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Worst mods


mender
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How about worst mods made that bit the perpetrators when they attempted to pull a fast one? It even happens in chump. I know: shocking but true! :o

 

1. Back in the early chump days a team could do a family engine swap for free. The example was a 305 to 350 swap. I know of a team that appeared to follow that rule but instead of using a stock block, they installed the longer stroke crank of the bigger engine and cut the pistons to make flat tops and raise the compression. The bite: the engine failed because of too low octane for the compression,  aggressive tune and thin piston tops. Kind of appropriate.;)

 

2. Same team then replaced that with another engine that would have been legal but now due to a change in the engine swap rule would be assigned $50 as a net zero swap. Better and even bigger engine, very reliable and cheap. But the team rebuilt the engine with high compression non-stock pistons, added some aftermarket rocker arms and an adjustable fuel pressure regulator to correct the fuel curve, took off the better heads and intake that came with the new engine and swapped on the old heads and intake and tried to pass it off as stock so they would have nothing added to their TCV. The result was an engine that, despite all the extra cost, work, and illegal parts, made about the same whp as the stock legal engine swap would have and then failed in the first weekend. 

 

Crime doesn't pay and in this case neither did cheating. :P

Edited by mender
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I know a team that built a 2.7L stroker E30 using 2.7L crank, forged rods, high compression pistons, and slightly aggressive street cam and didn't claim any of it.  It was pretty fast for ~1.5 hours before it blew the eff up.  That's the only time that team has ever had catastrophic engine failure. 

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3 hours ago, mender said:

How about worst mods made that bit the perpetrators when they attempted to pull a fast one? It even happens in chump. I know: shocking but true! :o

 

1. Back in the early chump days a team could do a family engine swap for free. The example was a 305 to 350 swap. I know of a team that appeared to follow that rule but instead of using a stock block, they installed the longer stroke crank of the bigger engine and cut the pistons to make flat tops and raise the compression. The bite: the engine failed because of too low octane for the compression,  aggressive tune and thin piston tops. Kind of appropriate.;)

 

2. Same team then replaced that with another engine that would have been legal but now due to a change in the engine swap rule would be assigned $50 as a net zero swap. Better and even bigger engine, very reliable and cheap. But the team rebuilt the engine with high compression non-stock pistons, added some aftermarket rocker arms and an adjustable fuel pressure regulator to correct the fuel curve, took off the better heads and intake that came with the new engine and swapped on the old heads and intake and tried to pass it off as stock so they would have nothing added to their TCV. The result was an engine that, despite all the extra cost, work, and illegal parts, made about the same whp as the stock legal engine swap would have and then failed in the first weekend. 

 

Crime doesn't pay and in this case neither did cheating. :P

Still running a 305, no real need for more at this point, not until we get better as drivers.

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  • Technical Advisory Committee

"De-fogging" hose curved around passenger side A-pillar.   did nothing to keep windshield clear, but did an excellent job of directing water from outside the car onto what would normally be the dry side of the driver....

 

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On 3/9/2018 at 4:04 PM, wvumtnbkr said:

worst mod....

 

brake duct fans....

 

They failed after a few hours and caused some other electrical issues costing us plenty of wrench time....

 

Any particulars, just the bilge fan jobbies?  They were on my todo list over winter but didnt get there.

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On 3/9/2018 at 4:35 PM, NigelStu said:

"De-fogging" hose curved around passenger side A-pillar.   did nothing to keep windshield clear, but did an excellent job of directing water from outside the car onto what would normally be the dry side of the driver....

 

As the driver who couldn't see the track...I agree with this!

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On 3/9/2018 at 4:33 PM, JDChristianson said:

Wrapping too much of the exhaust. Pipe gets to hot, does weird metal stuff and breaks.    Then shoots hot exhaust on pinion seal.  Pinion seal very unhappy and let's all the lube out.   

Hey at least when the diff went we were able to start the grass on fire at the edge of the track! Being parked at night and watching the fire glow.

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On 3/11/2018 at 7:39 PM, wvumtnbkr said:

yep, bilge fan jobbies.

I think we failed twice on this one, the first issue being that the fans were wired into the fuel pump circuit, and the second being that no screen was installed on the duct.  Once they loaded up with rubber and the fans locked up the motors died and shorted both fans to ground, which in turn blew the fuse for the fuel pumps.  

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16 minutes ago, bbaker480 said:

I think we failed twice on this one, the first issue being that the fans were wired into the fuel pump circuit, and the second being that no screen was installed on the duct.  Once they loaded up with rubber and the fans locked up the motors died and shorted both fans to ground, which in turn blew the fuse for the fuel pumps.  

 

For anyone else running fans (i do), you know us nascar guys wire each fan to its own self resetting relay after the switch....

 

You also need 1/8 or more fan to housing clearance, and or run screen mesh over the inlet. 

 

Important details i probably left out when people asked before. 

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32 minutes ago, Black Magic said:

 

For anyone else running fans (i do), you know us nascar guys wire each fan to its own self resetting relay after the switch....

 

You also need 1/8 or more fan to housing clearance, and or run screen mesh over the inlet. 

 

Important details i probably left out when people asked before. 

The circuit breaker/relay makes sense but are you trimming the blades of the fans?  I honestly don't know that the fans helped much but then again we only got to test with them for an hour or so before they cost us a top 5 finish.  

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52 minutes ago, Black Magic said:

 

For anyone else running fans (i do), you know us nascar guys wire each fan to its own self resetting relay after the switch....

 

You also need 1/8 or more fan to housing clearance, and or run screen mesh over the inlet. 

 

Important details i probably left out when people asked before. 

Also, verify the polarity of your fan wiring, especially after a repair by another shop ...

 

We had an engine fire after light contact with a wall (ps fluid sprayed onto the headers) and didn't have time to take the car across three provinces for repair so left it with a local NASCAR shop. We had major issues with the wiring at the next event; the shop had wired the new rad fan backwards and it was being driven hard enough by the air flowing through the rad at 150 mph that it was generating power and shorting out the circuit. It was also acting as a restriction so the engine was heating up. 

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34 minutes ago, bbaker480 said:

The circuit breaker/relay makes sense but are you trimming the blades of the fans?  I honestly don't know that the fans helped much but then again we only got to test with them for an hour or so before they cost us a top 5 finish.  

 

Some fans come with more radial clearance. I have also see the blade area of the fan housing cut away, and a larger od tube slipped over the original housing. 

 

Done right with big enough power (like 5 amp draw each) they were very effective on the neon. Had one side taken out in a wreck, that side went metal to metal in the next 5 hrs. Other side had 3/4 pad left. 

 

Pad life is linear with temp, until a point where it goes exponential. If the fans pull you below that critical temp, they are a lifesaver. If they only move you down the linear part of the curve, you only get a small gain. Also bear in mind, more airflow only helps if the flow path isnt poop, so most cars 3/4" wide rotors with 1/4 of width for rotor "vanes" isn't going to transfer much heat. Nascar rotors are 1.25" thick, and a finger will fit in the vane slot....

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  • Technical Advisory Committee
On 3/12/2018 at 4:37 PM, Alchemy Autosport said:

+1 on header wrapping too much of the exhaust pipe.  Broke right at the end of the wrap.

 

 

 

We built our own header once and wrapped it. Three of the runners broke and one vacated completely. It broke an hour into the race, but we still finished 3rd. 

 

post-487-0-75090900-1341540787_thumb.jpg

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4 minutes ago, red0 said:

 

We built our own header once and wrapped it. Three of the runners broke and one vacated completely. It broke an hour into the race, but we still finished 3rd. 

 

post-487-0-75090900-1341540787_thumb.jpg

I quit wrapping headers 25 years ago ...

 

Ceramic coating works much better.

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