90+ manifold on a b21ft?

I searched and cant find good info.

Is the 90+ turbo manifold an easy(bolt-on)/desirable upgrade for a B21FT (84 245) or is it primarily an thing done with +t's and later b23 turbo motors?

im almost to stage 0 and trying to plan the next things to do.

It will bolt onto the head no problem.

<del>However, if you want to re-use your turbo (Garrett) you will need to have the manifold turbine flange machined smooth.

There is a step on the 90+ manifolds that is made to mate to the Mitsubishi turbos.</del>

The manifold allows for better exhaust flow b/c of the tubular style runners, but imo there are other areas to focus on for increasing power before swapping the exhaust manifold (3" dp / exhaust, turning up boost a bit).

Garret made Volvo specific turbos have the step.

OP, here's some more info.
http://people.physics.anu.edu.au/~amh110/8V_Folder/turbo_exhaust_manifold.htm

The Volvo Garrett T3 turbos from the B21FTs have a stepped flange too. Pictures below are log manifold and Garrett T3 from '83 B21FT (replacement version since it has water cooling too), reclocked Mitsubishi TD04HL 15G from some sort of 850, and an extremely cracked and abused 90+ manifold - click on thumbnails for full size.



If you swap to a 90+ manifold, you'll need to move your O2 sensor -- it originally goes in a hold on the bottom of the log manifold but the 90+ has no such provision. If you move the O2 sensor very far, you'll need to change to a 3-wire heated sensor (need to wire up power and ground). Finally, if you care, you'll need to fabricate a heat shield for pre-heated air to the airbox since the one from the log manifold doesn't fit the 90+.

Also notice in the pictures that the Garrett&log manifold opening is more rectangular vs. the Mitsu&90+ oval opening. You'll probably want to enlarge the 90+ opening for best T3 flow (although I've seen conflicting reports if this is typically needed).

Intro to 850 turbos and flanges is here: http://forums.turbobricks.com/showthread.php?t=10961

3" for the turbo is great and the way I will go on my red 84 242. A little smaller will be easier to deal with if going ove the axel. In my case the entire Exaust is rusty and falling off and the oil filter adaptor has a small leak and changing the motor mounts, just makes sense to me since I need more power.

Ursan said:

Garret made Volvo specific turbos have the step.

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That's true, except for one year: 1981 are flat with a gasket, SAAB had a real nice metal gasket on their version, as was typical on a lot of stuff like that they were much more innovative in those days than their volvo counterparts.

Preheat (unless you have smog visual) is basically a bad joke if it's intercooled and you don't live somewhere really really cold.
Non-IC and you need to drive in Siberia/Antarctica/Northwest Territories/Greenland, might as well have preheat too. Non IC and basically most of the radiator blocked would be good while you're at it. Otherwise, pre-heating air to then return it to ambient temp on a cold morning/light load at startup (when the pre-heat might actually be of any value) via the intercooler is a basically pointless exercise. If power output isn't of primary concern compared to predictable running in many varied conditions, non-IC can be logical. Many military/aircraft applications with turbos are non-IC (deliberately).

None of the feed/return lines will be in quite the right place. Downpipe moves slightly. But it does flow a lot better and if coated and well supported with some appropriate hardware seems to last. Originally, B21FT cars had a bracket that tied the turbo to the studs in the head as an additional precaution, since they were so concerned with hot hardware and it breaking/supporting all that heating/cooling vibrating heavy stuff.

Sadly, being volvo, they still didn't do a great job of it and until water cooled turbos and they tied the runners together (90+ manifold), the head hardware didn't last all that well as they warped at the head flange, but are less prone to cracking at the turbo flange on the pre-90 version unlike the 90+ which does crack. Definitely helps to open the 90+ up and smooth it out.

Clean lasting/longevity oriented adaptation is a few custom parts (feed, return, hardware at least), some difficulty sourcing a vaguely decent 90+, and a ton of time. Power output difference...if there's a turbine housing, manifold is opened up, exhaust, intercooler, and cylinder head to compliment it a bit. Never did the 90+ on its own, but under hood temps coated opened up 90+ and straight through exhaust, 3" outlet .63 exhaust housing is night and day compared to pre 90. Plenty of time though.

If it isn't opened up properly it's unlikely that there's a particularly significant gain.

90+ bolted right on my b21ft with stock turbo. 1981 California car if that makes a difference

BR1CKHOUS3 said:

90+ bolted right on my b21ft with stock turbo. 1981 California car if that makes a difference

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Did you see any power or other gains from it?

My current manifold has some small cracks and im trying to be smart about what i replace it with. If a 90+ is a relatively painless upgrade, (welding in an o2 bung included) even just for reliability than that seems like a smart way to go.


so to sum up and make sure i am on the same page...

-fits on engine with no mods
-need to add 02 sensor bung to downpipe
-?may need to be machined to accept stock turbo?
-?may need some mods to get oil lines to reach the turbo?

You can probably bend the oil feed line to work but the oil return will need to be changed. It it not necessary to machine the manifold flat as it will work fine without doing it.

There is a stud that comes out the bottom of the 90+ manifold. That is used to hold the support bracket. I made a support bracket that uses the stock B21FT catalytic converter bracket extended to go under the manifold to support it. Sorry I don't have a pic but it's just some small angle welded to the converter bracket. It extends to under the manifold and is held with the stud. That way I didn't have to drill the block and try to fit the stock 90+support.

I put a 90+ on but did it at the same time I replaced the head and installed the .48 cosworth housing. So I can't say it did much on it's own but the parts all work well together.

Step can stay. M8 hardware is not all that great for holding a heavier turbo on there.

Later (sometime in 1983) B21FT have the 90+ style bracket on them, early don't.

I made a brace that goes from that stud to a motor mount bolt, just drilled 2 pieces of 1"angle, I think the motor mount side needed a little shaping with the grinder and tacked a piece of 1/2" round stock in between them. Unbolted and welded solid. I'll get a pic after I eat and get back to head gasket replacement.

VB242 said:

I made a brace that goes from that stud to a motor mount bolt, just drilled 2 pieces of 1"angle, I think the motor mount side needed a little shaping with the grinder and tacked a piece of 1/2" round stock in between them. Unbolted and welded solid. I'll get a pic after I eat and get back to head gasket replacement.

Click to expand...

I did something similar, this is a 90+ setup on a 1982 B19A block. I did it from one piece though, 4 or 5mm thick flat steel:
DSC_0124 by P?ter Gede, on Flickr
DSC_0126 by P?ter Gede, on Flickr

Here's a pic of mine, the cooked end was on the manifold obviously.
[/url]2017-10-11_09-01-47 by John Skiba, on Flickr[/IMG]