It's gonna be really close, even after milling. Looks like I'll be cutting no matter what.
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It's gonna be really close, even after milling. Looks like I'll be cutting no matter what.
Could always shim the K member down a little with a washer.
I have a dilemma...
http://i1081.photobucket.com/albums/...psbe94668a.jpg
The Edelbrock and Professional Products fuel rails are both the wrong spacing for the Motown intake. I measured up the stock rails and the dimensions are even weirder (especially because the injectors are slightly angled). So this means I need to make my own fuel rail which is no big deal. I already picked up the extrusions for pretty cheap.
I have 2 sizes to choose from which are for -6an and -8an o-ring fittings. The stock LT1 fuel lines should be plenty (only 3/8" or -6an) with another 255 added in-tank. I'm leaning towards the 6an extrusion rails run in parallel but I'm a little bit concerned.
Cross sectional area
LT1 rail (<5/8 ID) - .307
Edelbrock rail (9/16 ID) - .249
6an (1/2 ID) - .196
8an (11/16 ID) - .374
The 8an rail in parallel is definitely wayyyy too much fuel. Hard to really put a power figure on the 6an rails but I keep seeing the 11/16" rails rated at 2000+ hp on v8 engines. Is it safe to assume that the 6an line is capable of 1000+ on an engine with the same bsfc being that it contains half the fuel? Another thing to consider would be pulsation in the rails but I don't think I should be worried with dual pumps, a parallel system, not crazy RPMs, and FPR with built in damper.
I would stick with 6an rails, you will save on getting a ton of 8an stuff and its really not needed.
Step up the feed line and return line size if you are worried. Otherwise, I wouldn't worry, I have no issue with 6an and my rails aren't even parallel.
Simple is, as simple does here.
It's less so the feed/return line that worries me and more the volume of the rail itself. Pressure spikes from injectors opening/closing that have to be replenished through the tiny 6an orifice. I was thinking about maybe drilling out the ends large enough to fit a 8an barb (.44 ID vs .34, twice the cross section) and then having it welded in but IDK. Maybe the pressure spikes are nominal when the rail is nearing 60psi with a FMU.
Wish I knew more about fluid dynamics... didn't think I'd ever say that lol
Quote:
Originally Posted by Catmaigne
Missed the CSA on the 6an rail, thats small...Quote:
Originally Posted by Catmaigne
I have edelbrock rails, with 6an feeds and they have not been an issue. I retract my previous statement and say go with large rails with stepped down fittings to 6an. (its been a couple stiff sailor jerry drinks night :lol:)
You don't have access to CFD at school? Toughest part will be modeling the pulses.
I do but I'm on thanksgiving break right now! I'd have to find someone to help me too lol
What sucks is that there are 9/16 and 5/8 ID rails out there but neither are cheap compared to the Ross extrusions. I feel like the gigantic 8an rails will give me less headroom with the fuel pumps because it's more volume to pressurize. Might have to bite the bullet and get the expensive ones.
Finally got around to pulling the motor out of my car. #8 rod bearing was spun. Now it's rebuild time! Probably just gonna use my block because my search for a reasonably priced core has been unsuccessful.
I also scored a set of almost new Siemens Deka 60lb injectors on eBay for $190. One more piece of the puzzle.
I completely tore down the motor in the daylight to see the full extent of the damage. Not only was the #8 rod bearing toast, but there was another rod bearing that was horribly worn and the #2 main was so trashed that the crank journal is burnt. The motor still had acceptable oil pressure but I knew its time had come when it developed what sounded like a tap and dropped about 10psi of cruising oil pressure. Doesn't look like the debris damaged anything else in the motor, everything else looks great.
Here are the injectors... "60lb" Siemens Dekas aka Mototrons aka Accel aka Edge that actually flow 63.5 lbs/hr @ 3 bar. This will get the job done and should have good idle quality.
http://i1081.photobucket.com/albums/...ps19aa0720.jpg
I haven't had much luck selling my Mahles to finance the custom pistons. Being that they couldn't be returned and I didn't want take a hit by selling them for super low, I've decided to run them with shorter rods. The 5.85" Eagles were an absolute steal when purchased and I could easily turn a profit on them. I ordered another set of Eagle 4340 H-beams with the same ARP 2000 bolts in 5.7" length for $440 (yay, black friday!!!!) so now I can use my Mahle kit. I've been pretty indecisive but that was a compromise that I had to make if this car is going to be back together before next spring. I don't have time to peddle parts and don't think the change in rod length was significant enough to lose sleep over.
I've also decided on using the gargantuan Ross 8 fuel rails I already have. Can't seem to find any negative side effects of having more fuel volume present in the rails. Overkill but it works.
Also, I did more mocking up on the intake.
https://scontent-a-lga.xx.fbcdn.net/...e3&oe=55170B9E