Hey everyone, I have an 89 Turbo II and used to have an 87 Turbo II. I have customized both, yet with the S5 I notice there are huge differences. When upgrading the fuel system to run a pararail system I noticed I cant use the S5 fuel rails. Had to get S4, now I noticed I can't put the S4 rails on the S5 Lower Intake Manifold, different bolt setup.

Now my question is: Will the S4 Turbo II Lower intake manifold bolt up to the S5 block? If so, does anyone have the S4 intake manifolds for sale? Lol.

If anyone is confused about what I am talking about yet think they can help, I will provide pictures.

 

the rails are interchangable, if they're not fitting then you're not installing them right.

the only differences between the manifolds are the S5 has slightly larger port runners, the bolt pattern is a little bit wider for the LIM/UIM connection and the rear runners are about an inch longer so you also need the S5 intercooler to fit the intercooler on the UIM properly.

so, the manifold isn't a direct bolt on, nor will it fix your fuel rail issue.

 

the long through bolt for the s5 is longer than on the s4. the s5 manifold is physically taller. by my estimation the runners are longer and the plenum chamber is a little bigger. the actual ports and flange on the LIM are different from the s4. If you compare the LIM gaskets between series you'll see what I mean.

 

you can port match it and dremel the UIM outer holes to make them fit one another but it still disregards that the fuel rails bolt to the block and LIM exactly the same way on both series motors.

 

I have a FMIC so no worries, I know the ports are a little larger on an S5, but really big differences? We can argue that all day. Ill post pics so I can prove the rails are not interchangeable. More interested if I can just buy S4 Upper and Lower intake manifolds and bolt them up to my engine. If minor modification is involved, well that is what american-ingenuity is for.

 

yes, i would like pictures of the issue since i have an S5 at the shop right now with an S4 rail on the LIM without having modify anything.

 

you can put s4 t2 rails on a s5 t2 lim...i have done it. you just need to put a few washers as spacers between the rail and lim.

 

ah that's right but iirc it was minimal, i think i used 1 washer on each foot.

 

These are pictures of my problem. Consist of:

S5 manifold, S4 fuel rail

the dirty fuel rail is the S5 fuel rail.

 

that's because you have a n/a secondary rail there...(why does this seem to be a common problem lately?)

S4 rails are all aluminum
S5 rails are all steel molded
S4 n/a secondary rail has the FPR bolted to the side with 2 phillips screws
S4 TII has the secondary rail threaded in with a 17mm banjo head bolt.

sucks you went through all that trouble on the wrong rail, the fitting will be different sizes(larger) threads on the TII rail.

 

I was thinking... I bought these off of a guy from here and could the secondary rail be from an N/A?

 

Damn, I figured that. Well, dang it. Got ripped off, but oh well. Least the primary fit ok. Thanks for the help.

 

np

should still press the guy to fix things on his side or be sure to leave feedback for him, it could be an honest mistake but he shouldn't be selling parts if he doesn't know what he has. the n/a primary will fit the same BUT the size of the bore in the rails is smaller so they won't flow as well as the proper TII rails will.

 

Yeah and it was my dumb mistake to not ask for pictures. Just assumed it would be all good. Never had a prob with a seller until now.

 

this same thing happened to me. i sold it as scrap metal. the rail that is.

 

No. I've used both intake manifolds. You CAN use the s4 fuel rail with s5 intake manifold set up. SINCE the primary fuel rail is bolted to the motor not intake... Just don't run the spacer.

The difference is in the inside diameter, of course s5 is bigger by a touch.

 

if you are using the s5 block with the s4 engine accessories, the only things you can interchange are the fuel injectors, front engine cover, oil metering pump, and throttle body.

the lower intake manifold has to stay s5 due to the extra intake port on the motor for the vdi.

 

we are talking turbo intake manifolds...

 

sorry. disreguard.