Just food for thought. On all my turbo cars, they ran better with the boost controller/wastegates and MAP sensor going directly to the manifold, individually. The devices/gauges connected together would be Gauges, BOV/BPV and any EGR/Emissions. I would Always only tap into the brake booster line for these.

 

Besides the brake booster line and PCV vacuum source, there are only 3 ports on the Cosworth. MAP for sure should be one. One goes to the vacuum distribution block. That leaves only one spare. I used it for AIT. For wastegates, BOV, etc I don't think it matters. If the pressure is slightly off, it doesn't matter since it's not quantitatively important. MAP and AIT are. My boost reference is off the compressor outlet though > solenoid > wastegate. According to Garrett, wastegate diaphragms are not supposed to see vacuum.

 

From the back of the Cosworth there are as I mentioned 3 ports.
1) going to Vacuum Block
2) Fuel Pressure Regulator
3) MAP Signal reference for ProEFI - Direct feed. (This goes into the battery box where my sensor is hidden from sight)

I can always move the hose for FPR from the actual manifold port to the vacuum block and pull the hose for Boost Controller/Wastegate from the block and put it to the manifold direct, but that is not solving the problem at hand.

 

Hey Gio, what EMS are you running? Just for comparison. I know Raj has Haltech.

 

I'm running the Haltech with the HKS AIT (wired directly to the Haltech) just like Raj

When I had the ProEfi I had the same problem as you and found out it was the vacuum hose that split where it plugs into the MAP sensor for the PROEFI
so it couldn't get a correct reading fouled my plugs

 

Just for reference my car went very rich 10's after the Cosworth install from the ssv, I had no leaks or map sensor changes. I attributed it to the different manifold and how they flowed.

 

Whew. Thanks for that Danny. I was beginning to doubt my install skills on such a simple task too. But I am still gonna go over everything Sunday (my next day off). Just in case.

OK, so that's 2 with Haltech that had no tuning adjustments after switching to Cosworth. And 1 in my same or similar situation. What EMS u running Danny?

OK, so now we are getting somewhere. Anyone else care to share their experience?

Again, this thread is in no way intended to knock the Cosworth plenum, just trying to find out what could be a potential cause or factor in resolving my problem.

 

Also Danny, did you re-tune shortly after the Cosworth install?

 

Your vacuum looks good, so its not a leak. Can you not tune it back to stoich? Is that the problem?

I'd also pull all your endcap bolts and loctite them. YOu dont need to remove the caps to do that. THey will back out otherwise.

 

not to mention the obvious, but was the car tuned with the 1200cc's? or did you install them with the cosworth??

 

Are you tuning by VE or injector pulse?

 

I am using the Fcon, to be honest my car has been down for the most part of a year it will be retuned soon tho.

 

Have you verified the MAP reading in your EMS logs/dashboard? Sounds like it's getting a bad reading.

 

I installed my Cosworth last fall (came from a stock + spacer setup). I used blue loctite on all the bolts and black gasket maker on the endcaps.

There is zero difference in my idle AFR and the only thing I had to do was add some fuel on the top end @ WOT. The Cosworth also dropped my wastegate spring pressure boost level from 14psi to 12psi because it flows much better than my stock + spacer setup.

I have an APS TT kit + UTEC.

 

I have to agree with most people. I have never seen an intake manifold swap change the tune up this much. Something else is going on here.

 

You are going to absolutely have to retune for any intake manifold change you make, particularly this one. Down low it should not need anything to at least start and drive the car, as the injectors are barely opened in the first place and IDC's are low. You will notice significant afr values from 5500 rpm on upwards though prior to retune

It sounds to me like you've got something else going on...even if the vacuum on your boost gauge says it's ok, I'd still check over everything. What that could be, is hard to say, but start with the simple stuff (vacuum lines, map sensor, gaskets/seals, etc etc etc)

 

^ with FI, the airflow change is minimal vs a crawford until above 6k rpms and even there, with an AFR in the 11s, there's plenty of room for error without a retune, well within the adjustable (automated/closed loop) trim range for the ProEFI.

It's the MAP reference going to the ProEFI that must be off. (The new hose is messed up Randy!)

 

a vacuum leak would make it run lean not rich so that is out of the question. the first thing that comes to mind if suddenly running rich is the air temp sensor. have you checked to see what the air temps are reading? If the sensor gets unplugged it will have infinite resistance and read extremely cold..

ross

 

Well there is no leak by boost gauge, and a small leak would not make a difference rich or lean at all since his fueling is driven by MAP. AIT corrections usually are not that dramatic, but it's easy to check... CAN gauge to the rescue!

 

I completely agree something else is causing his idle issues, a plenum change isn't going to make any difference, as airflow is next to nill and injectors are barely opened. MAP sensor is a really good, obvious first thing to consider

In the upper rpm, it very well be still driveable/safe - I suspect it will depend on several factors/other aspects of the car and the state of tune it has in the first place. But, a retune would def. be in order to maximize the benefit of the plenum.