Anyone have any experience with hilborn stack injection tuning"

 

I can get you some pointers/info.

All the sprint cars around here run 410sbc's with Hilborn or similar mechanical injection.

Dave Blainys shop is right down the road from me and I know alot of the guys that race/work on em.

 

Sorry I was asking if anybody had experience with an efi hilborn conversion. I converted my intake and had it running on a tired 350 and I started to get it to run really good until the 350 let go. I was just wondering if anybody had any tips with acell enrich( pump shot) advise? or any other tunning issues I should know about before put this back on my neew engine.

 

I've done a few hilborn and individual runner setups (straight sixes, flathead, 350, 502, maybe a few others). Best luck is with Alpha-N (TPS based load setup). Run the idle a tad rich (12.5-13:1) because some cylinders will run leaner than others at idle since not all injectors flow the same, not all ports flow the same, etc... Get WOT in the 12's. Compromise a lot in many places. Tune for where it spends most of its time. Don't over tune it because it'll change with the weather anyway.

What system are you controlling it with? I've used our companies ECU and the Carabine or whatever that comes with the Hilborn EFI. The screws controller is impossible to get near good (let alone perfect), but can be drivable - just have to do it in the right order, and repeat and make compromises all over the place, and do it on a dyno. Our EFI has a 3d table so there's a lot less compromise, and decent transient enrichment.

It all depends on what's controlling the system.

 

not to hijack or anything, but, I'm starting a big-block stack injection project. RednGold, my plan was to use a block for a vacuum source, running a hard line about 3/16" from each runner, under the throttle blades, to the block, and then putting a MAP sensor there. Do you have experience with the systems with a MAP sensor? Do you recommend Alpha-N over something like that? I'm also contemplating running a second block that has a IAC valve and running another set of line to control the idle. what do you think?

 

It'll be a biztch to get the idle down. Here's why: Each cylinder can now "see" all the other throttles when they're all spidered together. I'm not saying it isn't possible, just that I've tried it on 2 different setups and the idle MAP was terrible (inaccurate reading), and the throttles had to be closed which means they aren't quite equal, and it's very easy for them to stick or bind. I didn't make the setups, just tried to tune them, and quickly switched to Alpha-N (and open loop). Maybe some more time and I could have gotten better results (maybe try sampling one cylinder, two opposed cylinders, maybe restrictive orifices in the tubes, etc..) Could build the IAC into the same middle block as the MAP sensor.

IR setups in general are a lot of maintenance to keep them sync'ed. I wouldn't want it as a daily driver either.

 

I am using the 1227730. Idle was quite nice and it was very streetable. I have an aluminum block machined to the exact specs and threads of the iac that would fit a gm tpi or tbi. It then channels underneath the intake into another aluminum block with a hard line to each intake port. map is also ported to this block. It idled at 60 to 68kpa with 288 adv duration camshaft. Idle was great. It was difficult to light cruise with because at the speed limit the throttle was barely moved and had extremely low tps voltage (.88 to1.2) I think. When I smashed the throttle power kicked in like a firecracker. This set up was still waaaay out of tune and it still ran better and saved more fuel than the 4bbl carb it used to have on it. It has 2 3/16 throttle blades and was starting to get the tune really nice in closed loop.

 

cool, thanks for the all the info so far guys. I'm not going really radical, but I'm gonna see how it all works out. I'm planning on using a progressive linkage, to hopefully get something reasonable with drivability. I probably will run idle open loop, and may not even use the IAC, if i see issues, so I have some options. Its good to know I can run the MAP and IAC off the same vacuum block. should save some headache. It'll be run on a '730 BTW.

 

I finished my stack injection system and it is awesome. With it not even perfectly tuned I ran 11.98 at 111.1 mph. PE was set extremely rich just to be safe. I slapped it together in hurry to get it to the track before it snowed I got 2 runs in and the snow fell and the track closed for the season. Canadian weather sucks!
I will get it tuned better and let you know of any improvements in the spring.
The follwing saying I made up is sooo true>>> Once you go stack, you'll never go back.