Ok. Guess it's time for another update.

[Shoprat]

Ok- where to start ? After mulling over ideas on proper pistons to install from here and other locations, I decided to go with Keith Black Hyperutectic pistons in the stock configuration resulting in a 9.5 to 1 compression ratio. Why do this in a Turbo when most people with good sense lower compression ratio to accomodate the boost? I was going on what I observered before the stock pistons collasped due to too much timing. I was running almost NO boost pressure at the 55 mph speed rate. If I went with the dished pistons, I would lose power when the engine was in normal asperation mode. So, I went the higher compression way.

Keith Black reccomends a drop of 2 to 4 degrees of timing for their hyperutectic pistons . Seems they run coooler than stock pistons and so this is necessary. So, I got the MH running and was finally able to take it down to Backwoods Racing to have the new configuration mapped into the SDS Fuel System computer. This time, Don ( the mapper), said it would probably be done more quickly if a fellow named Andy did the driving as he was familiar with the area and what they were trying to accomplish. I considered this request, and figured that I must have really scared Don the last time . I said ," Sure, go ahead."

I guess I should also mention that my heater blower wasn't working and it was 35 degrees . So it was kinda chilly in the MH. I accompianed them in the Gramma seat in the back as they drove the MH around Midland under road conditions. So, the two of them went at it. It was fun to watch these guys work together. Seemed like they had the same procedures running through their heads at the same time. Comments of , "Thats enough"- "More there"-" Still doggy"-" Dead spot"- " Hows that"- "Zero to one negative map dont happen-I know that"-back and forth. All in all, kinda like watching a football game in an open air stadium, temperature and all.

Well , they got it mapped. Don told me that I should go to premium gas to be on the safe side. And should also go one or two heat ranges colder on the plugs. Said to try it for a while and see how it suits me. Possibly would have to do some more tweaking to really lock it in. I agreed and he presented me with his bill, 2 1/2 hours mapping= $106 . I looked at him in disbelief. That sounded too darn CHEAP ! I told him he was working with the MH for at least 3 1/2 hours anyway. He informed me that the first hour, they were just getting their equipment set up correctly for the road testing- no charge for that ! Criminey.

Well, anyway. I drove it home and filled it full of premium fuel. I drove it 50 miles and refilled it. 5 gallons of gas. A little dissapointed in the mileage. Power seems good, but maybe could be improved some. Doesn't seem to want to accelerate at full throttle and 5 pounds of boost. I have thought about this, did some checking on the internet, and found very valuable info.

Keith Black has a site where you can figure your total compression ratio using static compression and boost. Going with the info from my piston number and my engine head c.c., I came up with 12.1 to 1 . This is just below the ratio they consider max for Premium pump gas. Cross checking with the LC Engineering site, at this comp. ratio, they recommend a 7 heat range NGK plug, I am running the stock 5 heat range plug. Also, on another turbo site, they recommend going down thinner on the spark plug gap- from the stock .032 to .025 or even .022 at up to 20 psi boost. The boost has a habit of blowing out the spark at wider gaps. Could be where my lack of power on acceleration comes from. Also the cooler plug allows you to up the timing some without detonation. So, I ordered some NGK BKR7E spark plugs and will gap them at .025 and see where that leads.

So, all in all, this MH upgrade has been a VERY interesting experience. Expensive, but interesting. The looks I get when I tell people I put a turbo in a mini-motor home are priceless. They invariably ask me why, and I answer that I want to enter it in a drifting contest.

[nolan]

Ok- where to start ? After mulling over ideas on proper pistons to install from here and other locations, I decided to go with Keith Black Hyperutectic pistons in the stock configuration resulting in a 9.5 to 1 compression ratio. Why do this in a Turbo when most people with good sense lower compression ratio to accomodate the boost? I was going on what I observered before the stock pistons collasped due to too much timing. I was running almost NO boost pressure at the 55 mph speed rate. If I went with the dished pistons, I would lose power when the engine was in normal asperation mode. So, I went the higher compression way.

Keith Black reccomends a drop of 2 to 4 degrees of timing for their hyperutectic pistons . Seems they run coooler than stock pistons and so this is necessary. So, I got the MH running and was finally able to take it down to Backwoods Racing to have the new configuration mapped into the SDS Fuel System computer. This time, Don ( the mapper), said it would probably be done more quickly if a fellow named Andy did the driving as he was familiar with the area and what they were trying to accomplish. I considered this request, and figured that I must have really scared Don the last time . I said ," Sure, go ahead."

I guess I should also mention that my heater blower wasn't working and it was 35 degrees . So it was kinda chilly in the MH. I accompianed them in the Gramma seat in the back as they drove the MH around Midland under road conditions. So, the two of them went at it. It was fun to watch these guys work together. Seemed like they had the same procedures running through their heads at the same time. Comments of , "Thats enough"- "More there"-" Still doggy"-" Dead spot"- " Hows that"- "Zero to one negative map dont happen-I know that"-back and forth. All in all, kinda like watching a football game in an open air stadium, temperature and all.

Well , they got it mapped. Don told me that I should go to premium gas to be on the safe side. And should also go one or two heat ranges colder on the plugs. Said to try it for a while and see how it suits me. Possibly would have to do some more tweaking to really lock it in. I agreed and he presented me with his bill, 2 1/2 hours mapping= $106 . I looked at him in disbelief. That sounded too darn CHEAP ! I told him he was working with the MH for at least 3 1/2 hours anyway. He informed me that the first hour, they were just getting their equipment set up correctly for the road testing- no charge for that ! Criminey.

Well, anyway. I drove it home and filled it full of premium fuel. I drove it 50 miles and refilled it. 5 gallons of gas. A little dissapointed in the mileage. Power seems good, but maybe could be improved some. Doesn't seem to want to accelerate at full throttle and 5 pounds of boost. I have thought about this, did some checking on the internet, and found very valuable info.

Keith Black has a site where you can figure your total compression ratio using static compression and boost. Going with the info from my piston number and my engine head c.c., I came up with 12.1 to 1 . This is just below the ratio they consider max for Premium pump gas. Cross checking with the LC Engineering site, at this comp. ratio, they recommend a 7 heat range NGK plug, I am running the stock 5 heat range plug. Also, on another turbo site, they recommend going down thinner on the spark plug gap- from the stock .032 to .025 or even .022 at up to 20 psi boost. The boost has a habit of blowing out the spark at wider gaps. Could be where my lack of power on acceleration comes from. Also the cooler plug allows you to up the timing some without detonation. So, I ordered some NGK BKR7E spark plugs and will gap them at .025 and see where that leads.

So, all in all, this MH upgrade has been a VERY interesting experience. Expensive, but interesting. The looks I get when I tell people I put a turbo in a mini-motor home are priceless. They invariably ask me why, and I answer that I want to enter it in a drifting contest.

Hey Shoprat, Glad to hear your back on the road. Geezzz, I,m jealous, doing the dial in with a computer, makes my old plug reading, jetting, and carb tinkering kinda antiquated by todays standards Bottom line, we both shoot for the same end results, no meltdowns.

Actually I have been very happy with the supercharger, no problems to date, run premium fuel, no detonation, stock plugs, did go to a aftermarket performance ignition and coil as it was loading up at idle, but with the hotter spark thats a thing of the past now. I,m running 6# boost and at cruise on the road I,m not into boost, probably will benefit the longevity over time, fuel mileage I'll have to brag a bit over yours, granted your a bit heavier, but I,m running 4x4 with 33" tires and averaging a respectable 17. I,m going to do a tranny swap come better weather, so I might even improve on that a bit, gonna do a turbo truck 5spd with the lower 1st gear, will benefit on both ends, lower first for takeoff and 5th for cruisin. But as these projects seem to do, while I,m doing the tranny, might as well build some sort of fancy console, add some more gauges, it never stops.

Merry Christmas

[Shoprat]

Merry Christmas right back at'cha Nolan. And the same to all the regulars here.