There is more than one Spectre plenum. I'm pretty sure the Jeep plenum was taller than the one I picked (not the common one people usually get). I kinda wanted the 4" hose size, though it was definitely more challenging to route out of the engine bay.
Be aware that the jeep plenum being shorter needs a spacer to allow the air to make the 90 degree turn into the throttle body. Early users (including me) noticed a decrease in power/performance after installing the Jeep plenum. I used a piece of plastic pipe (green in the photo link) to provide this space and it fixed this issue.
I had read that. I asked Kelvin about it and he indicated he hadn't had any issues with his Jeep plenum on his FiTech system. So I didn't use a round spacer. It seems to work just fine. We shall see how things progress. He DID indicate I will need that spacer if I ever have to re-install the carb for emergencies and want to use the plenum rather than keeping the 14" filter/housing onboard.
Don't worry about delayed relays or manual cutoff switches.
I've been looking for a better solution, like a box style from a GM pickup.
Depends on the design of the throttle body you are using. I'm using a GM Rochester from a 454. The air must make a tight 90 degree downward turn into the driver's side TB barrel within an inch or so. It needs a spacer so the plenum can clear the injectors, so I just made it a bit higher.I had read that. I asked Kelvin about it and he indicated he hadn't had any issues with his Jeep plenum on his FiTech system. So I didn't use a round spacer. It seems to work just fine. We shall see how things progress. He DID indicate I will need that spacer if I ever have to re-install the carb for emergencies and want to use the plenum rather than keeping the 14" filter/housing onboard.
I will say I seem to have more ready power than I had before. It pulls HARD! I set the idle at 750 and it keeps around there after warm-up when idling. EFI really "woke-up" this vehicle.
I'll have to listen carefully next time I start it. What with the draw from pressurizing the surge tank and the draw from the compressor, my single type 78 battery (new last summer) doesn't seem to have enough "oomph" to crank the starter sometimes. The compressor comes on even before I crank the starter, taking the edge off of the battery for cranking. It's making me re-think the plan to remove the battery "boost" system. A second battery seems to make the difference.
I definitely like having that present as a backup option, just in case I do something stupid to the engine battery.
Check the voltage on the actual battery during this condition. It's possible you're just seeing localized voltage drops due to shared grounds or shared power feeds between the EFI and the compressor. If that's the case, you may want to separate them.
I haven't check pricing for a starter; I assumed they were much more expensive. I'll just get a new one to refresh the system.
I haven't check pricing for a starter; I assumed they were much more expensive. I'll just get a new one to refresh the system.
The EFI system is not chassis-grounded; both +12 and grounds go directly to the battery. I wanted to give the system the best chance of working (many of the complaints about this system come down to poor voltage/connections). I'll relocate those connection one by one after an initial break-in period.
I have installed three batteries since I acquired the coach in 2023. The only time the starter was happy was when I used "boost" or the batteries were freshly charged (plugged-in). The current battery is less than a year old.
Never run any accessory ground direct to the battery (unless you are absolutely sure its power ground is floating internally).
The last quote I got for a local starter rebuild was $240 several years ago. About 10 years ago I had one done for $70, but that place closed down when the owner retired. Maybe it's a West Coast problem, but it's not always easy to find a reasonable independent shop anymore. I'm hanging on to the original still just in case. The AC Delco starter was inexpensive enough and has worked great for the last few years.
I'm finding rebuilt Delco on RockAuto and AutoZone. $55 plus $25 shipping at Rock, $95 at AZ. That's without a core swap.
When Paul Lambke got out of the GMC engine rebuilding business some years back he brought a list of parts for sale to Ernie Dankert's rally and he had one of those for sale. High dollar item! I'll ask him if he has a part number.
Didn't hear back from Paul but JimK has one and you know it'll work.
