mender Posted March 9, 2018 Report Share Posted March 9, 2018 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! 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. Link to comment Share on other sites More sharing options...
zack_280 Posted March 9, 2018 Report Share Posted March 9, 2018 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. Link to comment Share on other sites More sharing options...
TiredBirds Posted March 9, 2018 Report Share Posted March 9, 2018 we added the sway bar off our WS6 parts car...almost lifted the rear wheel off the ground on hard turns... that lasted one event. Link to comment Share on other sites More sharing options...
TiredBirds Posted March 9, 2018 Report Share Posted March 9, 2018 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! 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. Still running a 305, no real need for more at this point, not until we get better as drivers. Link to comment Share on other sites More sharing options...
Administrators Bill Strong Posted March 9, 2018 Administrators Report Share Posted March 9, 2018 Worst mod on the MR2? can't think of any. Link to comment Share on other sites More sharing options...
FlorahDorah Posted March 9, 2018 Report Share Posted March 9, 2018 Most drivers at one time or another.... Link to comment Share on other sites More sharing options...
wvumtnbkr Posted March 9, 2018 Report Share Posted March 9, 2018 worst mod.... brake duct fans.... They failed after a few hours and caused some other electrical issues costing us plenty of wrench time.... Link to comment Share on other sites More sharing options...
JDChristianson Posted March 9, 2018 Report Share Posted March 9, 2018 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. Link to comment Share on other sites More sharing options...
Technical Advisory Committee NigelStu Posted March 9, 2018 Technical Advisory Committee Report Share Posted March 9, 2018 "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.... Link to comment Share on other sites More sharing options...
Ronh911 Posted March 10, 2018 Report Share Posted March 10, 2018 Installing lightweight aluminum exhaust pipe, lasted all of 30 minutes, Link to comment Share on other sites More sharing options...
Xph Posted March 11, 2018 Report Share Posted March 11, 2018 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. Link to comment Share on other sites More sharing options...
wvumtnbkr Posted March 11, 2018 Report Share Posted March 11, 2018 yep, bilge fan jobbies. Link to comment Share on other sites More sharing options...
Mopar 4 Life Posted March 12, 2018 Report Share Posted March 12, 2018 Tried an aluminum exhaust once for max weight savings. It broke in strange places and not where the welds were. Link to comment Share on other sites More sharing options...
Zauskycop Posted March 12, 2018 Report Share Posted March 12, 2018 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! Link to comment Share on other sites More sharing options...
Alchemy Autosport Posted March 12, 2018 Report Share Posted March 12, 2018 +1 on header wrapping too much of the exhaust pipe. Broke right at the end of the wrap. Link to comment Share on other sites More sharing options...
55mini Posted March 13, 2018 Report Share Posted March 13, 2018 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. Link to comment Share on other sites More sharing options...
bbaker480 Posted March 14, 2018 Report Share Posted March 14, 2018 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. Link to comment Share on other sites More sharing options...
Black Magic Posted March 14, 2018 Report Share Posted March 14, 2018 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. Link to comment Share on other sites More sharing options...
bbaker480 Posted March 14, 2018 Report Share Posted March 14, 2018 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. Link to comment Share on other sites More sharing options...
enginerd Posted March 14, 2018 Report Share Posted March 14, 2018 52 minutes ago, Black Magic said: Important details i probably left out when people asked before. Well played. Link to comment Share on other sites More sharing options...
mender Posted March 14, 2018 Author Report Share Posted March 14, 2018 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. Link to comment Share on other sites More sharing options...
Black Magic Posted March 14, 2018 Report Share Posted March 14, 2018 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.... Link to comment Share on other sites More sharing options...
Technical Advisory Committee Andrew D Johnson Posted March 14, 2018 Technical Advisory Committee Report Share Posted March 14, 2018 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. Link to comment Share on other sites More sharing options...
mender Posted March 14, 2018 Author Report Share Posted March 14, 2018 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. I quit wrapping headers 25 years ago ... Ceramic coating works much better. Link to comment Share on other sites More sharing options...
Technical Advisory Committee Andrew D Johnson Posted March 14, 2018 Technical Advisory Committee Report Share Posted March 14, 2018 Just now, mender said: I quit wrapping headers 25 years ago ... Ceramic coating works much better. I quit wrapping headers after that race I quit building headers after that race too. Link to comment Share on other sites More sharing options...
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