Brake booster in 3.5L

[Ed G]

Pondering next winter's project.....

Pardon my ignorance guys, but if I were to swap in a 735 engine, why wouldn't the same car's brake booster easily fit? The only recommendation I have seen is the 2002tii hydraulic booster. I'm guessing- Too many chassis mods? TIA

 

[x_atlas0]

It depends on which intake manifold you use. The stock L-Jet/D-Jet (aka the log style) manifold fits with the stock brake booster. The later, Motronic manifold does not fit with the stock booster, requiring a smaller one. The OEM part that does fit (without using a hydraulic system as used in the E28 ) is the 2002tii booster.

It is a bit of work to modify the L-Jet manifold to work with Motronic, as many of the parts to not line up and the wiring has to change. So, if you want to keep the custom work to a minimum, you can swap in a D-Jet system or go full Motronic and use a 2002tii booster.

Alternatively, if you are using stock carbs, there's no problem. I do recall that the triple 40 setup does interfere with the stock booster.

 

[Ed G]

I've got a complete CSI engine I don't mind scavaging. So you're saying- swap intakes to avoid interference? Do you know enough about megasquirt to say if I could benefit over Motronic 1.3 on the D-Jet hardware? Am I asking for more complications than it's worth?

 

[x_atlas0]

I've got a complete CSI engine I don't mind scavaging. So you're saying- swap intakes to avoid interference? Do you know enough about megasquirt to say if I could benefit over Motronic 1.3 on the D-Jet hardware? Am I asking for more complications than it's worth?

Do you mean "will MegaSquirt work better with Motronic 1.3 hardware compared to D-Jet hardware?" or are you running D-Jet/Motronic EFI right now? What is your proposed setup configuration in terms of block/intake/EFI system?

 

[Ed G]

I've got nothing but a stock CSI I can draw parts from. My goal is the best 3.5L bang for the buck. I do like the idea of incorporating the D-Jet logs though, and it would save the cost of the booster. Also- From previous posts, megasquirt sounds appealing.

 

[x_atlas0]

I've got nothing but a stock CSI I can draw parts from. My goal is the best 3.5L bang for the buck. I do like the idea of incorporating the D-Jet logs though, and it would save the cost of the booster. Also- From previous posts, megasquirt sounds appealing.

So you don't have the 735 engine you mentioned in your earlier post?

The best "bang for the buck" 3.5 job depends on how much "buck" and time you have.

The best-performing 3.5 is a M90 block with a B35 head, (ideally with custom pistons) a log manifold with 320i intake runners, running MegaSquirt or Motronic 1.3 with a WAR chip. That setup will provide ~200 rwhp, rev nicely, and run quite well in a variety of circumstances. However, as you noticed, it is a very specific set of parts from several cars and several eras. It takes time to get the whole thing together, and about 3k all in. You need some sort of tuning capability, so a MegaSquirt or modified Motronic system are required, unless you are going carbs.

The second-best running and the easiest 3.5 swap is a straight M30B35 and Motronic 1.3 swap, including the manifold. As previously mentioned, it does require the 2002tii booster, but everything else bolts right up. There is no customization required and virtually no special wiring. You can pick up a complete M30B35 with uncut harness and DME for under 1k easy, then the booster (last I looked) was ~250$ used. I went this route. If you have done it before, you can do it in a weekend since there is no custom fabrication. If you go this route, rather than MegaSquirt, I'd go for a WAR chip, which allows you to program the Motronic yourself exactly like MegaSquirt. You even get to switch to a MAF as part of the deal, which allows you to junk the horrible AFM.

 

[Sparky]

So X AtlasO, do you match the E12 intake manifold ports to the B35 intake ports?

It seems the ports are very close to the same height but the cylinder head ports are about 20% wider than the manifold ports. How far back up the E12 manifold would you carry the matching procedure? The manifold walls and the mounting flanges could get mighty thin on the sides so have you considered layering up some aluminum by welding for structural integrity along the thin areas where grinding will be done?

What fuel injectors should I be using? It seems 19# Mustang injectors have been mentioned but I don't have a part number. Will these be sufficient for the camshaft mentioned below?

I'm using a M30B35 engine with Motronic 1.3 FI and an E12 intake manifold with 320i runners and an existing Stahl 1 3/8" exhaust header. At some point I want to add a Shrick 284º cam and Mas Air Flow Sensor/WAR chip but I want to get the installation done and sorted out and see just what the actual condition of the engine is. Do you think these headers are too small and I would do better with IE 1 5/8" headers?

This is in a 71 2800cs with 3.0 brakes, LSD, and a 265 transmission.

Thanks for all your help.
Sparky

 

[x_atlas0]

So X AtlasO, do you match the E12 intake manifold ports to the B35 intake ports?

It seems the ports are very close to the same height but the cylinder head ports are about 20% wider than the manifold ports. How far back up the E12 manifold would you carry the matching procedure? The manifold walls and the mounting flanges could get mighty thin on the sides so have you considered layering up some aluminum by welding for structural integrity along the thin areas where grinding will be done?

What fuel injectors should I be using? It seems 19# Mustang injectors have been mentioned but I don't have a part number. Will these be sufficient for the camshaft mentioned below?

I'm using a M30B35 engine with Motronic 1.3 FI and an E12 intake manifold with 320i runners and an existing Stahl 1 3/8" exhaust header. At some point I want to add a Shrick 284º cam and Mas Air Flow Sensor/WAR chip but I want to get the installation done and sorted out and see just what the actual condition of the engine is. Do you think these headers are too small and I would do better with IE 1 5/8" headers?

This is in a 71 2800cs with 3.0 brakes, LSD, and a 265 transmission.

Thanks for all your help.
Sparky

Sparky-
If the ports on the head are wider than the ports on the manifold, then the gains from porting the manifold will be minimal, unless you increase the width all the way through the runner. Flaring it at the end of the runner won't help much, especially since the head is the wider point. The only loss this will induce is to create a small stagnant volume directly in front of the intake flange where the head is open. While it is certainly not optimal, I doubt it would have enough of an impact on performance to be a problem. Now, if the sizes were reversed and the head was the smaller port, you'd have a much bigger problem, as the intake boundary flow would run smack-dab into the head surface, significantly disrupting the intake flow.

The 19# Mustang injectors are considered an upgrade over the stock units by some. They flow slightly more than the stock M1.3 injectors and have a better spray pattern, according to supporters. The injectors were used on the modular Ford V8s for most of the 90s, so they are very cheap to find.

The Stahls should be fine. A bit of backpressure will help the exhaust valves seat properly. The cam should be a nice touch, but check to see if Miller has a stock 284 tune, it should save you some headache.