Hello, my name is Jon and I recently purchased an '87 TII from a board member. The car war purchased with a known bad engine and I am in the midst of removal right now. I ran into a few questions.

1 On the turbo is obviously a wastegate, but he exhaust manifold also has a diaphram actuator attached to it. When I look at the inside it appears that it shuts part of one of the runners to the turbine. I am assuming this is the strategy to decrease the lag...shut one runner off and increase velocity in the remaining runner to spool faster. I dont see this in the manual...was it factory on a different engine?

2. I am looking to increase the performance of this car, but nothing at all wild. I am considering the racing beat Rev II exhaust, fuel cut defencer and perhads a very mild street port. i would like to stay stock on the ECU and injectors but can replace if the flow requirements exceed the capacity. I will need to change the turbo as it appears to have a number of cracks in the web. Any good recommendations for a replacement turbo...nothing too big. And how are you adapting to the unsymetrical flange?


3. I may go all the way and rebuild the tranny as well. ik have done this on older cars. Does anyone make a nice rebuild kit and instructions like they do to toploaders and other transmissions?



Thanks and I welcome all input

JOn

 

1. Factory. It's called twin scroll and was present in all S4s.

2. With a REVII and an FCD you should be fine. Add a street port and it is going to take an ECU replacement with either a standalone or a modded stock ECU like the RTek. While this combination could be run on a stock ECU, that's how people blow engines. As for a turbo upgrade, the only turbos that fit on the stock manifold are the BNR hybrids which will require a standalone/Rtek to be reliable. If you go to a full aftermarket turbo you will need all the associated bits like manifold, wastegate, standalone (not an RTek), etc.

3. No idea. I had mine done at a local shop. Though I just disassembled one and it looks pretty easy when following the instructions in the FSM.

 

Thanks Aaron,

Based on this I think I will pursue retaining the stock turbo with the RB exhaust and FCD as first line mods. The remainder will be stock then.

Are there any good sources for new or reman RELIABLE injectors with stock performance? I have read too many things on this board about bad injectors that dont flow properly.

JOn

 

Have your existing injectors serviced by a local shop. Should be around $20 per injector.

If you keep the boost at around the fuel cut level, you should be fine for fuel. But if you start increasing boost, you will need to make mods. Generally the first step are larger secondary injectors and a piggyback (ie. S-AFC) to control them.

 

I agree if your going to go with a street port then you should increase the fuel. I use rc 720cc in jectors all the way around in my T2 with a walbro 255 high pressure fuel pump and an apexi power fc. I tried using an rtek at first but the stock ecu just couldn't handle what was going on.

 

Thanks for some great advice guys!

I will likely just go with the exhaust, FCD and port the wastegate to keep the boost at an acceptable leve with the stock turbo. I dont want to get in over my head to fast. I know a lot about older vehicles as I have some old mustangs in my collection.

YOur comments have me wondering a really fundamental question on this then...

If I go upgrading the injectors from the std 550 to say a 750, the ECM only knows the injector pulse length based on the AFM, IAT and some other parameters. If the the pulse does not change the system goes rich....but is compensated by the O2 sensor. Is it just that easy to stick in larger injectors and expect the system can compensate for this? Any ideas on how much excess capacity the AFM has in its range? If I increase airflow 10% will it still read correctly and is this in the stock ECU maps range? I have a lot to learn.

Thanks!!!

JOn

 

As I mentioned, if you need to upgrade the secondary injectors, you then need a piggyback to control them. Commonly an S-AFC is used which will allow you to turn down those injectors to keep the car from running rich.

The O2 sensor will not compensate for larger injectors.