boostmotorsport

Its an 87 T2 J spec 13bt, and the relevant current mods are as follow

Walbro pump
SAFC
800 secondaries
RB 3" turbo back
intake and CA box
starion FMIC
ported polished TB with 2.5" inlet
bonez clutch
elec fan
guages

And I pan on adding

ported inlet and WG ser 4 turbo
manual DIY boost controller set to 10 lbs
NX wet n20 kit plumbed with 2 foggers into the upper manifold runners tuned for a 50 shot, to use in 3rd and 4th gear.

What do you guys think, and please be specific
Thanx
Fred

mazdaspeed7

The juice is going to give you problems with boost creep. The extra exhaust volume from the N20 will raise the boost by 2-3 PSI at least. The wastegate simply cant hendle the extra volume. Especially with an S4 turbo. I would spend a little more money and upgrade the whole turbo, even if just to a S5 stock with ported wastegate. That *should* be able to keep the boost reasonably when youre spraying.

boostmotorsport

the WG on the ser 4 turbo I will be puting in tomarow has been ported very large, about 1 millimeter smaller than the door. Also when I spray I will tune down the boost 2 lbs. Think thatl suffice?

mazdaspeed7

It might work, but I still think your boost is going to creep. I would say just be careful, since Im sure youre going to do it anyways. Turn the boost controller way down, and see how much it affects boost before you really start messing with it. And remember to retard your timing a little for the juice.

fc3s.org

I agree with Mazdaspeed7. The boost will creep with the bottle on it. I would get ahold of a S5 manifold and turbo and port the crap out of the WG, then run a boost controller. Definately tune it on a dyno to make effective use of the AFC and whatever you plan to use for a boost controller. I would also include 2nd gear on the bottle, but that is just my personal preference

mazdaspeed7

I was talkign to someone with a S5 TII with open exhaust, boost controller, etc. His controller was set to 11 PSI. On the bottle he was creeping to 15-16 PSI. S4's are worse abotu boost creep.

BLUE TII

iTrader: (9)

I believe it is not just the single wastegate on the S4 that causes the boost creep (mine was ported beyond huge w/ big flapper seal and still crept). From what I've read S4 has .8 AR and S5 has 1.0 AR on the exhaust turbine. Still, S5 lag isn't much worse because of the S5 DIRECT exh. mani, so w/ 3" exhaust I imagine it would still be instant boost! Upgrade to S5 if you can...Ian