Author Topic: Rear Engine Modified Roadster Build  (Read 290131 times)

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Offline maguromic

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Re: Rear Engine Modified Roadster Build
« Reply #120 on: November 06, 2009, 10:23:17 PM »
Yikes! 18" . . . but great for the salt.  :wink:
What oil filter are you going to run and where located? Incorporated into the tank?

I am not worried about the length as it wont effect the amount of torque the shaft will take.  It makes the “springiness” of it change, but the cross section (limited by the spline section) is not changed.  If gets very long, you get a different issue, but this isn’t all that long compared to the length of a half shaft which may carry 3-4 times as much torque.  Plus, I think the CG issue is very important in car stability and we needed to shift the engine a little forward.  You hit the nail on the head, its great for the salt. :-)

One of the spots for the dry sump tank we have looked at is in between the trans axle and the bell-housing.  Need to figure out a way to bring the two scavenge lines from the pump to the tank without aerating the oil? One idea I have is to snake it around like some NASCAR tanks. But its a lot harder on a square tank than on a NASCAR style round tank (if you want I can post a picture of what type of NASCAR tank I am talking about). Another problem we have is anticipating the future needs and trying to build for it.  But I think a 5 gallon capacity tank should do the trick, a little overkill for the GMC.

I am not an engine guy, but having been around some dyno testing on filters and filter mounts I know if we don’t do this correctly we can loose HP, and on HP limited motors that can be huge.  Any ideas let me know. Tony
« Last Edit: November 06, 2009, 10:25:28 PM by maguromic »
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saltfever

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Re: Rear Engine Modified Roadster Build
« Reply #121 on: November 07, 2009, 06:08:17 AM »
If I understand the principal correctly (not guaranteed :-D);  surface tension helps to remove air entrainment. Basically, if the oil could be spread out on an unlimited flat surface the thin film develops less surface tension than the bubble surface area and it bursts. The conical form inside round tanks is just trying to package as much surface area in as small an enclosure as possible. I have been considering a square tank for packaging reasons. I think an Oberg 60u screen set-up, welded into the top of the tank, would help in filtering out (or breaking up) the bubbles. After that the oil would flow onto a set of baffles to continue the release of air.

http://store.obergfilters.com/8inch.html

60u is just about my bearing clearance. I don’t want 60u particles passing through my bearings and will filter it down further. The problem is the pressure drop and whether to put a finer filter in the tank or an additional filter inline.:|  I would like to do an experiment with a Plexiglas window or sumptin to see what is going on. Don’t know if it will ever happen, though.



Offline krusty

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Re: Rear Engine Modified Roadster Build
« Reply #122 on: November 07, 2009, 06:25:06 AM »
" I have been considering a square tank for packaging reasons. I think an Oberg 60u screen set-up, welded into the top of the tank, would help in filtering out (or breaking up) the bubbles."        This is exactly what our engine builder, Keith Dorton of Automotive Specialists, uses on his dyno. The dyno oil tank is shaped like a "V" and has a pair of 8" Obergs (mounted horizontally) forming the top. It also has a plexi window in the front for observation. You can see that the Obergs deaerate the oil extremely well. I will probably create a similar tank for next year's racing as it will solve several small problems in our RMR.   Tony, say hi to Sean Mclean for me .  vic
« Last Edit: November 07, 2009, 06:27:40 AM by krusty »

Offline maguromic

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Re: Rear Engine Modified Roadster Build
« Reply #123 on: December 11, 2009, 11:06:09 PM »
It’s been a while since I updated the build and finally the bell-housing package has been finished and I have something to post.. The big difference from the earlier design is we have added a rear support for the starter motor.  The only thing left is to design some type of support to hold everything up when the engine is removed.  Tony

This is the GMC 6 and IRL Aurora rear engine plate.


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saltfever

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Re: Rear Engine Modified Roadster Build
« Reply #124 on: December 12, 2009, 12:39:20 AM »
Wow! Tony. Take all the time you need to make beautiful solid models like that. It is worth the wait.  :-D

Offline bvillercr

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Re: Rear Engine Modified Roadster Build
« Reply #125 on: December 12, 2009, 01:16:22 AM »
Hey Tony, is everything still in the design phase or have you started the build side of the project?  Looks like your gonna have one special roadster can't wait to see it completed.  :cheers:

Offline mkilger

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Re: Rear Engine Modified Roadster Build
« Reply #126 on: December 12, 2009, 12:20:38 PM »
Troy you said it before I did, lets see some photos of your build looks like its going to be trick.

Offline maguromic

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Re: Rear Engine Modified Roadster Build
« Reply #127 on: December 12, 2009, 08:06:24 PM »
Troy and Mike, we are still in the planning stages and only recently started machining the suspension parts and making some of the tanks.  We still have to draw the chassis and water tanks. 

A bunch of friends are building this for one of our good friends. Other than me the others all work on different teams during race season and have only a few hours here and there to work on the car.  My work takes me away out of the country often and leaves little time to work on it as well.  I think at the rate we are going it looks as though it will be 2011 when the car will run.  But I will post updates as the parts get finished and just maybe it might run in 2010.

I have been leaving the frame for last as that is the toughest part for me.  I want to design it in a way that the driver cell is protected from any scenario that can be thrown at it.  Keeping that in mind we have designed all the other parts to work in unison. Currently we are leaning towards a structure that can progressively collapse absorbing the energy without compromising the driver cell.  I hope to have the frame drawing uploaded  soon for comments.

Saltfever, thanks for the compliment. The pictures below are of the bell housing in the car. Only the back of the frame where the suspension and trans axle attach are finalized.  The other tubes are just there to show how the engine will fit.  The two engines that are drawn are the GMC 6 and the IRL Aurora. Tony





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Offline SPARKY

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Re: Rear Engine Modified Roadster Build
« Reply #128 on: December 12, 2009, 09:07:57 PM »
I suspect that a WHOLE bunch of folks are going to STUDY, admire, and stand in awe of this one,the RPM's that you plan on turning that 302 without turning the crank into "shatter glass" got my attention. :cheers:
« Last Edit: February 05, 2010, 11:10:04 AM by SPARKY »
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

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saltfever

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Re: Rear Engine Modified Roadster Build
« Reply #129 on: December 12, 2009, 10:42:13 PM »
I suspect that a WHOLE bunch of folks are going to STUDY, admire, and stand in awe of this one RPM that the plan on turning that 302 without turning the crank into shatter glass got my attention. :cheers:
Huh!  :? :?

saltfever

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Re: Rear Engine Modified Roadster Build
« Reply #130 on: December 12, 2009, 10:46:00 PM »
Tony, that alternator ratio looks something like 3:1. Assuming a shaft speed of 2,500-2,900rpm do you need to spin the alternator that fast?

Offline maguromic

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Re: Rear Engine Modified Roadster Build
« Reply #131 on: December 13, 2009, 02:10:25 AM »
I suspect that a WHOLE bunch of folks are going to STUDY, admire, and stand in awe of this one RPM that the plan on turning that 302 without turning the crank into shatter glass got my attention. :cheers:

Sparky, We are making our own rods, crank and bottom girdle to help keep it from flexing. One of the ideas we have been playing with for the crank on the GMC was to build an even fire crank for it.  Currently the firing order on the GMC is 1-5-3-6-2-4.  We want to run it like an old Norton or other British twin and bring both cylinders next to each other up at once and fire the other at 120 degrees.  So the new firing order would be 1-3-5-2-4-6. Basically it would be like having three two-cylinder engines hooked together.  Another plus side  would be with the even fire crank the siamese intake problem of the stock style head could be solved with the full intake charge going to one cylinder.  This is nothing new, I think JD mentioned sometime ago that Bruce Crower had a similar design.  Tony


Tony, that alternator ratio looks something like 3:1. Assuming a shaft speed of 2,500-2,900rpm do you need to spin the alternator that fast?

Saltfever, we use a McLaren Electronics 100 amp alternator, with a maximum continuous operating speed of 18,000 rpm. We worked with there engineers to get the pulley combo correct to optimize the unit with the least amount of drag.  Tony

Here is a link to the alternator http://www.mclarenelectronics.com/products/all/alt_wound_g_type_%28100amp%29.asp

« Last Edit: December 13, 2009, 02:14:43 AM by maguromic »
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Offline Dreamweaver

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Re: Rear Engine Modified Roadster Build
« Reply #132 on: December 13, 2009, 01:04:32 PM »
This has got to be one of the highest tech builds going on, looking forward to seeing this thing in steel and on the salt.

Lots of technology out there that is just now filtering into LSR. In my noob/no car world I see the use of aerodynamics and control surfaces the answer to letting some of these high horsepower cars use more of their available power, if they are only using half throttle you could trade off some drag.

 

Offline maguromic

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Re: Rear Engine Modified Roadster Build
« Reply #133 on: February 05, 2010, 10:54:50 AM »
It’s been a while since I had a chance to work on the project as my day job has kept me busy.  Anyway I was at (Sears Point, for us that still call it that like me) Infeneon Raceway working on the driver cell wooden mock up, when it was suggested by one of the teams there that some nice carbon tubs are available from last year’s cars.

Well it didn’t take long to convince ourselves us that this was the path of least resistance and decided to go that rout.   Thanks to O’Neil Racing the new tub will put us about 6 months ahead of schedule.  Tony


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saltfever

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Re: Rear Engine Modified Roadster Build
« Reply #134 on: February 05, 2010, 12:07:52 PM »
You got that right, Tony. It will always be Sears Point to me. Corporate PR comes and goes but the geography will never change. Glad to see you are back.  :-)