Julian
Hi guys,
In an effort to stop my cars exhaust smoking I am looking to pull the head, replace valve stem seals and do a pcv job. I've already replaced the turbo, and car has good compression, so want to knock over the two things I think may be causing it. People have started commenting on the smoke!
So it's not an entirely boring exercise, I am thinking about doing the NA intake, throttle body, 960 throttle plate upgrade while I'm at it.
I've done some reading on it, but still had a couple of questions:
- Does doing this require any kind of ecu tune? I imagine that a larger throttle body will result in more air entering the intake at a given throttle position than my car is used to for example. And will the ecu adjust fuelling for the extra air? I have standard injectors in my 850R (but have a set of greens in the garage should I need them).
- I'm considering dropping the head at a cyl head shop for the valve stem seals job, as I don't want to pull the lifters apart etc. Is it worth getting them to machine out the intake ports on the head to match the airway of the manifold, or is this likely to be a negligible improvement?
Cheers!
timbo
I fitted n/a cams and throttle body to my old 850t5 but just bored out the turbo intake manifold to suit.
If you change the injectors you will need a tune though, but the ecu will compensate for the n/a throttle body and cams adequately.
Get a Dremel and diy the port match probably not worth paying the head shop to do it I thought you would need to port the intake not the head but I only did my exhaust manifold when I did mine.
Some advice:
Budget for a vrs kit and head bolts
Get the head skimmed/surfaced while it's off
Check the rings with a feeler guage while you have the head off as most 850s have blow-by at this age and it's easier to chuck some rings in it while the head is off
Julian
Ok thanks for that.
I'm probably not planning on cam swap, just intake manifold and throttle body. I already have a 3" turbo back exhaust, larger turbine housing and the "japan" exhaust manifold, so figured I might as well hit the intake side to try to improve flow a bit there.
I'm not planning to install the bigger injectors unless they're needed for the more air flow. I don't mind doing small air flow mods but want to keep the important things like boost/fuel flow pretty standard for reliability.
I just thought that if I get an NA intake manifold with larger runners that they would then end up being larger than the ports in the turbo cylinder head? Ie: the head ports would be a bit of a bottle neck that I might be able to sort out by machining them out a bit.
timbo
Pretty sure the ports on the manifold are still smaller than the turbo head there's this video of a guy in the USA port matching the n/a intake to suit his 850r
Rob
NA and turbo manifolds are the same casting. The only difference is the throttle opening is larger on an NA. You can swap the manifold if you wish or bore the turbo manifold out. Either way works fine.
You will not need to retune for this mod. It is very minor and the ecu will handle it just fine.
Ex850R
Who knows which cam to put in? Intake or exhaust? Or both?
Put green injectors in anyway. With your other upgrades it will help. Refurbish them though.
Porting is not needed except turbo out.
timbo