Jump to content
SAU Community

Recommended Posts

My rb26 is extremely laggy, makes about 12 psi at around 5500rpm from memory, checked everything twice, thing is the compression is down, ranging from 135-118, would this be the cause of that amount of lag? only other thing that im unsure about is that its got split dump pipes on it and have never had anything to do with them

cheers

Link to comment
https://www.sau.com.au/forums/topic/363259-rb26-lag-compression/
Share on other sites

Most lag issues ive seen are because of air leaking from the induction side of the engine somewhere between the turbo's and the throttle bodies. I recommend blocking the hose from the twin turbo pipe to the intercooler with a plug and then pumping up the intake manifold with an air compressor and checking for leaks. You will spot most leaks with just a few PSI of pressure but you should pressure test to about 10psi above your target boost pressure.

If you find any leaks you should re-set your actuators to stock positioning, or you will end up overboosting on your first test drive and break off turbine wheels.

ill check to see if its around 5mm duncan, yeah i blocked it up found a leak, fixed it and it made bugger all difference, also found an exhaust leak on number 3 cylinder from head to manifold where some champion had half broke the stud but i havnt had the car back together since finding that but i cant see how that would make that much of a difference really

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

    • Well you could certainly buy or build an enclosure for a pod in that corner of the bay. It is absolutely vital that there is a nice big opening to let cold air in to it from the front or underside, otherwise it will just pull air in around the edges from the bay, and if that air is hot, you gain nothing from enclosing the pod. There is lots of good evidence around (including on here, see posts by @Kinkstaah for example) showing that pods pulling hot air from the bay is only a problem when you're static or slow in traffic, and that as soon as you get the car up and moving the air being grabbed by the pod cools down. Although that will obviously vary from car to car, whether there is a flow of cold air to the pod or if it all has to come through the radiator area, etc etc. Obviously, the whole exercise requires as much thought as anything else does. Doing the lazy thing will often end up being the dumb thing. The stock GTT airbox has a cold air snorkel to feed it from over the radiator. Shows that Nissan were thinking. The GT airbox is upside down compared to the turbo one, yeah? Inlet at the bottom, AFM/exit on the lid? That might make it harder to route the turbo inlet pipe using the GT airbox than a turbo one. That would probably be the main reason I'd consider not using it, not that it is too small and restrictive. I'm looking at a photo of one now and the inlet opening seems nice and large. Also seems to have the same type of snorkel that the turbo one has. Maybe all that's required is to make a less restrictive snorkel/cold air inlet, perhaps by punching down through the guard like I did.
    • Also seen this as an option 
    • I get you, we’ll see I’m aiming for 200ish kw now and hopefully 300rwkw down the line after some upgrades maybe like headstuds, E85 flex fuel etc  so trying to make it final for that now, I can get a GTT airbox for $280 so it’s not too bad but not sure if there’s better ways to spend that money. I seen online they say pod filter which isn’t enclosed isn’t good especially for a plus T.      hard to say what to do
    • Meh. How much power can you make from a +T anyway? I wouldn't have though it would be enough to challenge the airbox. It's not as if it's tiny compared with the turbo one. As to putting a pod in a stock airbox .... it's not the filter element that would be restrictive. It would be the air inlet to the box that would be the narrow point, which you could open up regardless of what element was inside. On my R32 I opened up the sort of triangular opening in the bottom front corner of the box, deformed (heated, moulded) some 4" stormwater pipe to fit to that opening and punched a 4" hole down through the inner guard to the spot where the stock intercooler used to be. This was purely in the search for a cold intake, but you could do something similar if you need to open up the inlet side of it. The AFM tube size is the same for both NA and turbo, so the outlet from the airbox is same same anyway. If you're going to do the right thing, then an aftermarket ECU won't care about the AFM (ie, you can get rid of it). But even if it was still there, people pull >300rwkW through them all day, and I suspect you won't be going there.
    • R34 RB25de Neo by the way ^ 
×
×
  • Create New...