How big is a 99.5 intake cover opening?

[Tail_Gunner]

I'm going to upgrade my air induction system. I can't do a turbo upgrade at this time because of my need to change injectors this summer. What I plan on doing is taking my early 99 intake covers off and putting 99 1/2 intake covers on. Currently a reducing adapter boot connects the plenum to the intake covers. As long as the center of the intake cover opening remains the same, a expanding adapter boot should make transition from my current intake plenum. Supposedly this sort of mod has been done several times already. It should help the engine breath a bit better and also make things go a little faster when I do get around to upgrading the turbo since the intake covers portion will be already done.

My question is this: Is the opening of the 99 1/2 intake covers 3" in diameter? I have to measure them, but I think the outlets on my intake plenum/"Y" manifold are 2 3/8" in dia. So if I have the numbers right, a 2 3/8" to 3" adapter boot/connector will hook it all up.

I have a new MBRP T-304 stainless exhaust coming from ITP Diesel and plan on doing the two at the same time. That way I only have to unass the downpipe from the turbo but one time.

 

[whatabudro]

In theory it should work but I have no experience with an early 99 so I'm not sure. What I do know is that there is no more than 1/4" space between the y-pipe and the intake plenum, with the total boot length of around 2.75"+/- (thats a complete guesstimate). So your adapter booter will have to be pretty compact in size.

When you upgrade your turbo are you going to be upgrading the y-pipe and intercooler pipes to the 99.5 setup or are you planning are sticking with what you have? I thought there was a limited source of aftermarket turbos for the early 99's?

 

[Tail_Gunner]

When you upgrade your turbo are you going to be upgrading the y-pipe and intercooler pipes to the 99.5 setup or are you planning are sticking with what you have? I thought there was a limited source of aftermarket turbos for the early 99's?

There isn't jack s**t available for an early 99 without changing the up-pipes, "Y" connector, turbo, pedestal and plenum. So that'll be the route I have to take. For now, I'm leaning towards a HTPS turbo but that'll be a while. Like I said, gotta do injectors first.

I'm planning on doing the Stage I single shots from Bean's with a reflashed PCM from DP-Tuner. With the MBRP 4" and my little induction upgrade, I should be :ZigBang: Even with my lil' early 99 turbo, it'll move. It'll do 28 psi with Jody's econo tune.