SOHC V6 Supercharger

[jd4242]

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.

For gm 3.8 is stock and belive the crank is 7" and produces around 8lbs.anything under 2.7 the snout has to be milled and that's when they start to consider it extreme. I've seen a 3800 with a 2.3 or 2.1 can't remember but it was they smallest pulley available with a 7" crank.said it was also the max safe limit the blower could spin, think it was producing around 23ish pounds of boost.it was removed for a smaller pulley and NOS was added instead.

 

[Carguy3J]

For gm 3.8 is stock and belive the crank is 7" and produces around 8lbs.anything under 2.7 the snout has to be milled and that's when they start to consider it extreme. I've seen a 3800 with a 2.3 or 2.1 can't remember but it was they smallest pulley available with a 7" crank.said it was also the max safe limit the blower could spin, think it was producing around 23ish pounds of boost.it was removed for a smaller pulley and NOS was added instead.

Oops. Yeah, you're right. I mis-remembered.....

 

[QueenCitySleeper]

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.

Easy now, lets not get our drawers in a wad My apologies, I should have specified. The 225 is my estimate of his current crank HP. The 230 RWHP is my estimate after the supercharger install on his current desired boost.

 

[2000StreetRod]

Update

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

I picture that being a messy process.

Any updates on the knock sensor issue?

I sent a PM to Jakee who had the same problem. His response: "The timing was being pulled as soon as the truck went into open loop, no matter what I did.

I replaced the knock sensor but it was still pulling timing. I went into the knock sensor retard table and reduced the 8 degree timing value to 2, 1, and zero, meaning I pretty much deactivated the retard function. I didn't do this until the MAF function was spot on and the fuel trims were set to 11.3 to 11.7.
I have beat on my truck for a few years now and never had a problem. Every once in awhile you can pull the plugs to see if you see any signs, I myself have not seen any indication of knock."

James Henson told me not to worry about it and that he would take care of it in my tune after the blower is all installed. I haven't had a chance yet to do another pull running premium fuel. I want to add a pid that tells me exactly when the PCM switches to open loop.

How about the air conditioning?

The refrigerant manifold is completely removed and the openings are all covered. I won't spend any time or money on it until after the supercharger is installed and the tune completed.

Fuel pump? . .

James has not been able to retrieve the letter containing my check for the fuel pump and the injectors. It has not been returned by the post office as undeliverable. I'll probably order them over the phone using my charge card. I may delay installing the fuel pump until after the blower installation since my A/F ratios are good at WOT with the stock pump.

 

[2000StreetRod]

small improvement with premium fuel

I did a brief "hill climb" datalog this morning running BP Ultimate 93 octane with up to 10% ethanol gas in the tank. There was a small reduction in the maximum knock sensor retard (-6.5 vs -7.75) and it happened at a higher engine speed (3720 vs 3290 rpm). It was interesting that the knock sensor retard advanced from 0 as I opened the throttle plate in .25 degree steps and continued advancing to +1.5 degrees at 3400 rpm during WOT. The rapid drop did not begin until 3530 rpm in 2.0 degree steps. For plots see small improvement with premium fuel

Next step is to upload the desensitized knock sensor tune and repeat the hill climb. James said not to worry about it because he'll take care of it in the blower tune. He also said he will ship my high flow fuel pump today.

 

[CDW6212R]

Has James said that he likes or doesn't like to tune an engine with a knock sensor? I wonder if he would rather not have one to deal with, or if there is something to gain by having one.

 

[2000StreetRod]

no preference expressed

Has James said that he likes or doesn't like to tune an engine with a knock sensor? I wonder if he would rather not have one to deal with, or if there is something to gain by having one.

As I recall he didn't express a preference in the past although it was additional work for him and more pulls for me. We have to decide if there is actual detonation or just the sensor responding to a mechanical vibration. With stock compression, high octane fuel and low inlet temperatures we both felt comfortable that I didn't have valid detonation. The determination will be more difficult with forced induction. My Volvo turbowagon has two knock sensors. The shop manual specifies the orientation for each sensor. I don't remember seeing a specified orientation for my Sport sensor so I oriented the replacement identical to the original. I'll do some research on orientation before installing a new OEM replacement.

What concerns me is that higher octane gas shifts the knock retard engine rpm upward. That doesn't seem to support a mechanical vibration as the trigger. When my fuel gets lower I may buy some octane booster and add it to the tank to see if it shifts the knock retard up to higher engine rpms.

 

[2000StreetRod]

knock sensor orientation

I've been reading a lot of Subaru threads with complaints about over sensitive knock sensors on "built" engines. The engine looks to be an opposing 4 cylinder and the orientation is specified as to the rear and 60 degrees from the crank axis or the 4 o'clock position if the front is 12 o'clock. I read the knock sensor replacement procedure for my Sport in the shop manual and no orientation is mentioned and I couldn't tell from the drawing. Mine was at about 9:30 o'clock similar to the photo below posted by dmac0923.

And that's the way I installed the replacement. However, it looks like the orientation is dictated by the cable run more than sensitivity to a noise source. I've read what little specifications I could find on potential replacements and the BWD S8746 is supposed to be sensitive up to 1 KHz. I think I'll try it next time.

 

[2000StreetRod]

Idle air control valve

My idle air control valve (IACV) for a 2000 Mustang with 4.6L V8 arrived today. It even came with a gasket.

The inlet is the tube port.

The outlet is the bottom, unplugged port. The electrical connector appears to be identical to the one on my Sport.

 

[2000StreetRod]

Desensitized knock sensor tune better

I had a chance to perform another hill pull this morning before it started to rain. Last night I loaded the desensitized knock sensor tune and there is still 3/4 tank of 93 octane fuel. The knock sensor advance prior to the pull (+0.5 deg) was slightly more than with the stock sensitivity knock sensor tune (+0.25 deg). Unlike the stock sensitivity which increased knock sensor advance for the first part of the tune this time the knock sensor advance almost immediately dropped to zero, briefly increased one increment, and then dropped back to zero and stayed there. The max load for both pulls was 86%. The spark advance was greater than 14.0 degrees at the beginning of WOT and gradually increased with engine rpm to 17.5 degrees. As a result of the greater spark advance the time from 27.5 to 59.0 mph decreased by 0.28 seconds. My concern is that the knock sensor sensitivity may not be adequate to protect the engine if there is a sudden lean condition due to a malfunction such as a split intank fuel hose. After I burn the rest of this tank of fuel I'll put in a few gallons of 87 octane and do another pull to check for at least some negative knock sensor retard. See the following for plots: Desensitized knock sensor tune better

 

[Jakee]

You're okay if the fuel trims are good. Is this still NA?.

 

[2000StreetRod]

fuel trims are fine

You're okay if the fuel trims are good. Is this still NA?.

This is for NA and the fuel trims are fine. My concern is that the knock sensor may not be sensitive enough to prevent detonation when FI if there is a sudden lean condition - i.e. bypass fuel pump hose splits.

After this tank of premium fuel is burned I'll put in some 87 octane fuel and lug the engine in 4th gear which should cause pinging. If the PCM retards the timing then I will feel more comfortable about using similar knock sensor retard characteristics for the FI tune.

 

[2000StreetRod]

Knock sensors & blowers

I spent some time reading about various PCM strategies on the TwEECer website. I learned that overall, knock sensors on blown engines are not very reliable because the whine of the blower can cause false knock detection. From what I've read on other sites the M90 is one of the noisier superchargers. That may be why James told me not to worry about the knock sensor retard and that he would take care of it in the tune. So I guess I'll stick with the Airtex part that's currently installed and let James exercise his expertise. I'll have to rely on my wideband air/fuel ratio meter to save my engine if there's a fuel malfunction causing a sudden lean condition. I may not be able to hear pinging over the noise of the blower and exhaust.

 

[Dono]

I can't really comment on the sohc, but I can sure hear the rattling when my ohv starts detonating. I'm sure you would hear it.

 

[CDW6212R]

I think we should concentrate on making sure that the fuel pressure stays up, and the IAT's remain consistent and don't get too high.


BTW, long ago there was an A/F display product which used four lights that could be mounted anywhere. It was a good idea for an accurate A/F display, but I'm not sure that it used a wide band O2, or the cheaper narrow band O2's. I think they used the lesser sensors. That was back before the nice gauge choices we have now that all use wide band O2's.

Those four lights were colored differently, and you could place them up on the dash, or next to the instruments etc. That could be an easier method to spot trouble, if the lights were clear to see, and not obtrusive or obnoxious.

 

[2000StreetRod]

lean condition lights

My wideband A/F ratio indicator has color coded lights around the perimeter of the gauge. The top four lights are green to show within normal limits. Past them on one side is lean and on the other side is rich. Since its mounted on the A pillar its fairly obvious but doesn't block visibility. It's easily read during daylight and a little distracting at night.

Replacing the thirteen year old stock fuel pump with a new high flow pump should increase fuel delivery reliability. I think there are only about 7,000 miles on the fuel filter. The Banshee kit fuel rails form a complete loop from the fuel block that equalizes pressure for the injectors and provides flow from either direction increasing reliability.

The IAT sensor is relocated to post blower and the intercooler should help reduce the temperature.

 

[Jakee]

I've detonated the living spark out of my engine and it's fine.

 

[2000StreetRod]

injectors & fuel pump

The Siemans Deka 4 fuel injectors arrived today.

The connectors mate with the ones of my existing wiring harness. They are the long style that the Banshee fuel rail is designed for.

The Aeromotive 340 Stealth fuel pump also arrived today.

I was disappointed that application specific installation instructions have to be obtained online. I was also disappointed in the open band screw type hose clamps that I've learned from experience damage hoses when tightened. I will try to find the appropriate size German made Norma Torro hose clamps.

 

[2000StreetRod]

4th gear lock

Yesterday James Henson of Henson Performance sent me another copy of the knock sensor retard off tune with a 4th gear lock capability for dyno testing. I loaded it this morning and tried it out while running a few errands around town. It works great! In Drive under light throttle the transmission starts out in 1st when pulling away from a stop and rapidly upshifts thru the gears until 4th. Then when at WOT even at 2000 rpm the transmission stays in 4th and will not downshift or upshift when the throttle is released. However, when the brakes are applied and the vehicle speed drops the transmission downshifts to prevent the engine stalling and to allow acceleration. With this tune I should be able to get rear wheel torque values from 2,000 rpm to 6,000 rpm. The shop that did my performance testing last time has sold their dynamometer. So now I have to find another shop with a dyno that will test my Explorer - not easy to do in Upstate South Carolina.

The fuel level is finally down to about 1/8 tank. I plan to start installing the Stealth high flow fuel pump this weekend.

 

[Dono]

It almost sounds like an SCT tune mirroring the same tune modifications would be a great investment for anyone with the 4.0 sohc. Sounds like your super impressed with the changes in power and transmission manners.

That knock sensor seems like such a great idea, but maybe its just too sensitive and should have its sensitivity decreased. Ive read where some say very slight detonation (Cant even hear it) is not bad for your motor. I'm betting that even with the desensitized knock sensor that the timing would still retard if the knocking came anywhere near a level that you could hear.

Maybe this was a case of the factory engineers just being way too cautious? I'm just speculating, of course.