Jump to content
SAU Community

Recommended Posts

And to add to my previous diatribe:

Two stroke engines have no torque [its argueable but generally agreed].

Turbos add torque to a motor in big gobs when they are boosting.

Think about a long stroke motor, it revs slower, but compresses a lot more volume [swept volume is usually greater], then when the bang comes it pushes against a much smaller cross sectional area because the piston/bore is smaller, the motor is 'undersquare'.

A turbo on a motor tricks the engine [tricks isn't the right word but it'll do] into acting like its compressed more volume because its added volume that is pumped in rather than drawn in.

A short stroke motor has less swept area, so it compresses a smaller amount of volume [this doesn't affect its compression ratio, it can still be as high as a long stroke and is usually higher]. And the energy from the bang is transferred to the piston crown over a wider area.

Probably boring to many, and apologies for the OT hijack.

  • Replies 49
  • Created
  • Last Reply

Top Posters In This Topic

god of knowledge :sick:

nah it's good to have stuff lol explained very clearly

quick update car is coming along alot quicker than planned AUTOTECH are awesome they got the old motor out in no time at all which is been sold tomorrow and now i'm actually holding them up cos i'm not picking up the new motor till next saturday when i will also be picking up new radiator and fuel pump

so i think i will actually make the chrissy cruise :P

Edited by Slither

so I take it you naysayers would suggest that the 2.8l Z tune is a 'light' truck motor then?????

:laugh:

no...really...I think as many people as possible should stay with the RB26; that way if a 3l should drop to 5 cyl on the track the driver can hear the buzzing of a 9K rpm RB26 coming up behind them. not to mention that you're doing your part for aftermarket sellers in this country what with parts that either grenade or need replacing when they live at those rpms...cams, clutches, oil pumps, gears, bearings...

then there's the fitness advantage to an RB26. a part flies a long way when it lets go at 9K rpm - even if its flight is impeded by the block - so it's a long walk home, and even longer if it flies in the opposite direction and you have to go pick it up.

slither I assume you know about the pdf FIY guide for rb30 conversions? take your time and it will come together nicely, just don't get frustrated by the little detail things as they make the difference between god/dog installation. sorry if i'm teaching you to suck eggs. are you getting a new rad because your old one is buggered? what ecu are you running?

cheers

Edited by Scooby

yeah i read the rb30 guide nd was about to grab a rb30 block when i came across this http://www.skylinesaustralia.com/forums/in...&hl=rb30det for the price i really couldn't refuse, with buying anything second hand theres always a risk especially when the motor hasn't even been started yet, but the risk can some times pay off and for 1100 if there is a prob it will still work out cheaper than starting from scratch :)

Tom the guy that built this motor is a really switched on block and i feel really sorry for him spending a year buying parts and building an engine only to sell the lot to pay for a split second accident it pays to get 3rd party something i really should do!! been through a similar thing

the ecu i'm running is a link gtst i know ppl aren't to fond of these but once again got it for a steal and the features it offers a pretty sweet, map sensor, launch control, ability to control boost by the factory boost solnoid,

and pete at autotech actually seemed to really enjoying tuning it on the lap top so if he's happy than i'm happy :sick:

and yeah picking up another radiator cos the top hose connection is busted and the hose was been held on a bit dodgy didn't have any drama's but thought since it's out should do away with it and grab another one going to wollongong motorsport centre he's got 3 there 120ea so i'm thinking atleast one of them has to be in good nick

Edited by Slither

also if anyone else needs parts from sydney i'm going up next saturday with the BFV (big f*cken van) so if it's not to far out of my way i'd be happy to do a parts run for ppl

tom's injectors wouldn't be a bad buy or the turbo lol

  • 3 weeks later...

hey scooby,

yeah it seems to be coming along pretty good had a few little drama's with the motor been 4cm taller than the rb25

but it got started up on friday minus exhaust due to the dump pipe not reaching lol apparantly it sounded absolutely nuts :mellow:

motor seems to be the goods was running on all 6cyl with no knocks or anything

now it's just has to go on the dyno to have the link retuned to the new motor interested to see if beats the 25's figure of 211rwk that i ran on that dyno only 2 months ago should cos i'll be running more boost and a hi flow fuel pump now

so yeah coming along pretty good with any luck it'll be on the road for the modified nissan cruise this thursday :O

by the way for anyone interested in this criuse cos they are really good fun been on a few with the MN people there a great bunch feel free to pm for details

yeah currently it's just got the stockie on it which is going to be pretty gay really really nice down low lol but yeah probably run out of puff not far after 5 i reckon, so i'll be pretty mauch losing 2000rpm till i get a bigger turbo thinking gt35/40

speaking of which does anyone know what sort of cost you'd be looking at to get one fitted if you were to purchase a complete kit from gcg (hi mount manifold, ext wastegate, and all hoses)

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

    • 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.  
    • For race cars, this is one part where I find having the roll cage bar having gone through a hole in the floor better than the build it up on a ledge inside... The Merc I help on, the main hoop ends are marked on the car, and the jack is marked... Jack goes under a few inches and lifts one whole side of the car up... Removes that fight for long slim jacks for race car duties!   My biggest issue for the daily drivers I work on, is my jacks don't go high enough. The jacks start out on a few blocks, jack it up, then start a second jack under it on more blocks, and then I can get an axle stand under it. My axle stands are presently in use, and are nearly fully extended. The car is sitting with barely more than a cm of clearance to get the wheel off the studs! Sarah's Kluger is the same, as it has an ungodly amount of droop available in the suspension and a distinct lack of good jacking points!
    • Happy? Yep, my to do list is getting shorter and shorter. Either this light approaching is the end of the tunnel, or I'm about to be hit by a train... Ha ha ha   Also, Duncan isn't that far out of town that you need to make a multi day drive out of it. 😛
×
×
  • Create New...