A 3.4 DOHC Build then... F40 Turbo (Page 3/57)
Fierobsessed FEB 07, 12:06 AM
Thanks!
The shifter cables would have interfered with the intercooler I'm pretty sure. As it is they go right through the 180.
ericjon262 FEB 07, 12:13 AM
I'm liking your build so far! Turbo 60* FTW!

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I know these lines Look crooked on paper, but I swear I've got them straight in my head.

http://www.fiero.nl/forum/Forum2/HTML/119122.html

fieroguru FEB 07, 06:40 AM

quote
Originally posted by Fierobsessed:

Thanks!
The shifter cables would have interfered with the intercooler I'm pretty sure. As it is they go right through the 180.



You might try mounting the intercooler along the frame rail on the front side of the transmission with the inlet/outlet pointing up.


I have slightly more room there due to my engine/transmission placement being further to the rear (needed for idler/firewall clearance on the LS4), but there is still quite a bit of space there and it would be further away from some heat sources.


If you get creative, you could probably mount it in front of the wheel well on the driver side and route the charge pipes through the fuel fill opening in the side panel.
fieroguru FEB 07, 02:02 PM
Another option if you want to do some more fabrication... shorten the intake runners on the upper intake and then take the intercooler and cut off the outlet housing/taper. Add a 2"- 4" open plenum between the intercooler core and the start of the intake manifold runners and then weld it all up. The throttle body would need to be on the inlet of the intercooler, but the volume between it and the ports would be very close to stock.

Here is a shortened intake, just needs the intercooler housing welded off the backside of it (covering the valve covers):
Fierobsessed FEB 07, 04:21 PM
That thought did cross my mind, about an intergrated upper intake manifold/intercooler. I have a 96-97 intake that I could have modified to do that with. Maybe I'll still make something to that effect later on.

Either way, I started welding up my charge pipes last week. And heres the result:
Post intercooler pipe welded


Pre intercooler pipe welded


The Blow Off Valve added


Honestly, I was a bit out of practice with aluminum, towards the end they started looking like I knew what I was doing


As far as I'm concerned, the Intercooler is done. My only remaining tasks with it are to mount it properly, and build what I need to insulate it from the radiant heat of the exhaust. Header wrap, foil lined glass heat tape, and some metal shielding will be my weapons of choice. I've had really good luck with these in the past.

One thing I really like about the AWIC's is that you can cool the core by running the pump and a fan on the front mount. So a little heat from the exhaust isn't going to bother me much.

Next on the list, Transmission mounts!

Previously, I was using Rodney Dickman poly transmission mounts, and his brackets with my old Getrag 282. I am also using his poly engine mount as well. I'm keeping my original dogbone setup, and Rodneys engine mount. For the transmission, The rear mount is going to keep his poly setup, with a custom bracket between the transmission and the mount. This is what I came up with:






I made it out of 1/8" steel, it took 6 pieces to make it. It's actually pretty light and very strong. I'm not to worried about this piece!

Then For the front mount, I found that Rodney's mount wasn't compatible with the transmission, there was some interference between the mount and the bosses on the front of the transmission. There was a pretty simple solution to this problem. I removed the polyeurathane mount from the bracket and bolted it straight to the cradle using the factory holes. It's on a little bit of a diagonal, but who cares. Next I fabbed another bracket. For as simple as it looks, its actually as complicated then the rear bracket was, and used 6 pieces of steel as well. Mostly because the bosses on the transmission weren't faced off on the same plane.




One thing I had a problem with in the past, is cracked cradles. The front mount has a tendancy to tear the cradle at the bolt holes. I modified the cradle when I first did the 3.4 DOHC swap to remedy this issue. This is what I did then:

That should be plenty sufficient still.

There is an interference between the cradle and the F40 transmission where I needed it to be located. The factory position for the engine to the best of my knowlege places the centerline of the crankshaft 9" above th bottom of the cradle, and 19" from centerline to the rear cradle mounting holes. The interference was located here:

This is looking from the drivers side wheel well at the front transmission mount.

With the rear mount in place the transmission was resting in the front on this interference, which is actually about 1/8" above the intended location of the engine and transmission. So some minor clearancing will be needed. I could cut the part off of the transmission, but instead, I will modify the cradle.

And with the transmission mounts done, it is time for yet another test fit.

Ok, so this picture makes me a bit giggly.

Bit closer then I intended it to be, but still perfectly fine.


Clears the cradle by 3/8" or so


Clears the frame rail by 1/4" or so



At this point. We are at where this project is at present day. So I'm going to head back to the garage and remove the cradle yet again.

I'm currenly waiting on the various 90's of pipe and other stuff to build the turbo crossover from. I have nothing else to do till those show up.



Silicoan86 FEB 07, 10:55 PM
Fantastic build! I'm really enjoying reading this thread.

I'm surprised that you are still using the 91-95 style intake manifold though, the newer style really flows a lot better. Was it a space concern? Of course, as fieroguru mentioned, you would probably benefit greatly from a custom short runner manifold with this build.

[This message has been edited by Silicoan86 (edited 02-07-2013).]

Joseph Upson FEB 08, 05:44 AM
From experience, clamp your vacuum tube fittings that are subject to boost pressure, the tube to my wastegate came off a couple times but fortunately I didn't over boost the motor. Consider your vent tube size from the valve covers, they were not optimized for boost and can be improved on. If you intend to run double digit boost numbers crank case pressure can build faster than it can be relieved through the stock PCV tubes and at some point lead to seal leaks (a very common character with boosted motors) not to mention possibly force oil into the turbine housing. It will also cause the oil to get dirty quicker.

Not sure what your plans are for oil cooling but one of the best options out there is the sandwich oil cooler found on some VW motors and more appropriately the one I have that comes on some of the 3900 motors. It uses a nipple fitting in place of the block drain plug for coolant flow and a return "T" into a heater hose. I didn't realize it initially but engine oil comes off of the bearings hotter than coolant and at operating temps IS hotter than coolant so you can regulate it with your engine temps and keep it cool and near its most effective viscous range instead of wide temp swings associated with an external cooler. I don't have mine installed yet and my oil temp gauge shows highs of around 240 deg after running the car a little hard with 185 deg coolant temps.

That's a very nice looking turbo so whatever you can do to avoid ever having to take it down to work on it is worth it.

I use the same interlocking GM poly mounts picked up from AZ and at the moment do not use a torque strut so they hold pretty dogone good although a torque strut should be installed for better stability. I didn't reinforce the front cradle mount but had to reinforce the rear cradle mount pad area because it sees the most stress under load and mine actually cracked.

[This message has been edited by Joseph Upson (edited 02-08-2013).]

Fierobsessed FEB 08, 05:50 AM
I have a complete 96-97 Intake manifold set. But for a bunch of reasons I decided against swapping it over.

My main reason is that I really don't care about what my peak HP is, I want a very broad range of high torque levels, something that resembles a superchargers behavior. We can all agree that the more low end torque an engine can produce naturally aspirated, the faster it will spool a turbo. Short runner intakes, or fatter runner intakes have a distinct disadvantage in this field, but make up for it with a more peaky powerband. I want this thing to spool up extremely quick. I probably went one size higher then I needed on the turbo though. That's why I chose to keep the 91-95 intake.

The other reason was that It is far less work to leave it as is.

Not sure when my Xover tubing will show up, so I'm going to look into other things to work on in the mean time.

A little glimpse into what I'm doing with engine management.
I plan on wiring this engine as a Turbo Grand Prix Using a 1227730 ECM. I have somewhat lofty goals for the programming, but after some of the software I have written for these and other ECMs and had working beautifully, I've built up a lot of confidence in my ability to program. Unfortunately, moreso then my ability to actually tune one.

I will be running 3 IAT's, 1 for Ambient temperature, 1 pre intercooler, 1 post intercooler.
I will also have the ECM controlling the intercooler pump and as well as its native cooling fan control. Have the two work together.
Because of the multiple IAT's, I will be able to log the performance of the intercooler.
I also have a Wide band setup, which will also be running to the ECM for logging purposes.
The ECM needs to be tuned and programmed for:
Manual transmission
Siemens Deka 60lbh injectors
Boost control beyond a few PSI
Modified output (ALDL) Logging
Intercooler control
Expanded input usage for the IAT's
3.4 DOHC flow characteristics

Not sure If I missed anything.
Fierobsessed FEB 08, 06:06 AM

quote
Originally posted by Joseph Upson:

From experience, clamp your vacuum tube fittings that are subject to boost pressure...

If you intend to run double digit boost numbers crank case pressure can build faster....

Not sure what your plans are for oil cooling...

rear cradle mount pad area... cracked.




All very good points. I have planned to make my vacuum tubing of stainless, its prettier, and tougher. And I absolutely plan on clamping every connection. There is no excuse for hoses popping off!

I haven't really looked into what it will take to vent this motor correctly, but for sure I will have to do something about this.

I haven't addressed oil cooling yet, but I do have an external oil filter kit I might use. Some of the older 3.4 DOHC's came with a built in oil cooler that the filter mounted to. Apparently some other models have it too if you can find it. I'll have to remember to look for this the next time im in the U-Pull-It.

I agree, the rear pad should see a lot of engine stress! it is closest to the axle of all the mounts, so it see's the greatest forces. I've even crushed the rear mount on a getrag once from one hard launch. I should do something to reinforce it before I finish this project.

Thanks for the suggestions and the compliment!
Will FEB 08, 12:59 PM

quote
Originally posted by Joseph Upson:

Not sure what your plans are for oil cooling but one of the best options out there is the sandwich oil cooler



Many TDC's had a sandwhich cooler installed from the factory on the oil filter boss.

Edit:
quote
Originally posted by Fierobsessed:

Some of the older 3.4 DOHC's came with a built in oil cooler that the filter mounted to.



Ditto

[This message has been edited by Will (edited 02-08-2013).]