My 2V turbo experiment

If you know me, you know I love forced induction, especially turbochargers. I built a 660hp 3.2 Mondial, a 600hp 348, and an 800hp 308. But not everyone wants a suicide machine.

In the stable I also have a 1982 Ferrari Mondial 8. It's the exact same drivetrain as the 1980-1982 308GTSi/GTBi. I'm posting this hear because the 308's outnumber the Mondial 8's something like 10:1.

Almost two years ago I bought a Mondial 8 on ebay. It needed a fuel pump and a few other things and ran like absolute crap. Eventually I found one of the crank trigger sensors had been cut and the polarity swapped, this seriously retarded the timing on one of the banks (the front if I recall correctly). Once fixed we managed to make 156whp on my Dynojet 248 dynamometer. Even with the typical 19% drivetrain loss this is below the 205 horsepower that Ferrari quoted. 156whp/.81 = 192 flywheel horsepower. About thirteen down what Ferrari quoted. Everyone says the 2V injector motors definitely made less power than the carb'd cars that were rated at the same 205 flywheel horsepower, so I think my 156whp is a good representation of what these cars originally made.

Just over one years ago we whipped up what we hoped would become a simple Stage 1 turbo kit. We used a GT35R turbocharger, made a Y pipe to route exhaust to it, mounted it under the trunk, fed it out from a fitting we added on the oil filter mount, and used an electric scavenge pump to move the oil back up to the motor (teed into the ? shaped hose on the side of the rear cylinder head). We plumbed the intake piping to blow through the CIS injection. This is what several 1980's turbo companies did (Prancing Horse for example). I attached my original doodle that was my plan. I had hoped to draw through the CIS, but because of plumbing issues we ended up with blow through...a decision that came back to haunt me.

Note - don't buy the black exhaust/header wrap. It ages quickly to white.

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Dyno testing and street driving went poorly.

First, there actually was enough fuel to support about 240whp, BUT the Bosch CIS fuel mixture was originally designed to provide normally aspirated air fuel ratios. That's quite a bit leaner than safe turbo air fuel ratios.

Second, the DigiPlex ignition curve was too advanced. In the real world I could hear detonation on the second pull. (first pull was cool enough to barely avoid the detonation).

I ran out of available time and the Mondial got shoved into a back spot in my shop. Waiting patiently.

 

So during some downtime for quarantine and other things I designed and installed this crank trigger ignition system: http://www.atsracing.net/Parts/Details/FerrariIgnition

It's similar to the Electromotive system but uses a complete stand alone ecu so I can add fuel control later if I want to. Plus lots of other goodies like knock detection, boost control, intake air temp, data logging, etc.

I used an OEM Porsche CIS rubber coupler to go from a 3" boost pipe to the huge 5" CIS inlet (and do a 180 at the same time).
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Now we had a programmable ignition system that would allow me to dial back the advance to something more appropriate for a turbo application. The rule of thumb is 1 degree of retard for ever psi of boost, that worked well for the high rpm, but the midrange required about twice that.

I forgot to mention that the clutch started slipping around this time. It was original and pretty worn. I already had one on the shelf from some experiments with my 308. So I took a weekend to install that.

Back to the dyno. Final results for the day were pretty good. 249 or so wheel horse power at 7psi of boost. That is 307bhp.

I saved the tuning file but forgot to "make changes permanent" in the ecu. Opps. Rookie mistake. Car drove fine, just that I wasn't able to reap the rewards of my tuning (was closer to 220whp) as I drove home.


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Tuning was going well. But I knew I was out of fuel with the CIS system and the air fuel ratios in the graph above a leaner than I wanted. So I wired in an additional injector to the ecu and installed in the intake pipe. I also wired an electronic boost control solenoid to the ECU.

The injector would actually solve two problems. First I could add as much fuel as I needed, second it would help cool off the intake air charge, sort of like running through a sprinkler on a hot day. This actually turned out really good and I never measured an intake air temperature over 120 degrees F at the intake manifold.

Back on the dyno I found that I could not get enough fuel to the new injector from the CIS meter. I had originally plumbed it with a double banjo bolt off the WUR feed line, then I tried moving it to the cold start injector with a double banjo, then a single banjo (eliminating the cold start injector in the process). So I ended up changing the entire feed line from the filter to the CIS meter. I used -6AN hose and installed a T that goes to the additional injector. Now we finally had enough fuel to use that electronic boost control solenoid.
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Well the Porsche CIS coupler is too weak and inflates under boost! (I’ll put a video in the comments). Eventually it distorts enough to leak or even pop off. That’s why the massive dip is at 7000rpm.

But on the bright side we crossed 300whp. We’re making almost double the original horsepower. The strange dip at the end of the pull is a boost correction that I messed up, but I did not get a chance to fix because the coupler kept coming off.

But focusing on the bright side, we had almost doubled the original factory horsepower and were at 371bhp. Not bad for the slowest Ferrari ever.
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I think you provided proof of why a bolt on turbo or superchargers on these engines without a ECM is a bad idea. Now how long will stock pistons and rings hold up?

 

Amazing adventure,,please keep us updated

 

Videos from the first dyno session. It still has a Ferrari like sound. I'm using a F-body muffler that has one 3" in and dual 2.5 out on opposite sides.

 

At 13 psi I was finding it basically impossible to keep the Porsche coupler in place. It kept blowing off near the end of the dyno pull. There is no bead on the air flow meter to hold a hose securely, and I would have to pull it off to weld one one. So I came up with a quick solution. We made a short piece of 5" tube, added some bead material with the tig welder, and a crossbar that bolts to the CIS meter. Basically a bolt on bead.

This worked pretty well and I thought things were going good.......
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Until I realized this was happening:



The rubber coupler was blowing up like a balloon!

 

I decided to try and rig a quick fix. I got some 200lb tensile strength zip ties and externally reinforced the coupler, plus I wrapped two around the CIS meter to help hold it together. This worked fantastic and I finished tuning the car to 300whp at just 12psi. I wanted to run more boost, but the backpressure was pushing open my wastegate and no adjustment to the boost duty cycle map could prevent this. When we started this project I didn't know it would handle this much boost so easily so I only put a 4psi spring in the wastegate. I swapped that out for an 8psi spring. Now I had to completely recalibrate the boost controller duty cycle.
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I will always regret that I was not filming what happened next. It was spectacular!! During a dyno pull the Porsche coupler burst at the CIS meter. The shrapnel from the zip ties hit and exploded the fluorescent light above the dyno, sending glass everywhere. AND there was also massive engine backfire that blew the pipe off the throttle body, ripped through a fuel line to the WUR and TACO'd the CIS metering plate!

Everything (except the now shredded coupler) went back together OK. My rudimentary body shop/metal working skills flattened out the CIS metering plate and I stole the fuel line off the cold start injector to replace the broken one on the WUR, and then I just plugged the cold start port. Reassembled the CIS meter and we were back in business. But I think the fuel pump switch inside the meter got damaged because my fuel pump is now on whenever the key is on.

Oh, we did hit 306whp and look to be on track for 320whp. The engine is doing just fine, we are somewhere over 70 turbocharged dyno pulls so far (plus 42 normally aspirated pulls).

My next step is to make a CIS "hat" out of aluminum that will hold 20psi of boost. Everything else in the system is working flawlessly so far. But that may be a little while because I need the dyno back to tune some customer cars and I just felt the clutch slip in my 600hp 348 so that has to happen soon too.

 

So in summary I can say that the 2V motor is not as weak as I had heard. This Mondial 8 engine is 100% stock, stock pistons, stock head gaskets, stock valves. By doing the turbo kit RIGHT with modern ignition, fuel and boost controls we have been able to (almost) double the original horsepower without any consequences.

Aaron

 

Did you run a leak down test before and after?

 

Why are you only testing first gear? (Not a criticism, i'm curious to the methods)

 

That is third gear. The gear I use on the dyno is chosen based on vehicle weight and expected power. My dyno is an inertia dyno, it reads (almost) the same power regardless of what gear you are in. So the choice is really about getting enough resolution in the data.

 

Ah. I thought it was first. Seemed odd. Thanks for the clarification.

 

It’s rips through third gear pretty quickly now, haha.

 

Does your typical turbo install require deleting another accessory? (IE, the a/c compressor)

 

Nope.

my smog pump is gone, but that was done by the previous owner(s).

 

This is the new boost hat for the CIS flow meter. It's not 100% done in these photos, there are two nuts with sealing washers on top now that attach to 6mm studs that hold it down (plus a clamped coupler).
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Looking very neat now. Curious to hear how the pistons and pin bushes hold up over time. Have you settled on 12psi?

 

Ferrari made a 2.0 turbo around the same time. It has lower compression (7:1) but ran almost 9psi of boost with no electronic controls to limit knock or reduce timing or boost under high temperatures. A few years later they added a (crappy) intercooler, and a knock sensor and upped it to 1 bar of boost. I feel like with modern controls and a modern turbo that doesn't have much back pressure I'm very safe.

Aaron