SOHC V6 Supercharger

The purpose of this thread is to discuss the design and possible development and installation of a supercharger for my 2000 Sport SOHC V6 engine. I have no first hand experience with forced induction systems and want to learn from forum members that have them on their vehicles. While I don't plan to implement a turbocharger system, there are many problems common to all types of forced induction systems.

The easiest and least expensive solution would be to modify a Ranger SOHC V6 Banshee kit and purchase a used Thunderbird supercoupe positive displacement blower. However, the kit makes no provisions for an aftercooler which I think is beneficial even with only 5 psi of boost.

The Explorer Express supercharger kit includes a quality looking manifold but one is very difficult to obtain.

Once again, there are no provisions for an aftercooler.

I suspect the best solution for me would be a centrifugal supercharger with a water aftercooler. With my oil coolers and remote filters I have very little room in front of the radiator for an intercooler. I am interested in a boost in the range of 5 to 8 psi - enough for a significant performance increase but not so much to adversely impact reliability and require beefing up of engine internals or the transmission/torque converter.

Procharger sells a kit for the 2005 - 2010 Mustang V6.

But the Mustang configuration is opposit to the Explorer - intake on left and battery on right. Also, there is a lot more room between the engine front and the radiator rear on the Mustang than on the Explorer.


Vortech also makes a kit for the Mustang but there are the same problems.

The logical location for a centrifugal supercharger is the same side as the air filter box and intake manifold inlet port. Unfortunately, that is where the alternator is located. I'm investigating the possibility of replacing the belt driven power steering pump with an electric motor driven pump and then relocating the alternator to the old power steering pump location.

 

[2000StreetRod]

no retard improvement

I did a "hill climb" datalog this morning running 87 octane fuel with up to 10% ethanol. There was No retard improvement but a potential "tip" issue was detected. I'll perform another "hill climb" datalog running 93 octane fuel with up to 10% ethanol in a few days after searching for any possible vibration source that could be triggering the knock sensor. If the results are the same I'll upload the desensitized knock sensor retard tune and try another datalog.

 

[Dono]

Oh boy, that's not good. The maint on your truck has been the best I've ever heard of. I never did see where you had to replace those timing chain cassettes.
Its awesome your looking at this first. I'm really interested.
As much as that knock sensor's a pain in the a$$, it does let you know somethings going on.
The more I read on the sohc, the more I like it (other than timing chain design). Its a pretty progressive motor.

 

[2000StreetRod]

use to SOHC V6

Oh boy, that's not good. The maint on your truck has been the best I've ever heard of. I never did see where you had to replace those timing chain cassettes.
Its awesome your looking at this first. I'm really interested.
As much as that knock sensor's a pain in the a$$, it does let you know somethings going on.
The more I read on the sohc, the more I like it (other than timing chain design). Its a pretty progressive motor.

I have also grown to like the SOHC V6 in spite of the poorly designed rear cassette (I have two complete spare pairs). James provided me with three identical tunes except for knock sensor sensitivity. I normally drive with the stock sensitivity for engine protection. I have another with decreased sensitivity that simplifies tuning. The third has the knock sensor turned off for performance testing if I'm sure there actually is no detonation. Eight degrees of retarding the spark advance is a significant performance degradation. I really want to solve this problem before the blower install when there will be a real risk of detonation. On WOT testing for my current custom tune changing from 87 to 93 octane made no significant difference. There were runs at around 40 degrees F IAT with 8 degrees of knock retard. Then there were runs at above 60 degrees with almost no knock retard. That's why I concluded it was either a bad sensor or a vibration problem. I replaced the sensor with the Airtex unit identified for my vehicle and it didn't help. When I install the Banshee kit I'll install a new Ford OEM sensor.

 

[2000StreetRod]

M90 coupler & oil

Yesterday I ordered a new M90 coupler from DaRossi and two bottles of GM Performance supercharger oil from parts-powerhouse

The coupler is often a source of rattle (which my knock sensor might respond to) when worn and no special tools are needed to replace it.

 

[CDW6212R]

I also like the idea of the knock sensor, even though the 302 system doesn't use it.

For my 91 Lincoln OBDII wiring project, I will have the option to install a 4.6 PCM instead of the 302 computer. I hadn't planned to do that mainly because it would require wiring in and using COP parts, and the performance gain isn't that big of a deal. But there is a knock sensor in the 1999+ 4.6 systems, so that could be worth some more thought.

Dale, try to decide if the knock sensor is helpful for your application, given everything working as it should.

 

[snoranger]

I had hopes of using a Bosch idle air control valve (IACV) since I have one from past Volvos I've owned.

Unfortunately, after researching the Volvo wiring diagrams I have learned that the Bosch IACV contains a rotary valve that is controled by a variable duty cycle opening circuit from the Motronic control module and a variable duty cycle closing circuit. The Explorer IACV is a spring loaded plunger within a solenoid energized by a single variable duty cycle circuit from the PCM.

I guess I will have to fabricate something equivalent to the IACV mount on the upper intake manifold and similar to the throttle body spacer included in the Banshee Ranger kit.

The Banshee throttle body spacer is drilled to match the Ranger throttle body with a built in bypass port and the Ranger/Explorer IACV. My 75 mm throttle body has no bypass port and the bolt pattern differs from the Ranger throttle body. Also, I want to mount the throttle body in the 45 degree intake leg to have room for the throttle and cruise control linkage.

Dale, have you thought about using a late 90s/early '00s 4.6l IAC...

It uses a hose for inlet and the flange side for outlet. It may be easier to adapt.

 

[2000StreetRod]

inlet port IACV

Dale, have you thought about using a late 90s/early '00s 4.6l IAC. . . It uses a hose for inlet and the flange side for outlet. It may be easier to adapt.

Thanks Kevin! According to Rock Auto that one was used in the 2000 Mustang and Crown Victoria. From the photo the inlet port diameter looks comparable to the rigid tube diameter on my Sport. Ronald Caster had to increase the diameter of the bypass port in his throttle body spacer from 1/4" to 3/8" to get adequate idle control. Since I only need one port on the inlet side (pre-throttle plate) that would work fine. I could mount it on the electrical box and not have to fabricate the chamber divider. The entire chamber would be post-throttle plate giving me up to three ports: one for the main intake tube post-throttle plate, one for the fuel vapor management valve, one with a Tee for the PCV and the other for the combined vacuum reservoir bulb, heater water control valve, EGR vacuum regulator and fuel pressure damper. I like it!

 

[2000StreetRod]

pulley arrived

I now have a 2.7 inch diameter, steel, 8 rib M90 blower pulley

thanks to the generosity of Dono (who donated it to my project) and dropdtop (who packed and shipped it as his expense). Thanks so much guys!

 

[rpcaster]

I now have a 2.7 inch diameter, steel, 8 rib M90 blower pulley
View attachment 74273
thanks to the generosity of Dono (who donated it to my project) and dropdtop (who packed and shipped it as his expense). Thanks so much guys!

Check your max rpm for the M90, as I "believe a 2.8" is the smallest to use at a max engine rpm of 6,000"?
regards, Ron

 

[2000StreetRod]

M90 arrived

My supercharger arrived today due to the generosity of snoranger who sold me his spare 1991 Supercoupe M90 for a nominal sum.

It was shipped with the oil still in it and blower outlet down. It looks like the snout is leaking so I may replace the associated seal(s) when I encounter a project delay.

The rotors spin freely and quietly.

I did not see any nicks on the rotor blades.
Thanks Kevin!

 

[Dono]

That snout seal is really easy to replace. You can do it with the M90 on your truck very easily also.

Nice to see your almost there. Any updates on the knock sensor issue?
How about the air conditioning?
Fuel pump??

Oh man, one step at a time. It will all come together. I can't wait!

 

[2000StreetRod]

max blower speed

Check your max rpm for the M90, as I "believe a 2.8" is the smallest to use at a max engine rpm of 6,000"?
regards, Ron

That's a good point. My target boost is 8 psi or a pressure ratio of

(14.7+8)/14.7 = 1.54

According to one of the graphs posted by rocket 5979 the M90 efficiency at pressure ratio of 1.5 decreases from 58% at 10,000 rpm, to 52% at 12,000 rpm and to 48% at 13,500 rpm. I haven't measured my balancer's actual diameter but I think it's about 5.6 inches. My engine speed limit is still stock (6250 rpm).

5.6/2.7*6250 = 12,963

I've read that the M90 maxes out between 12K and 14K rpm with the earlier Supercoupe models maxing at higher rpms than the later ones which are more efficient. Hopefully my balancer is less than 6.1 inches:

6.1/2.7*6250 = 14,120

At 14,000 rpm and 8 psi the blower would consume about 50 hp. I'm speculating that my max boost will be lower than 8 psi with the 2.7 inch pulley because of my high flow intake and exhaust systems.

 

[2000StreetRod]

throttle body & linkage mount

I'll need some type of bracket to keep the throttle body from moving relative to the engine and the throttle/cruise linkage. There are two stud bolts marked with red arrows in the photo below.

If they have the same thread depth as the other bolts I'll move them to the locations marked in green. I'll purchase another stud bolt and install it at the green location identified below.

That way I can fabricate a two plane throttle body mount that would be much stronger than a single plane mount. Hopefully, the angle and spacing will be workable.

 

[jd4242]

That's a good point. My target boost is 8 psi or a pressure ratio of

(14.7+8)/14.7 = 1.54

According to one of the graphs posted by rocket 5979 the M90 efficiency at pressure ratio of 1.5 decreases from 58% at 10,000 rpm, to 52% at 12,000 rpm and to 48% at 13,500 rpm. I haven't measured my balancer's actual diameter but I think it's about 5.6 inches. My engine speed limit is still stock (6250 rpm).

5.6/2.7*6250 = 12,963

I've read that the M90 maxes out between 12K and 14K rpm with the earlier Supercoupe models maxing at higher rpms than the later ones which are more efficient. Hopefully my balancer is less than 6.1 inches:

6.1/2.7*6250 = 14,120

At 14,000 rpm and 8 psi the blower would consume about 50 hp. I'm speculating that my max boost will be lower than 8 psi with the 2.7 inch pulley because of my high flow intake and exhaust systems.

You "should have a 6" crank.I was searching for a larger one and measured a couple sohc..it might be a ford thing and I ""think"" having a IC changes the efficiency rate but the gm m90 has pulleys down to 2.3 and they have a 7" crank.I hit 9.9lbs @ 6, 100rpms with a 2.7

Pulley ratio 6.0" / 3.2" = 1.875 ratio

Theoretical boost = (charger size in liters x pulley ratio) / (engine L / 2) x 14.7 - 14.7

(1.5 x 1.875) / (4.0 / 2) x 14.7 - 14.7 = 5.97 lbs boost

Based on that you can estimate a rough gain of 90rwhp give or take. Of course how aggressive or how conservative the tune is, engine flow efficiency, camshaft specs, supercharger inlet flow efficiency, drivetrain losses, etc will play a sizeable role in determining your total number.

2.7" gives 9.8psi and 2.8" gives 8.9psi with stock crank pulley, M90, on 4.0.

 

[2000StreetRod]

You "should have a 6" crank.I was searching for a larger one and measured a couple sohc..it might be a ford thing and I ""think"" having a IC changes the efficiency rate but the gm m90 has pulleys down to 2.3 and they have a 7" crank.I hit 9.9lbs @ 6, 100rpms with a 2.7

I think the supercoupe has an intermediate pulley and I suspect the GM does also. That's why the boost is lower for a 7" balancer and a 2.7" blower pulley.

Thanks for providing the pulley size and the formula for theoretical boost:

Theoretical boost = (charger size in liters x pulley ratio) / (engine L / 2) x 14.7 - 14.7

2.7" gives 9.8psi and 2.8" gives 8.9psi with stock crank pulley, M90, on 4.0.

As I previously posted, 4pointslow with a 3" exhaust and a 2.7" pulley (or possibly a 2.8" - he's not sure) was getting 7 psi of boost. That's why I decided to try the 2.7". Hopefully, I'll be at 8 psi or under.

 

[2000StreetRod]

airflow range & rwhp

If I assume an engine speed range of 2700 to 6000 rpm and calculate the airflow:

CFM = (displacement*RPM/3456)*VE

Assuming volumetric efficiency at 2700 rpm = 95%:

(244*2700/3456)*.95 = 181 CFM

Assuming volumetric efficiency at 6000 rpm = 70%:

(244*6000/3456)*.70 = 296.5 CFM

With a 6" balancer and 2.7" pulley blower speed is:

6.0/2.7*2700 = 6000 rpm

6.0/2.7*6000 = 13333 rpm

If I assume a constant pressure ratio of 1.5 then efficiency varies from 62% to 48%.

From what I've read 1 psi of boost results in a 7% to 9% increase in horsepower. Assuming a current 180 rwhp, 8 psi boost and 7% increase per psi yields:

180*[(8*.07)+1] = 281 rwhp

I'm hoping with the higher speed pulley there will be some measurable rwtq increase below 2500 rpm where most light throttle driving occurs.

 

[jd4242]

I think the supercoupe has an intermediate pulley and I suspect the GM does also. That's why the boost is lower for a 7" balancer and a 2.7" blower pulley.

Thanks for providing the pulley size and the formula for theoretical boost:

Theoretical boost = (charger size in liters x pulley ratio) / (engine L / 2) x 14.7 - 14.7

2.7" gives 9.8psi and 2.8" gives 8.9psi with stock crank pulley, M90, on 4.0.

As I previously posted, 4pointslow with a 3" exhaust and a 2.7" pulley (or possibly a 2.8" - he's not sure) was getting 7 psi of boost. That's why I decided to try the 2.7". Hopefully, I'll be at 8 psi or under.

I would look else where for comparison numbers, some things seem to be a little off with his numbers
He also only put down 285rwhp with a m112 @15lbs off boost....do the math on that:shifty_ey:shifty_ey

 

[QueenCitySleeper]

Say your making 225 at the crank. My math by your calculations plus other factors = 230 rwhp

 

[Carguy3J]

I think the supercoupe has an intermediate pulley and I suspect the GM does also. That's why the boost is lower for a 7" balancer and a 2.7" blower pulley.

I have worked on both the Supercoupe and GM 3800 setup, in their "native" applications.

The Supercoupe M90 does, in fact use a jack shaft pulley arrangement to speed up the blower. The crank drives a "double" pulley, w/ the front, smaller "section" being driven off the crank. The rear, larger diameter section runs a second belt to the blower.

The GM 3800 setup does NOT do this. The blower is runs on a second, independent belt, from the rest of accessories, but the "double" pulley is the crank, and both sections are the same size. The belt for the blower is crank to blower, with a tensioner in between. Also, the GM blower does use a smaller blower pulley, w/ 2.1" being considered fairly "extreme", producing very high boost. Stock, is, I believe 2.7", with 2.6" - 2.5" being fairly common bolt-on upgrades. If I remember correctly, anything under 2.3" requires the OD of the snout to be machined down for clearance.

 

[Carguy3J]

"Funny" math

Say your making 225 at the crank. My math by your calculations plus other factors = 230 rwhp

Ummm, your calculations are WAY off......

First crank HP will always be HIGHER the RWHP, not lower. There is always a loss of power through the drivetrain, due to the frictional losses, etc... needed to drive the transmission, driveshaft, rear end,etc...

Also, depending on various factors affecting the efficiency of those components, the typical loss is anywhere from about 10%-20% (on the very high end- think HD truck). So, 225HP at the crank, would be between 180hp-202.5hp, at the wheels on a chassis dyno.