Topics

1

Front Engine Dragsters / FED bounce problem.

« on: June 20, 2020, 07:15:28 AM »

I have a 225 inch FED runs 4.90-5.0X and I am having a problem with it. Data logger is showing some bounce / tire spin down rack. Last race I took the wheelie bar off and weight out of nose to be able to run index in high altitude bad air.  I THINK I know what the problem is but want some input on how to resolve it. Mind you it is not bad but I want this car to get down any track under all conditions as close to perfect as possible.
Last week in final round saw a video that kind of affirms my thoughts. The car took off at the hit and pulled front wheels up about 8 inches and carried them out about 60 foot and then set them down nice and smooth. That is more than normal but no big deal. What I saw that was interesting is a lot of chassis flex in the middle and what I think is happening is with the long car it is flexing and causing bounce down track.  I understand some of that flex helps it hook but I think it is too much here.

I THINK stiffening up the chassis will help it hook better and smoother in the shut down area to. Several tracks we run at is rough in the shut down and it will get my car bouncing. I have also done a lot with tires and tire pressure but this is more than tires now.

My question is how can I test and verify my thinking on stiffening the chassis? Was thinking about tying the chassis with cable under tension to see if it helps and verify it is right direction to go. Something where it attaches in the front and back and goes over middle bar on top to limit downward flex. Then if it works could go in and add more bars to stiffen chassis. I want to do it right but want to verify it is heading in right direction and not making it worse before I do a bunch of major chassis changes.

2

Front Engine Dragsters / Rear End Coupler question

« on: June 04, 2019, 08:18:37 PM »

I have a Front Engine dragster with long tail shaft powerglide. Last year I had a wooden dowel in the yoke to keep the yoke to the correct depth in the pinion nut. That was not a good solution because you have to pull motor out to change transmission or converter. With the dowel in there you can not slide the yoke forward in the transmission so that means motor and midplate have to come out.

 So this year I put two slip collars on the yoke to hold it to correct depth but it has damaged the transmission seal. Loosen the slip collars, slide yoke up in transmission then you can lift transmission out the top.

So is there any good solutions that can make it easy to remove transmission and will not hurt the seal?

A friend told me someone used to make a pinion nut for coupler that had a snap ring type deal to hold the coupler in place while running. Then to remove transmission take out snap ring, push yoke forward and then you can easily take out tranny.  I have not been able to find such animal?

Mark Williams and Strange both have a quick connect yoke pinion deal but they both said the ONLY work on SHORTY transmissions.  Mark Williams said my only options are put a dowel in the yoke or change transmission to a shorty, new planitaries and then use their funny car drive shaft. That would make it fairly easy to remove transmission but would cost about $2000 and would take a lot of time. Plus I would have to fabricate a large two piece drive shaft cover over it.

3

Spud Miller's Cave / Got a problem. Probably fuel supply issue.

« on: March 20, 2017, 06:10:37 PM »

I have Enderle hat on 760 HP SBC I had been making changes to try to get it to footbrake with little success. Now car has developed a bad problem and will not come up on converter. The data logger is showing fuel pump pressure drops like a rock, all O2 sensors read lean and car just lays over.
My first thought was loose fuel line and dirty filters causing pump to suck air and not fuel. Drained fuel cell, checked and cleaned filters and checked all fittings (they were tight). Fuel filters had a few little bit of trash but it was not much and filter was not clogged. Nothing more than I consider normal.
I checked the belt and the pulleys are good. The nozzles are clean and flowing and all O2 on all 8 cylinders are consistent so it is not a clogged nozzle.

I looked in the fuel cell for paper or plastic or anything that could float around and block outlet. Nothing, yet it sounds to me like it is a fuel supply problem. Car has been running very good with same system for several years. I do see a few things I could improve to make system better but it was working good before and I need to fix the issue here.  Most of the hoses are one year old and in good shape.

I will probably put my old tune up back in it and I have a new pump that I may try but I seriously doubt that is the issue. It is acting like it is starving for fuel and sucking air.  Note I am not that far off of old tune up now and it should be way fatter. Basically I am right now one size smaller nozzles and way smaller main so it should if anything be very fat right now but it is not and in my opinion it is somehow running out of fuel.

I have two large Summit stainless filter elements that go into a tee fitting and one -10 line to bottom of pump. No sharp turns or anything like that. Returns go into top of cell near the back. I am thinking of making a manifold to return the fuel back into inlet line near pump to reduce aeration of fuel. I think it would also help to keep inlet fuel flowing and pump covered with fuel. Now I found two larger filters and will probably get them and put them on, anything I can do to increase flow and lower restriction should help but the current filters are not the problem as they have been working well and were clean.

It is not ignition as logger is not showing any missing etc.

Any suggestions? Hope I gave you enough information to give me a direction to look. Thanks,

4

Front Engine Dragsters / Some basic simple questions

« on: March 12, 2017, 07:23:10 AM »

Okay I am thinking of getting a 225 inch front engine dragster. My questions are.
1. How do you set it up so it goes straight when front wheels are up?
2. How do you limit wheelies? Or is that even an issue with 225 inch car?
3. Any other tips for setting it up so it leaves hard and straight?

While I think I may know the answers I want to verify with people who have been there done that. Thanks,

5

Spud Miller's Cave / Footbraking Enderle hat SBC

« on: February 04, 2017, 06:23:35 PM »

I have some questions and I think I am on the right track but since it is Winter and I can not verify it on the track stuck with bench racing.

On my Enderle hat injection works great on the trans brake with 4400 RPM chip in two step. My problem was in footbraking it for No Box classes.
I need to raise the RPM up around 2400-2800 to get good reaction times but when I do it will stumble and flat fall on its face. SBC 760 Hp Enderle hat with .038 nozzles and 60 PSI fuel pressure at finish line. What I did was lowered nozzles size to .034  and it should raise finish line fuel pressure to around 100 PSI. This is with Enderle 80-A1 pump flowed at 6.9.

I also added a small shim to the idle return but did not want to do too much there.  My data logger is reading zero at low RPM.

I believe what was happening was the fuel pressure was too low at the the hit causing the stumble. I believe the smaller nozzles will put out same peak power but at higher pressure and better fuel control at the hit with less stumble.

1. Is my thinking right there?

2. Is there anything else to do to help low RPM stumble?

3. What would be right size nozzles for foot braking a 760 HP SBC?  Not hard to get it tuned perfect on a dyno or at the finish line but a little trickier for foot braking.

6

Spud Miller's Cave / DSR, Enderle, waterman or Aeromotive pump?

« on: November 22, 2015, 05:30:55 PM »

I currently have an Enderle 80A-1 pump and going to A) rebuild it or B) Buy a new pump and keep this one as a spare. Note, I also have a very good 80A but it is not the newer -1 so it does not rotate and can not fit in my chassis. May sell it or trade it off for something else.
My questions are:
1.  What is the difference on durability of them?
2. How hard are they to rebuild?
3. How much do they cost to rebuild?

On the surface the DSR pump looks interesting as it appears to be similar to blower type or oil pump and it would seem to me that design would last well. No vanes or anything like to wear and fail just two gears that pump. What ever I do it has to be fairly small and must rotate to clear the chassis. My current pump is 7 GPM but I could run anything from 5.5 to 7.5 prefer to be on larger side to be safe. Thanks in advance.