non stock exhausts

minty73 · Post by **minty73** » Thu Jun 03, 2004 2:01 pm

would fitting a non stock exhasust, empi, bugpack etc, have any pros or cons to my 1.7 FI engine?

can anyone recommend any?

DeathBus · Post by **DeathBus** » Thu Jun 03, 2004 2:22 pm

Bugpack.... When I put mine on I didnt notice any performance difference, maybe 2 or 3 more horses, but nothing to write home about.

raygreenwood · Post by **raygreenwood** » Thu Jun 03, 2004 4:41 pm

You can get a little better throttle response, but many times..depending on the state of tune, you can run worse. If it actually lowers back pressure and you scavenge better, the ECU has no way of knowing that...and you can run a little lean. If so, its a quick tweek of the MPS. Ray

minty73 · Post by **minty73** » Thu Jun 03, 2004 11:42 pm

a tweek of what ray? sorry new to all this FI stuff

raygreenwood · Post by **raygreenwood** » Fri Jun 04, 2004 10:25 am

Manifold pressure sensor. I would get into the FI a bit and learn it...before you start swapping to non-stock parts. There is much to be gained through adjustment. Ray

DeathBus · Post by **DeathBus** » Sat Jun 05, 2004 6:35 am

I never realized they had a manifold pressure sensor. Hmmm might have to check that myself, when you have to much backpressure what does the ECU try to do?

raygreenwood · Post by **raygreenwood** » Sat Jun 05, 2004 7:15 am

Deathbus...you have a 73 412? Does it still have D-jet injection? If so, the fist sized silver contraption on the left hand side of the engine compartment with the single vacuum line and the 4 wire plug is the manifold pressure sensor. They call it the pressure sensor. It measures vacuum and is the load sensor for the FI. It sets your fuel mixture.

Any improvments to running that are done downstream...ie: exhaust flow, are invisible to the ECU...if they do not affect the vaccume that the MPS uses to set the fuel mixture with. When exhaust flow increases, it scavenges gases out of the cylinders faster. That, because of the exhaust/intake valve overlap used on most of the D-jet, can pull some of the intake gases into the xhaust. It can increase emmissions readings, cause the exhaust to run hot (due to fuel combusting in the muffler)....and not be seen in the vacuum signature because the intake valve closes quickly. So you are losing intake charge...running lean and the ECU and MPS will not know it to correct for you. Ray

DeathBus · Post by **DeathBus** » Sat Jun 05, 2004 8:02 am

raygreenwood wrote:Deathbus...you have a 73 412? Does it still have D-jet injection?

Hell yes it's still D Jet, and I am going to keep it NO MATTER WHAT

Carburetors on it, YUCK! TRAVESTY.............

I'll check it out, although I am very suspicious of this engine. The original engine was replaced with a Bus 1.8. the freaking dipstick is way down beneath the air intake, makes it a severe BITCH to check the oil. I have already had to replace 2 injector connectors. The guy who swapped the engines was a "914 mechanic" as the PO told me. But as it looks he was more of a hack than a true mechanic. So who really knows if all the components are even there. This is really the first time I will be digging this deep into the FI. The car has ALWAYS run awesome. When this engine pukes I am thinking of going up to a 2 L, going to try and use the D Jet.

raygreenwood · Post by **raygreenwood** » Sat Jun 05, 2004 9:07 am

The sad part about the bus 1.8, is that it put out less HP than the 1.7 with D-jet. But, they are good engines. The D-jet will do a 2.0 no problem, but I would look around for the 914 diameter runners, and either the 2.0 bus...but prefarably the 2.0 914 plenum. Ray

DeathBus · Post by **DeathBus** » Tue Jun 08, 2004 4:12 pm

After doing much more digging, I find the case is not stamped with an AW but a W. BUT the case has a hole for the bus type oil filler, but no cut out underneath for a mech fuel pump. Does this mean I have an engine from a Wagon?

raygreenwood · Post by **raygreenwood** » Tue Jun 08, 2004 7:07 pm

Yup....if the cast in hole is machined through and not just a casting boss...and its a W case, it is/was a 1.7L for a wagon. Ray