89rx7vert

I researched but nothing..
my question is if you port you 13b n/a do you
have to port the manifold as well?
i did not think so but the guy that i bought my
ported 13b from said that i have to port it or
it wont run rite...

now i did the swap, and i have been having some problem
with getting it to idle i thought it was a timming issue but i got that
solved but still no idle???

do u think the none ported manifold is causing this?

thanx-

(excuse my spelling and grammer)

rotarygod

iTrader: (1)

No. You don't need to port the intake manifold and I'd generally recommend against it. There isn't much to do and what little that can be done really needs to be done by a person who knows where the problem areas are and how to deal with them. There are some "obvious" looking mods that people do to them that actually hurt performance as not everything works as you think it should. You also didn't state if you have an S4 or S5 and each needs to be addressed very differently but to answer your question you aren't having issues because the intake manifold isn't ported.

89rx7vert

orite koo..
i did not think that porting the manifold had to do with anything, but just making sure.

oh and its a s4 with (what i think is) a first gen gsl 13b engine,
i took care of the intake leak it had and timming, and vacumes are ok,
i just dunno what else it can be?????

glhs0867

I would port the manifolds.. at the least gasket match the ports.

I have ported past the gasket and ported the gasket to match the runners. I would not port the primaries for velocity reasons. I did port the heck out of the secondary ports. For the maximum flow at WOT..

HAILERS

What does no idle mean?

Does it mean the engine will run if you keep your foot on the pedal and stay running like that, but when you let off the pedal it won't idle by itself?

What does it do? Say you get it started and keep it running til the engine gets hot, then let off the pedal, what happens? Dies right off? Struggles to stay runing but the rpms keep dropping and then dies?

Rock hard grommets at the bottom of the fuel injectors can cause large air leaks and keep a engine from idling. They should be soft and malleable.

Josh13B

air leaks especially from the vacuum lines to the TB can cause irregular idle.

also check electrical connections to the battery and CAS, they cause all sorts of problems

NoPistons!

iTrader: (3)

The stock manifold is a well-engineered peice, actually. I thought about doing some work to a spare s4 i have sitting around but after doing some reading i decided not to.

89rx7vert

by no idle i mean it starts up and it runs but when i take my foot of the
petal the rpms drop all the way down and die.

what does it do: if i stay on the gas till it warms up ( takes like 30)
it does the same just dies, but it does feel like it wants to stay on when
it gets warmer but its very litle struggle.



to the TB? trottle body?



[QUOTE][also check electrical connections to the battery and CAS, they cause all sorts of problems/QUOTE]

ill take a look of that too.
thnx

rotarygod

iTrader: (1)

Do not gasket match manifolds!!!! The gasket holes are much larger in area than any other point in the intake runners. All you are doing is slowing the air down slightly and then speeding it back up again. This isn't helping anything. Changing air speed and velocity uses energy. Not tons mind you but something never the less.

Airflow through manifolds is not about max flow!!! This is a very common misconception. It's about velocity. The goal is to have max velocity but still not be a significant restriction. There is really no reason to go larger on the runners. You "might" gain some top end power as making the runners larger will shift the powerband upwards a little bit. This is from tuning (and a lowering of velocity) and not from flow capacity. However with everything there is a tradeoff.

The only thing to worry about where the different manifold parts join is to make sure you have no edges of lips for air to pass. Actually having the lower manifolds at the joints be slightly larger than the one above it for a reverse lip is beneficial. Gasket matching isn't.

HAILERS

A BAC is supposed to try to maintain a 750 idle speed. Yours seems to be not doing that.

When the engine is cold, the water thermowax holds the throttle plates open a touch to get the idle around 1300rpm and as the water temp comes up, the throttle plates gradually close.

But even given that, a engine should idle even if the BAC plug is off. Timing being off can effect it. Vacuum hose connected up wrong can effect it. Leaking grommets at the bottom of the fuel injectors can effect it. Someone having messed with the throttle stop screw can effect it. A fooled with AFM can effect it. Wrong sized fuel injectors can effect it. Turbo inlet duct cracks can effect it. Kinda hard to fix online.

opps a non turbo. Maybe the port job is part of the problem? Maybe just screw in the throttle stop screw a touch til you figure it out.

89rx7vert

bac? Bypass Air Control???

if so where is that located at?

i opened up the screw on top of the trottle body, and put a lil tentison on the trottle cable and i got a kinda idle.

it stays on but it is jumpy from 950 to 1300 rpm..

i will post a vid tommorow so you guyz can get a better idea on
what im dealing with.

-thanx

philly101

my car dose this some time after i have bein drive.

HAILERS

You really need to read the Fuel and Emissions section of the FSM.

It sounds like you have a vacuum leak what with the jumpy idle at 900 up. OR you have the vacuum lines on the front of the dynamic chamber misrouted or the two vacuum lines on the back of the throttle body misrouted or have the air feed to the oil injectors mishandled somehow.

BAC's on the left side of the engine. On non turbo it's non adjustable, just needs its electrical pulg attached. See FSM.

The ECU self advances the timing at about 1100 rpms, so at that 1100 area the rpms will jump up a couple of hundred more.

89rx7vert

thanx man i havent thought about reading up the fuel n emissions.

and now that you mention the vacumes to the oil injector maybe not properly routed , because
i have no oil injectors im running premix and the air lines to the injector need to
be blocked off? i dont remember what i did with them.

and also from looking at FSM i notice that my egr was missing????
and i did some research and i understand that there has to be a block off plate if the egr is removed?
do u guys think this may have something to do with my problems?