Hi , im new to the board and i need some opinions on putting a Vdi manifold on a 86gxl , is it worth thr trouble ? Also i know that i will have to grind some "bumps" off , where are these and finally if i was to do this what parts would i need to take of the doner car? Any help would be greatly appreciated....Thanks

 

I've heard that it can be done, but it'll be alot of work. Basically, the intake systems from the 86-88 and 89-91 cars are very different.

By the way...how hard is it to remember your screen name?

 

Not too hard(thats what post-it's are for)

 

Hey Zach, whats with the egg? ^


Hey, i originally wanted to do this as well, but it didnt seem worth the trouble... especially when i found out that you had to take out our trusty mechanical omp and put in an elctric one... plus bend the connecting linkage, grind off bumps, add solenoids, move the egr valve... and the list goes on. If you're really serious and have the time, patience, and skill to do something like this, go for it... then let me know how it comes out Good luck to ya! I think it was rx7 ragtop that knew how to do this, might try searching for it, he just posted something on it a while ago..


~jesse

 

It takes a little work, but it is very doable. What you need is just the upper intake and plenum from an 89-91. Here is what you need to do:

1. When fitting the upper intake on to an '86 engine, there is a "bump" on the engine which causes the new intake to not seat correctly. This bump must be ground down.
2. The solenoid rack is in the way a little, you have to remove the EGR solenoid anyway, so you might be able to move around the solenoid that is in the way after you remove it (the EGR solenoid).
3. The EGR valve must be removed and a block off plate put in its place (available throug Racing Beat www.racingbeat.com )
4. The 86 throttle body should be used, but it doesnt fit correctly due to a nipple being in the way. Just grind off the nipple.
5. The oil metering pump rod must be bent some since the throttle body will be sitting higher.
6. The VDI action must be activated at about 5500 rpm. You need to get an RPM switch and use it with your old EGR solenoid to control the VDI control (vacuum operated).

This is a days worth of work, but it seems to me that it would be worth it. I havent tried this yet, but I plan to in the near future. There used to be a website with a good writeup on this, but it is no longer working. This is how I know what to do.

 

Thanks everyone , time isnt the prolbem for me because the engine is completly out of the car and i figured while it was out i should try to do it since i can also get the parts cheap,

MasteRX is there anything else i need ? Because i remember reading someware that i would need the fuel rails of of the doner car too .

 

This is not related to the swap, but I have had a 86 and a 90. The difference is fairly noticeable. I've once raced a 88 GXL with my 90 GXL. DEspite being 200lbs heavier, both car would pull out even. At 5K when the VDI kicks in, the 90 just pulls while the 88 slows down. It would be a nice thing for the 86-88 NA to have without adding the additonal weight of the 90

 

COOL!

 

Any one want to add to this? i just got my VDI in the mail and am going to "trail and error" this bad boy on there, any more usefull information would help in this process.. hehe. Thanks all.

88 GTU

 

I have a link to the website on my webpage. http://homepage.mac.com/carldavis/

The swap is pretty straight forward, but to do it easily, you need all the 89+ stuff. Basically, my RWHP and torque went from 138.2hp @7200 and 111.2lbs/ft @ 5300 to 151.7hp @ 7300 and 122.5lbs/ft @ about 4500, with a nice flat torque curve from 5000 to ~7000.



Carl

 

Well, crap. Nevermind. I just checked the link and it doesn't work. I will see if I can find a new link that works.

Carl

 

Thanks man, hey, do you have to replace the fuel rails and such?

Thanks man, Nice Dyno Sheet!

 

Well, let me elaborate on what MasterRX said.

True, this bump is located on the rear housing, top part of the clutch/flywheel view plate. It needs to be ground down to about 1/4 to 1/2 of the original height.

I found it easier to re-run the emissions lines using the 89+ emissions rack.

The EGR valve has to be removed. The manifold will not come close to fitting if it is in place.

There is a little nipple on the bottom side of the TB for the 86-88 that will hit on the VDI chamber for the manifold. This has to be ground down quite a bit. It is easiest to completely remove it by grinding it down.


I found it easiest to use a bike brake cable. I have it fed up from the bottom of the OMP through the black cable cover and up to the throttle body. There is an adjusting nut and bolt that allows for the cable to pass through the middle and the nut clamps down to tighten. I used this for ease of flexability over bending the rod.

I picked up a Summit Racing inhouse RPM activated switch and have it set to active a solenoid at 5200RPM. This proved the best point to open on the dyno. I had the pressure source T-ed into the little hose from the airpump to the air control valve, running through the emissions rack, up to the solenoid which is opened and closed by the RPM switch.

Thats about all I can think of right now, but if you run into problems, email me at cmdavis3@bellsouth.net

Carl