NA to Turbo II conversion - Stage I (basic)

"Facts about the highly sought after turbo conversion, and what role I can play in supplying it"

Please read all information found on this page before calling or emailing
me with questions about a turbo conversion. I have worked hard to develop
this section of the site due to the high volume of requests I recieve
personally as well as see being asked on other tech forums. Please take
time to familiarize yourself with what you are getting into before asking
me about it. IF you ask me a question that I have covered already on this page, you will either be directed to come and read this page (if I am in a good mood) or ignored altogether (if I am busy). This is not to be rude, but just to avoid repeating myself over and over, as I get anywhere from 2-10 emails/calls per week asking about this stuff. If, after reading this page in it's entirety, you have questions feel free to contact me."

WHAT IS THE TURBO CONVERSION?

When people refer to a turbo conversion on a 2nd gen RX-7,
it could mean one of 3 things:

1) custom fitting a turbo and other required parts of the system onto the
nonturbo engine, keeping the drivetrain stock. This is the least expensive
(in most cases) method for turbo'ing your NA car, however it is also by far
the least desireable. Keep in mind most people's nonturbo is still on the
original engine, or at very least a high mileage replacement. Adding the
additional stress of boost, even if done properly, is asking too much from
a tired old engine. Not to mention that nonturbo engines are high
compression internally, and the intake is not set up for boost (6 port
variable intake). There is also much custom rigging involved in this setup,
and by the time you do everything that needs to be done you have a hacked
up engine bay and almost as much money as a true turbo conversion (see
below) could have cost you. The only way this setup is to last is to keep
boost way down, or rebuild the engine beforehand, either one is not much
fun. For some information and parts list on this type of swap, you can
check out the following thread posted by a fellow who did this and photo
documented the process. Please give all credit to the original author. This
writeup is not to be taken as "the only way" to do the swap, but gives you
a good idea of what would be expected to make it work.

http://www.rx7club.com/forum/showthread.php?s=&threadid=88540

2) Take all the stock engine parts out of a turbo II to put into your car,
just the engine itself and all the electronics that are required to operate
it in stock form, not the turbo drivetrain (for instance if you cannot find
one). This would retain your nonturbo drivetrain. This is not highly
recommended, but can be done successfully depending on the driver. To do
this you would need, at very minimum, an upgraded clutch and pressureplate
to avoid major slippage of the clutch under boost. You just bolt an NA
flywheel onto your new t2 engine and everything bolts together just like it
did. Below is a parts list that is the basic minimum for doing this type of
swap, along with basic instructions.

3)Take all the stock parts out of a turbo II to put into your car,
everything from front to back including the drivetrain. This is considered
the "proper" way to do the conversion, and will result in the longest
lasting choice. Below is a parts list along with basic instructions for
this swap.

SO WHAT DO I NEED TO BUY?
--Here is a helpful guide to what you need to look for.
**The following list is for the "engine only" swap as listed in #2 above.**

**Note that there is a BIG difference between the 87-88 turbo parts that fit 86-88 nonturbo cars, and the 89-91 turbo parts that fit 89-91 NA cars. IT is not adviseable to try and mix and match any of these parts. IF you have an 86-88 (s4) car, you need to obtain all 87-88 matching turbo II stock parts for use in the car. IF you have an 89-91 (s5) car, you need to obtain al the 89-91 matching parts for use in your car. Note also that 89-91 turbo parts are becoming EXTREMELY RARE AND EXPENSIVE. IT is much easier to find and afford all the 87-88 turbo parts in contrast to the 89-91 parts.**

• Complete turbo engine with intercooler
  
• Left-hand drive spec turbo wiring harness
  
• Turbo ECU (jspec ecu will work)
  
• *only for 87-88 turbo* knock control box, a small silver box up inside the
  passenger kick panel that plugs into the wiring harness. On 89 and later
  setups, the ecu handled this function.
  
• turbo boost sensor.
  
• Turbo throttle cable. 87-91 are interchangeable.
  
• Stock turbo fuel pump (87-91 turbo pumps are the same, but the bracket is
  not) or upgrade such as walbro 255. A rewire for full voltage from the
  fusebox is also recommended, as well as a re-ground in the hatch to bare
  metal, a new pickup screen and fuel filter.
  
• Stock turbo intake duct with blow off valve (if not present on engine
  already). The 87-88 TID is smaller than the 89-91, but either can be used
  in place of the other. Blow off valves are slightly changed but basically
  the same.
  
• Stock t2 precat/downpipe and midpipe (bolts to main cat) or
  aftermarket/custom equivalent.
  
• T2 hood with scoop (unless you go front mount intercooler from day 1)
  
• Turbo air flow meter (your old nonturbo afm will get you by if you cannot
  find one, however the turbo afm is said to be calibrated for slightly
  higher air flow on top end so it is something that might matter once you
  begin to push the car).
  
• Aftermarket boost gauge is recommended. Even though 89-91 owners can
  install the 89-91 turbo gauge cluster and the gauge will work, it is still
  not very helpful. 87-88 owners cannot install the stock turbo gauge cluster
  and expect it to work, the wiring harness differs in this area.
  
• Aftermarket upgraded clutch and pressureplate. Remember, you're buying
  this for a nonturbo, not a turbo, since you're using your old NA drivetrain
  still.
  

Keep in mind that you need to put the NA flywheel on the turbo engine.
86-88 NA flywheels mate to 87-88 turbo engines, and 89-91 NA flywheels mate
to 89-91 turbo engines. Do not mix and match flywheels between series (s4
and s5), they are weighted differently.

You also have to do a bit of rewiring for this to work in the 87-88 cars
(in teh 89-91's it is a basic plug and play).

You have to run 2 wires from the back of the alternator inside the cabin by
the ecu. Compare your old NA wiring harness and trace the wires that used
to be at the alternator back to the plug they ended at (one of the 2 large
orange ones inside the car). Now compare these pin positions with the
current harness. Cut whatever wires are presently there (theyre not doing
anything important) and splice in your 2 newly run wires. Be sure to cut
and insulate those old wires, so you're not backfeeding through some other
circuit. This keeps all your idiot lights from staying on all the
time (this is normally an indication of a failed alternator, and the car
thinks it has failed because the wiring was missing).

You also have to run 1 wire about 6 inches. On your old NA harness, find
the yellow/red temp sensor wire that went under the oil filter. Now find
it's pinout position on the orange plug that was inside the car. Compare
this to the turbo harness' plug. Now trace the same wire on the turbo
harness in the car. Cut that wire on the *engine side* of the turbo
harness, and jumper it over to the wire that is in the pin position the old
NA harness had the wire at. Be sure to cut this old wire and insulate it to
prevent backfeeding through that circuit. Now your dash temperature gauge
will work like stock.

OK, that's what is required to run the stock turbo II engine by itself.
**What if you want the whole drivetrain as well (as listed in #3 above)?
Here is the additional list for those parts:**

• Turbo flywheel appropriate to the year/series engine (86-88 or 89-91)
  
• Turbo clutch kit
  
• Turbo tranny
  
• Turbo starter
  
• Turbo driveshaft
  
• Turbo rearend
  
• Turbo halfshafts

You CANNOT mix and match any of these parts with nonturbo parts. Everything
is different. You either change ALL the parts listed above, or none of
them. Note that other than the flywheel, the drivetrain parts really arent
specific to any year. Basically the only small changes made to these parts
from 87-91 do not matter to performance. In otherwords, it doesnt matter if
you buy an 87 transmission and a 91 rearend, it'll still work just fine.

OK, SO I KNOW WHAT TO BUY. WHERE CAN I FIND IT? CAN YOU SELL IT TO ME? CAN YOU INSTALL IT?
There is usually no one source for all the parts unless you find an entire
partscar, which is the best route if you can find it. Buying one piece
here, one piece there, all from different sources is not the most
desireable way. You can look at the online forums such as
rx7club.com/forum, teamfc3s.org/forum, nopistons.com, ebay,
thepartstrader.com, etc. to find all these parts individually or as a package.

Alternately, **ON RARE OCCASIONS** I might offer a complete turbo
conversion package. The ones that I get are 87-88 cars. Basically what
happens is I find a complete t2 in need of an engine, or wrecked, and I
part it out. I gather up all the required parts and sell them together.
Usually I rebuild the engine before selling the package. On the rare
occasion that I have such a package for sale, it usually goes for around
$2500-3000 rebuilt (usually to customer spec), plus installation or
shipping. Installation of turbo conversions (you bring the parts yourself)
usually runs $1000. Installation of a package I sell is usually discounted
to around $3500 installed, along with trade for your old NA
drivetrain/engine/electronics, but this price depends on each situation.
Shipping a complete t2 conversion usually costs $225-450 depending on your
location. No core charge/core is required for the conversion package, but credit will be given for any cores that are traded in, be it N/A or Turbo.

**NOTE that I do not get ANY 89-91 turbo partscars or parts.** Those of you
with 89-91's wishing to do this conversion are going down a hard road. I
suggest that you buy a jspec engine, rebuild it, and use an aftermarket EMS
such as haltech or microtech to control it, bypassing all the necessary
stock electronics and the expense and hassle associated with trying to find
them. Your final price will end up roughly the same as the 87-88 conversion
mentioned above, but your end result will be obtained faster, and be a
better setup as well.

DO YOU HAVE ANY TURBO CONVERSION PACKAGES AVAILABLE NOW? IF NOT, WHEN WILL YOU HAVE?
Rest assured that if I have a package available, it will be posted
conspicuously on this page as well as other sites. After all, I'm not here
to hide parts in secret, Im here to sell them. IF you dont see anything
posted about me having one available, it means I dont have one.
When will I get another? I have no idea, honestly. I might go 6 months
without buying a single partscar, and then buy 3 in 1 week. I never know
when Im going to see one and buy it, or someone might call me up and offer
to sell one. Unless you know a good psychic, I have no answer to this question.