Lifted79CJ7
Blown7
As I have found this type of article only uses a dollar value to hook you in "under 900 hundred dollars" what they don't tell you is yea he spent some time researching but not exactly how much time. I had spent 2 yrs self educationg myself on boosting pressure to a N/A engine before I began my project. If you can find someone already knowledgeable to help you it will go along way to making your dream happen sooner. Now myself after having done it a number of times it is easy, but then again maybe brain surgery is easy to a brain surgeon. It can be done but to do it correctly the first thing is, design the engine around the cam, perferably a blower cam grind, which incidently is just around any engines factory specs with just a little tweaking. Jeff
Lifted79CJ7
OK Jeff, you just opened up your own bag of worms!! So thinking along these lines with a 401, where should someone like myself start at? Any recommendations/steer clear of's? I do know about being careful of thin cylinder walls, etc, but I don't want to run that much boost - maybe around the 5 psi range. I have been interested in budget boosting for a while but just haven't had the time or funds for a project like this. Now I am starting to get close to it. So what do you say - up for a turbo 101 for AMC engines?????
:wink: Pleeeaaaassse?!?!?!?!?!?
Jack
Blown7
Ok sure first question, Why a turbocharger? I myself am in favor of superchargers myself. First Turbo's won't give you any bottom end torque. They only start producing good boost when it spools up enough usually in the 3 to 4 grand range. Then they start making boost. They restrict exhaust gas flow and actually are a hindrence at low RPM's. They are hot, run hot, and require a cooling oil flow that if to get longevity you must allow a cooling period at idle before shutdown. If the turbo "lunches it could contaminate the engine oil supply. If the seals fail it could suck your sump dry. Plumbing can be a nightmare. On the plus side they are free horsepower using the gas flow as a powersorce. They work well with carburated engines. Intercooling is easier. Now to answer a question about thin walls not a problem with low boost (under 8 pounds with 8:1 compression) the magic number to stay under for total compression on pump gas is 12.5 to 1 (engine compression plus boost). 5 psi is almost a no brainer. Next question? Jeff
Lifted79CJ7
OK, then what about a supercharger (not a roots style, something like this?
My thought is a budget builder and can it be done. When you start talking superchargers, you don't see too many decent shaped used ones at a decent price. And do these work well with carbs?
Question three - what changes need to be made to a carb?
Question four - what about cam grinds for an AMC V8 (401)?
Blown7
That is a centrifical supercharger, belt driven yes its probably the easiest to install and works well, agin the only plumbing you have to worry about is from the charger to carb. Question 2 The same applies whether it is a Roots, turbo or centrifical, if its for sale chances are its been lunched, I haven't met anyone who has removed a boost system because it worked too well, the thing you have to watch out for is if the engine had a backfire thru the charger bad things happen to the castings, (read junk) a engine that backfired will literally under the right circumstances grenade the charger, on the Roots I have I have a burst plate to act as a safety valve with low to moderate backfire and it hasn't burst yet but if it does I hope it may save the 6-71. Backfire results from running lean which is very easy to do with a boosted engine. (Thats why I went with a Fast EFI programmable system) less hassle and I can tweek if I want to barometric pressure and temperature. Q3 Carbs can be divided into two basic systems, Blow thru and Draw thru each has its good points. First blow thru is the easiest system to build but the things that need to be changed are , the float may collapse so it must have a solid float Second forget vacuum anything, (brakes, distrubutor advance, heat controls, QT valves) there ain't any. All the system is positive pressure (we call that on aircraft supercharged systems "upper deck pressure") also all the connections to ambient pressure must be plugged to prevent leaks even the throttle shaft bushings need to have air under boost by drilling a passage from the outside and plumbed tto the positive pressure side. Now if there is a return charcoal canister for fuel vapors you have install a check valve in the line to prevent fuel vapor under pressure from returning to the fuel tank and bypass the line to the aircleaner. Now you have to use a electric fuel pump as the pressure rise with boost will not allow a mechanical pump to overcome the increased need for fuel pressure and quanity several ways to do this a rising rate fuel pressure valve is one as the boost increases fuel pressure rises to meet the increased demand of the engine and to keep the vinton valve closed ( if the pressure rises too much the valve may never seat. The fuel line will need to be resized to allow more fuel flow, a 3/8" line ain't gonna cut it. (To cut to the chase my 401 ci uses roughly 800 ci of air under 10 psi boost) yes thats right I have a 800 ci AMC! so if BSFC is .5 lbs per hp we are talking some heavy fuel rates. Also conside the PCV system the system as OEMed will build up crankcase pressure unless you vent the breather back to the air cleaner. This ain't all but we'll move on to draw thru the carb mounts ahead of the compressor inlet so the charger draws the fuel thru the carb in normal atmospheric conditions all the stock pcv connections can be retained you'll have vacuum, but now the location of the carb is changed so you have to deal with modifing that, the heat riser will now be useless as the carb will be a disatnce away and fuel will not vaporize well when its cold so cold startup will be a problem, not to mention carb ice on a moist humid day because of the airflow thru the venturi now we are talking plenums to keep heated air around the carb. Then in some instances you'll have unequal fuel disribution unless a screen is installed before the intake runners. Then the carb has to be sized and jetted to allow for the increased fuel air mixtures ( the stochiometic mixture stays about the same but the Pounds per hour of fuel goes up, (all this is to prevent detonation the killer of supercharged engines nothing will grenade the engine in nanoseconds like a lean mixture) thats why we run long reach plugs to act as fuses, the tips burn off hopefully before bad things happen to the pistons and rods. Thats why EFI is sooooooo mucher easier to program. Q4 cam grinds ah thats a mysterious art often elusive yet so satisfying, BS first chat with Richard Iskedarian ( I have his number if you need it) the cam is gonna revolve around the basics that your misson profile will require, you can have it all but you pick your needs, first and number one you want a 110 degree overlap thats the biggie, any more any less messes up the volumetric efficency of the engine. Next lift, you don't need alot somewhere around .500@ .050" is fine actually I think mine is .523 (in most instances a stock cam grind will do fine) If you want I'll dig out my cam spec sheet. After a bunch of typing and maybe you reading their is yet a whole bunch I haven't touched on yet maybe your understanding now why the supercharger kit manufactors charge so much, somebody has to do all this engineering, design and testing to make a viable useful system. One of the reasons I went with a 6-71 is its actually simpler to design and make a pretty bulletproof system. Another was the EFI, to put it simply carbs suck, in more ways than one I'm tired of screwing with them they wear out, get dirty, difficult to adjust and tune for boost. Ok with my ranting out of the way what exactly were you planning to supercharge? maybe I can just point my thought in a specif direction. K have a good evening and will be standing by waiting for further questions. Jeff
Dusty
Jacks been wanting to turbo his AMC 401 :lo1l: now im listening jujst to see where this goes sounds very interesting. thanks for all the tid bits
Lifted79CJ7
Holy cow Jeff! that was a novel! I love it!! This is the type of info I am looking for. Well I am probably just thinking of the same thing as you - forced induction 401 in a CJ7. So how is cooling that much engine? Also, when do we get to see pics of that bad boy!!!! So do you have nice little butterflys sticking up through the hood??? :t:
Jack (still processing all that info!!)
73hornut
jeepsr4ever
Looks like it will take alot of work to get that engine in a vehicle
Lifted79CJ7
Yeah, I read his whole writeup on the FSJ forums and it og going against the budget boost idea. I guess for the most part is just isn't gonna happen, but I have read enough to know it can be done - you just have to know your sh!t. And there is a lot of sh!t to learn!! :!: The question lies in how bad do you want to do it.....
Blown7
Ok Jack, I can give you a long winded novel on the boost side, but as I said before I don't think turbo on a 401 is a no brainer, and not cheap. I looked at the engine pic on the stand, I do agree with MC I'd like to see that installed first, not on a stand. By far the cheapest way is to get a 6-71 package from either Dyers or BDS and you get all you need and even then you'll have to do some work getting it all to work. I gotta get a new digital camera and I'll send some pics. Yes I do have a bugcather thru the hood, actually I'm going to make a internal aircleaner under the bugcatcher so I won't hide those beautiful butterflys. Now speaking of butterflys another thing even I didn't plan on was when BDS set the kit they welded one of the butterfly intake chambers closed so that only two butterfly valve passages are open for airflow, a 401 don't need three. See even after two years somethings even I missed out on. Now my newest dilemma is to try to get a new MSD crank trigger into my crank drive setup, around all the OEM pulleys (A/C,PS) ,I have a Accel DFI distrubutor with Hall effect but I want precise ignition triggering that only a crank trigger can give, the Vertex is too wasteful (the timing can be more controlled without so much retard especially with wideband O2) see it never stops. Then to send the ECU back to FAST to have the box reconfigured for crank trigger. So you still wanna talk Turbo? Jeff
Lifted79CJ7
:shock: Heh heh heh, horsepower is cool! Looks like there is just a lot more to learn....
Lifted79CJ7
Blown7 wroteI looked at the engine pic on the stand, I do agree with MC I'd like to see that installed first, not on a stand.
Here are the pics of the install of that setup in the waggy. Daddy likes! :wink: I am with tarior on this one. I am bound to figure this all out. It might take 10 years, but it will happen on the low buck just to see what I can come up with a little inginuity. I am just hell bent on slapping on either a small belt driven supercharger or a turbocharger. I'm not looking for anything crazy, maybe 5psi of boost. :-| Blown, I'm gonna have to pick your brain in detail one day here soon!! I would just like to figure this out before I rebuild this 401 in my garage......
Blown7
I saw the pics and Wow, quite a setup, having spent alot of time workin and modifyin Waggys myself it was well designed. I bet the time designing and thinkin must come to hundreds of hours to make a fit like that. Again it can be done but his line item list on hard cash came to what? 10-15K? Never mind the free time an' effort. It can be done. His only downfall I see is, Hankrod should never get into even a 5 MPH front end crash or hit a deer. Now for a economy setup. Lifted, start lookin for cheap EFI system or make one, centrifical charger or GMC 71 series and start gathering the plumbing. Jeff
Blown7
I found a couple mock up pics of the 401 as I was cleaning out the old office computer who wants to get a email and post em? Jeff[/list]
Mudrat
Blown7 wroteI found a couple mock up pics of the 401 as I was cleaning out the old office computer who wants to get a email and post em? Jeff[/list]
PM sent to ya Jeff - I'll host'm
Pat
Blown7
I sent the pics, did you get them? Jeff
Mudrat
Blown7 wroteI sent the pics, did you get them? Jeff
Nope - just checked all my e-mail, haven't seen'm ... yet :-|
But at 2AM the server may have been sleeping :shock: What the heck were you doing up at that time of the morning anyway? 111!!!
I'll give it a couple hours and see if there was a mail-server issue that was cleared and they come thru . I'll give ya a different addy to send them to just in case. Check your PMs
Pat
Mudrat
Up late and sleeps all day - but he gott'm here :shock: These are Blown7's 401 Pics :shock:
Outta be good for at least a mid-13 time :t: On pump gas no less~!! :?:
