Devildog
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Posts posted by Devildog
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JMHO but why use EFI if the computer is not controlling the timing, particularly in a blown engine? If the EFI can't handle that important criteria then it's the wrong EFI.
These second and third generation throttle body add on EFI's do not control ignition timing (it is not designed to be a complete engine management system) you can buy the 4th generation EFI's that will interface with an electronic controlled ignition system.
Controlling ignition timing is nice, EFI to maximize A/F ratio is a much bigger bang for the buck (performance and economy).
If one wants to really do it right, probably for $15,000 buy aftermarket add-on DIGITAL ignition, EFI, etc. then your $9,000 Avanti will perform more like a ZO6 Corvette.
$2,000 EFI on my Avanti is fun and makes run a bit more dependably in Houston's hot weather. I actually like tuning the old carbs which work just fine, but stink and have hard vapor lock start occasionally. It is all just fun and the challenge of make old junk run
Joe
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Devildog (Joe), do you know what sensors the efi system you have on the car uses? Depending on things there might be some adjustments made for something like a MAP sensor so the positive pressure doesn't make things out of whack. I wonder how tuneable those efi systems are as I'm sure a custom tune would be required.
The 8.5:1 CR is perfect for a SC and you could probably safely run 5-8#s boost and not worry about hurting anything thing. 3#s might be a little on the low side. I believe the original R2 engines they ran about 5#s of boost.
Right now I'm trying to mock up (on paper) how I might do this with my carb as I think the pressurized box method might be easier as its just designing some mechanical linkages rather than the bonnet method which would require some fancy carb modifications to make sure everything was seeing the correct relative pressure. I'd love to keep my Q-jet for this, but I can always fall back on one of these off the shelf blow-through carbs.
I'm going to email Paxton and see if I can get some dimensions of the supercharger so I can start figuring how things might fit in that engine bay.
The PJ3 EFI is set-up to do turbo/supercharge engines in the software. It is a quite easy point and click input software. The mass flow sensor is built in the throttle body so mass of incoming air is computed plus O2 ratio on the feed back loop from exhaust.
I have found the EFI software is smarter than I am, just set the broad parameters and it is closed loop feedback and will 'learn' on its own better than me tinkering with it. just set the the A/F ratio and it w do the rest.
Joe
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You're right that Vortech makes a kit for chevy small blocks so that is certainly a possibility. This is really just a thought exercise at this point, but I would like to do this in the future when life permits.
Does anyone know if there was a different between the R1 and R2 carbs to accommodate the pressurized system from the supercharger? Was there a system the adjusted fuel pressure in a boost dependent fashion?
The biggest fabrication hurdle would be the brackets for the supercharger. I think the way to do it would be to move the alternator down to the lower passenger side of the block sort of where the smog pump was originally. This way the PS and AC can stay where they are.
On R2s that have been retrofitted with AC, where do they put the compressor?
I believe they mount the A/C compressor top-center on R2 289s
Joe
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This is a good idea, I have thought of doing something similar. On my 75 with the 400 SBC, I installed a PowerJection III EFI which functions nice. I would like to go to a bonnet on the EFI throttle body and use an induction tube with filter mounted for cool air source. Is there aftermarket bonnet for the EFI/carb body ???
Since these 400 SBC are only 8.5 CR, they are a good candidate for supercharging. I have not run the calculation, but with a mild 3-5 psi boost, the engine would probably increase from 200 hp/330 ft lb to 300 hp/400 ft lb. If don't go crazy with psi, it should not be big bracket to mount a Paxton blower. I replaced the old A6 A/C compressor with a modern Sanden, that bracket is tons smaller that the original. I would think a Paxton operating at a mild 3 psi would not be much more torque on a mounting bracket.
A low psi Paxton with the PJ3 EFI should be reliable and have good driveability. The 400 SBC with EFI and 700 R4 tranny performs well; however, a Paxton would add a wow factor and yield lots of style point while bench racing.
We need to do this.
Joe
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I bought a new carpet kit for my Avanti a few months ago from Studebaker International. Months later I installed and found the kit pretty good; however, there were no pieces that fit the covers on each side of A/C consul with little vents. I took a few pics including pics of the old carpet pieces for the A/C side covers.
I email the to Jim at Stude Inter and explained situation. Jim emailed me within 24 hours and sent to his vendor in CA. The vendor called and offered two options (1) send me extra carpet to have made locally or (2) send him the two old carpet pieces and he would make replacements.
I sent the old ones in a few days had the new carpet pieces. We often criticize suppliers to help them provide better products or service. However, we also need to support them when they give good service like I received.
Joe
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I bought a new carpet kit for my Avanti a few months ago from Studebaker International. Months later I installed and found the kit pretty good; however, there were no pieces that fit the covers on each side of A/C consul with little vents. I took a few pics including pics of the old carpet pieces for the A/C side covers.
I email the to Jim at Stude Inter and explained situation. Jim emailed me within 24 hours and sent to his vendor in CA. The vendor called and offered two options (1) send me extra carpet to have made locally or (2) send him the two old carpet pieces and he would make replacements.
I sent the old ones in a few days had the new carpet pieces. We often criticize suppliers to help them provide better products or service. However, we also need to support them when they give good service like I received.
Joe
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I was a freshman in high school on a field trip to the Farm Progress Show in Morton IL September 1962. Studebaker had a tent with several cars and trucks with at least 1 Avanti being the centerpiece of the display. It made such an impression on me that in April 1966 I bought a '64 round headlight Black R 1 with 5000 miles on it from our local Studebaker/Dodge dealer.
I was at the same Farm Progress Show and saw the Avanti. I thought how can anyone earn enough money to buy a car like the Avanti, seemed impossible at age 15 to go from a John Deere R to an Avanti R2
Joe
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I would just leave them alone for an occasional drive. If you are going to swap-out, I would go with the the 3:55. I have a 700R4 tranny (same gears ratios) as your 4L60 which I left the shop talk me into 3:70's It is OK, but I would like the 3:55 for 80 mph cruising (Texas has many 85 mph legal). the old rule of thumb was get a 10-12 total with 3.056 x 3.55 = 10.9 3.056 x 3.70 = 13.3 3.56 x 4.86 = 17.5 wow
With the 383 you have nice torque at 1800-2000 rpm I have an old low compression 400 cu in and get about 20 mph at 75+ mph.
Joe
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Tom,
I can not open you pics.
For future tire/wheel combos here is a great site to do the sizing info http://www.tacomaworld.com/forum/tirecalc.php
Tom, do not get too stressed the guys are slow to answer, most Avanti have not had many aftermarket changes and i would guess most owners are not as advanced as you with your nice stable of great cars...they are just a bit shy...100 looked, you are the teacher. Thanks.
Joe
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Most of the larger Pratt & Whitney and Wright radial aircraft engines run the air/fuel mixture through the supercharger. These engines have an intregal supercharger turbine disc in a 'blower case' that is on the crankshaft immediately behind the cylinders.
I have thought a SBC engine design using a combo flywheel/compressor turbine would make an efficient supercharged engine. No additional moving parts, no oiling concerns of turbo-super, no belts, no coking, nice steady 2-6 lb boost, use bleed air run the A/C.
Joe
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A 1961 Corvette with factory dual fours...You own a great car! Question...On You Corvette, is the front carb working at all at idle speed..or is it completely shut down? I'm guessing that Chevrolet used progressive throttle linkage to control these carbs...true? Thanks.
The front carb has both primary and secondary throttle plates closed most of the time; however, the front carb idle circuit is adjusted make a smooth idle. Yes, the linkage is progressive and adjustable. Most of the time you are drive just on the rear primary barrels.
Contrary to what most think, if you do not 'put your foot in to it' the mileage is quite good because with the small primary barrel you have a more controllable air/fuel management than a larger single carb. With a 270hp/283 cu in solid lifter Duntov cam (factory set-up) and 4 speed with 3:36 differential, routinely got 20 mpg at 70 mph.
I take it to the Nostalgic Drag Races once or twice a year. I shorten the linkage to the front carb so the front barrels activate earlier ('shotgun' is the terminology). Makes the car a bit quicker, but I do not push as hard as I could.
A few years ago put a DART 400 SBC and DART heads in the 61. I used ALL the original ignition, carbs, intake (hand enlarged runner), etc. It looks just the same as the original 283. It dyno 496 hp and 440 ft lb torque with same 2 x 4 WCFB carbs (350 cfm each)
I am not familiar with the manifold you are using, but heads and manifold flow have a heck of a lot more effect on power than just sticking and another carb on the engine.
Do it, an interesting project.
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I have a cheap rebuilt 700R4 behind my 400 SBC with all the emissions stripped off. Your combo should work fine...even with bigger tires, it is difficult to put the engine torque to the ground with the light Avanti rear weight. You will spin the rear wheels before you over torque anything in the power train.
If you do not have the lock-up pin in your convertor, suggest you install with a switch of some type (I just have a toggle). Reduces highway RPM 200-300 and makes tranny run cooler.
I did not change the cam in my 400, but tuned with about 18 ° of advance...much more torque, more throttle response, and runs cooler even in 100° Texas days.
Joe
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The twin Carter AFB's on this setup both have working automatic chokes with hot air delivered to both choke housings from a 'Y' connection at the manifold. Using progressive throttle linkage, would it be better to disable the choke in the front carb (leave wide open), and just rely on the choke in the rear carb for warmup....or leave it the way it is? Opinions?
Yes, I think on an AFB there are two small screws that hold the choke plate on the shaft...just remove plate.
To initially tune the car, just disconnect the linkage to the secondary AFB, get the primary AFB performing as you want. Then set linkage to bring in the secondary.
It will run OK
Joe
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I have a 61 Corvette with the original 2 x 4 WCFB carbs. I have driven it for 45 years and over 200,000 miles. As others have indicated, ned to have smaller carbs. These WCFB's are about 350 cfm each. Both have an idle circuit, and the car is quite streetable and gets good mileage.
What size carbs do you have ? If you had 400-500 cfm carbs would work OK. I do not think it would be too difficult to set-up, but I doubt you would notice any significant performance increase.
But, 2 x 4's are a big WOW facto which people enjoy
Joe
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Check the four bolts that attach the steering pivot the the crossmember. Mine were loose and the entire assembly would shift and not center. I replace with star washers to lock and eyeball centered. Had shop do regular alignment and all is good now.
Joe
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I agree, the accelerator pump is not squirting adequate fuel into the primary venturi s
Lars is the best especially on timing/ignition.
Joe
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Eric,
Great story about your father's R2. You might check with Stude International, Dan Booth, John Meyers (these vendors seem to have everything)...the people on here are wonderful about helping. Also, good info on Studebaker Drivers Club Forum.
I recently put an LS3 with 6 spd in an old rough 63 split window Corvette that I found. All my purest buddies talked of hanging me, but that power train makes such a smoother, more powerful set-up than the earlier SBC power trains.
While I had that LS3 set-up, I did the measurements to determine if I could put an LS3 in my Avanti. There are no clearance issues, except might loose a bit of the bottom of the console compartment. Since the Avanti has an X-frame there may be an issue of the drive shaft yoke being too close to the X; however, the I think the LS3 can sit more to the rear to avoid that issue. That would be great, because our Avanti's are too heavy in the front anyway.
You will have a great time with the family Avanti.
Joe
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Final report:
I reinstalled everything, bled the brakes and tried to force a leak. I saw no fluid.
I could not buy a repair kit locally for these 13/16 wheel cylinder. I used the one I removed, it is like new. I will order one and keep on shelf.
I am 95% sure it was just a leak at the brake line-wheel cylinder fitting. Flare not made correctly and worked loose
Wayne, the number "Lockheed Wagner F8418" is for the older 3/4 inch cylinder. We could not fine one for the 13/16
I cleaned the wheel and tire to remove all the old leaked brake fluid so I can monitor easily for leak.
Thanks again to all of you... my buddy that told me the front small master chamber supplied the front calipers has been shamed into buying beer and lunch.
Joe
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Gunslinger, you will be awarded an "attaboy" with cluster. Good work, thanks.
Joe
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Again thanks all of you. I just pulled the suspect cylinder and it is perfect. The cylinder is not scored, no rough spots, etc. The seal cups were new looking and the pistons were smooth with no sign of scoring. The outer seal covers were strong and appeared new. They are 13/16, I will install a new set for the heck of it.
Much fluid on tire, but not that much on the mechanicals (usually a gummy wet mess).
I am suspicious of the flaring on the brake line. It appears line was not cut quite square and flare was a bit shallow, also did not require much wrench force to loosen it (usually tough to loosen them). I filed the flare square and reflared it; hopefully, that is it.
I will report Thanks again
Joe
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Too easy, it was the drivers side rear, fluid on inside of tire.
I had the drums off within the past 500 miles while replacing the parking brake cables. All looked clean and dry with new hardware at that time.
They look like a GM brake similar to on my older Corvettes. Warren, if you have reference numbers for the cylinder rebuild kit that would be helpful rather than sorting thru the auto-parts options.
Thanks again
Joe
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You guys are good.
OK, I will check rear brakes for leaks, one of my buddies told me the the small front supplied the front calipers (I was too lazy to look at the lines).
Rear brakes were rebuilt by previous owner in past few thousand miles, but I will inspect, probably the problem.
Many years ago (about 50) I had a 54 Chevy with power brakes that apparently was some special order car even had power windows and seats. It would suck the brake fluid from the master cylinder, but it was easy to identify...the vacuum sucked the fluid into the intake and looked like a mosquito fogger. Had not thought of that in many years.
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Wayne and Warren, thanks for comments and contacts.
This brake fluid leak has got me stumped. It occurred suddenly (not progressively worse). I loose all the fluid in front resevour after about 50 miles of stop and go general driving.
I assumed a piston/cylinder seal; however, I see no indication of leak at piston in the calipers (I pulled the wheels so I could inspect). I had a helper pump the brakes and observed all lines and the calipers. Previous owner replaced the brake lines but did not replace piston seals, so no information on caliper history
Any thought from all you smart guys to isolate the problem ? Probably is a piston seal but can not see leaks, hate to throw parts at it.
many thanks
Joe
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Thanks to all of you for great information about brake Avanti components.
I have a front caliper seal that suddenly started leaking. Is the seal kit same as used in say a 63 Jag XKE ? Dunlop ?
TRW has a kit WO-133-1622306. Although the Apple Hydraulic in NY sounds like a good option to rebuild, I might do it just for the heck of it
Thanks all
Joe
Centrifugal supercharged Avanti II
in 1965-83 Avanti
Posted · Edited by Devildog
Bob, we are not disagreeing. I was saying the 2nd and 3rd gen add-on EFI's like my older PJ3, your Holley Avenger is what these guys call a 4th generation that can use timing. If you ever need any help with that Holley, the guy that designs and develops for Holley in Bowling Green is Doug Flynn. Doug is just a wonderful guy and has stayed at my house a couple of times while doing testing at SAM in Houston.
If I was buying an add on EFI today I would go for the timing interface such as the Avenger. The MSD, FAST, Edelbrock, PJ, etc all makes a pretty good bolt on system now days that can interface, even control timing. I am the great enabler and love to help my buddies buy high tech stuff for their old cars that they really do not need but just have to have.
I am one those old guys also that loves this stuff available now days. I tell the young guys if you really want to understand ignition and timing effects on performance, drive a Model T with spark advance on the steering column. The driver is the 'ignition computer', inputs are your butt and ears
Joe
Doug is a real car guy as well as smart engineer, has low 9's sec (maybe into 8's now) big block Nova with all the neat stuff.