away either.

This will hardly show up on AFR's as the AFR's are averaged out over the 6 pots.

 

Without good fuel atomisation you get a crappy burn/lean out hence why possibly detonation occurs which sends combustion temperatures through the roof eventually smashing ring lands. This is also why sequential injecton makes more power over batch injection, better fuel atomosation = better fuel economy & power.

 

I think.. :(

I'm with you Joel.

Some other ideas:

Maybe the pulsing of the injector starts to get chaotic at say greater than 90% duty cycle, or at even lower duty cycle but when it has high fuel pressures and you get insufficient fuel when under high load for longish periods like when winding up to 180km/h in fourth.

Maybe by raising fuel pressure (via Malpassi reg for eg) you also reduce flow to injectors as higher pressure for the same given fuel supply = less flow according to flow dynamics I think. But some people say that with big fuel pump like Bosch 044, the fuel supply presssure and flow is so huge it should be OK.

Maybe by using a reg to give you high pressure you also cause differential pressure drop across rail from one side to the other or within the rail and say cyl 1 or 6 gets less fuel than others but as Joel said it won't show up in average A/F ratio out the tail pipe.

With big injectors, you get high flow at low pressure which I think is better and it gives the right spray pattern and even fuel supply across rail.

BTW RBVS, Joel also might know more about rebuild options as he's doing one now for RB30.

I think of it as an injector having an efficiency range + or -.

When you get out of the efficiency range it simply starts dumping the fuel in not spraying it.

Hence why SK states the RB injectors don't have trouble with was it +15% extra fuel pressure?!?! I can't rememeber. He's said or typed :( it a few times now.

+ the fact of if the injector is running a high duty cycle it is obviously going to valve bounce if you like (Tims words).

yea i was thinking about what you said with cars with stock injectors dont seem to last. Also i think it is the spray pattern not covering evenly , hence other spots on the pistons not being cooled.

freebaggin: i have been looking into the rb30 bottom, just have to check iv got room to move 30mm up.

yea if anyone can give a price or advice for building a 25 or 30 bottom end would be help full, just the build as im going to try slapping the head back on and dropping it back in to keep cost down.

Dean, might I suggest saving for upgraded injectors and not trying to push the stockies to mid/high 200rwkw levels! Take it from me mate, an extra 1k or so (for 550's) now is better than replacing a piston or two down the track.

Do a search and see how many RB25DET rebuilds have occured with stock injector, bigger turbo, GTS25t's. I got away with it for a while. I "may" have got away with it for longer with a very conservative tune? I use to post on here supporting the 044, reg and higher f/press combo. Not anymore!

Of course if you'd like to go the whole hog, do forgies, lower the comp ratio and go for big boost... then go for it mate! It's heaps of fun :D

yeh matty, ive had a big think about it, and everytime a rb25 ringland goes, everyone blames it on the tune. only recently did u guys think it could have somethin to do with pushin the stockie injectors too far. this could definately have adverse effects on spray pattern.

u had stock inj when engine went

boostd was the same.

there are probably many more cases.

needless to say, i think once my car is retuned, ill keep it like that for a while then think about a bigger turbo.

cyas

G'day gobiz, my turbo is a bit of a bitza. Sorry I can't give you any hard and fast data on it :D

Here's what I do know:

It's a plain bearing Garrett based T3/T4 with a T04E 0.60 comp housing and a 0.64 exhaust housing. The exh wheel is quite large and it's been backcut. The exh housing has been machined out to fit. It has what those in the know stated as a very big comp wheel squeezed into the T04E housing.

On my engine the turbo has damn near the same response as a HKS GT2835ProS. With a touch more power and a quite a bit more peak torque (similar boost). Same dyno same day.

whatsisname, this turbo wouldnt be suitable for rb20 would it? i dont care if boost doesnt come on till 3500-4000 at the moment. mite be swapping till rb25 in the future. is the exhaust housing similar to vl turbo? or just a .64 sized t3 off the shelf item? what boost are your running?

Matty, is your turbo the same as Boostd's (Mat's). If I recall the specs on his were as follows:

used an standard R33 Turbo; the exhaust housing of a VG30 BB, and a T04 compressor wheel. Vtrim Comp with groove in comp cover snout. Exhaust bored out to flange.

machined at Russel Engineering.

If not, bo you have any info on how your turbo compared with Mats

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...