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KyAllroad (Jeremy) (Forum Supporter)
KyAllroad (Jeremy) (Forum Supporter) UltimaDork
5/12/20 2:08 p.m.

In reply to wheels777 :

I'm honestly curious.  I can see why they would do poorly on the 60'.  I understand why any time lost in a drag race is gonna be bad for the ET.  I don't understand why the trap speed would be higher.

 

And the reason for doing all this is "because we can"?

engiekev
engiekev Reader
5/12/20 2:10 p.m.

Kiggly racing is hitting 1.25s 60ft with a fwd Pymouth Laser, but that car has seen decades of development:

https://www.facebook.com/KigglyRacing/

06HHR (Forum Supporter)
06HHR (Forum Supporter) GRM+ Memberand Dork
5/12/20 2:31 p.m.

In reply to KyAllroad (Jeremy) (Forum Supporter) :

My WAG is that once you don't have to deal with weight transfer after the launch anymore having the engine and transmission over the drive wheels gives you more traction and you don't have to add as much aero (wings) to keep the drive wheels on the track so less corresponding drag. So, you can put more power to the ground at top end with less downforce and drag from big wings due to theoretically better mechanical grip at the "big end" of the track.  I'm not the expert tho..

wheels777
wheels777 SuperDork
5/12/20 3:07 p.m.
KyAllroad (Jeremy) (Forum Supporter) said:

In reply to wheels777 :

I'm honestly curious.  I can see why they would do poorly on the 60'.  I understand why any time lost in a drag race is gonna be bad for the ET.  I don't understand why the trap speed would be higher.

 

And the reason for doing all this is "because we can"?

FWD have less parasitic drivetrain loss and it allows the added HP to accelerate harder in high gear. 

wheels777
wheels777 SuperDork
5/12/20 3:15 p.m.
engiekev said:

Kiggly racing is hitting 1.25s 60ft with a fwd Pymouth Laser, but that car has seen decades of development:

https://www.facebook.com/KigglyRacing/

Perfect example. A RWD car would be running 1.11 and quicker 60' times to run 7 second quarter mile times.  A 1.25 is on par for RWD car running 8.99-9.00 quarter mile times. Kiggly's 60' is incredible for a FWD and  a slug for a RWD with equivalent quarter mile ET. Thanks for sharing that. It illustrates the challenge for the platform. 

wheels777
wheels777 SuperDork
5/12/20 3:16 p.m.
06HHR (Forum Supporter) said:

In reply to KyAllroad (Jeremy) (Forum Supporter) :

My WAG is that once you don't have to deal with weight transfer after the launch anymore having the engine and transmission over the drive wheels gives you more traction and you don't have to add as much aero (wings) to keep the drive wheels on the track so less corresponding drag. So, you can put more power to the ground at top end with less downforce and drag from big wings due to theoretically better mechanical grip at the "big end" of the track.  I'm not the expert tho..

It's reduced drivetrain loss as noted above. 

Boost_Crazy
Boost_Crazy HalfDork
5/12/20 3:26 p.m.

I’m very interested in this project. Since this chassis has seen a wide range of experience with drag racing- in FWD, RWD, and AWD form, it will be neat to see how this build compares. The build looks terrific. I also want to point out, when you are finished with this build- there looks to be plenty of room to add an identical power train in the rear.

evildky
evildky SuperDork
5/12/20 3:34 p.m.

When I thought the Nelson clan couldn't surprise me anymore. Holy cow!

wheels777
wheels777 SuperDork
5/12/20 3:35 p.m.
Boost_Crazy said:

I’m very interested in this project. Since this chassis has seen a wide range of experience with drag racing- in FWD, RWD, and AWD form, it will be neat to see how this build compares. The build looks terrific. I also want to point out, when you are finished with this build- there looks to be plenty of room to add an identical power train in the rear.

A future owner would be more than welcome to add the next engine. We have our immediate goals with the SBE LS-4 engine. It is being built for the $2000 Challenge and the LS-4 Challenge. After the $2000 Challenge we may convert to Methanol, add an S480 and chase a number. But we have no desire to add another engine. We are hearing that there are some folks who hate money more then we love the car. Just sayin'. 

wheels777
wheels777 SuperDork
5/12/20 3:40 p.m.
evildky said:

When I thought the Nelson clan couldn't surprise me anymore. Holy cow!

Hold my beer. You're gonna fall over in  2021

wheels777
wheels777 SuperDork
5/12/20 4:30 p.m.

Example

https://youtu.be/otf0X8PZmp8

 

jump forward to 1:05 into the video 

engiekev
engiekev Reader
5/12/20 5:08 p.m.
wheels777 said:
engiekev said:

Kiggly racing is hitting 1.25s 60ft with a fwd Pymouth Laser, but that car has seen decades of development:

https://www.facebook.com/KigglyRacing/

Perfect example. A RWD car would be running 1.11 and quicker 60' times to run 7 second quarter mile times.  A 1.25 is on par for RWD car running 8.99-9.00 quarter mile times. Kiggly's 60' is incredible for a FWD and  a slug for a RWD with equivalent quarter mile ET. Thanks for sharing that. It illustrates the challenge for the platform. 

If you've seen Kiggly's car in person, its a wonder!  He is a chief engineer at Pratt & Miller, so he kinda knows his stuff. He's done a lot to advance the 1G Auto platform for drag racing.

The FWD DSM platform is not bad really, you can get them quite light! Any estimates on the final weight? If you can break into the 9s at the challenge that will be legendary!

KyAllroad (Jeremy) (Forum Supporter)
KyAllroad (Jeremy) (Forum Supporter) UltimaDork
5/12/20 5:29 p.m.

So ideally something like a Fiero would give you the best of both worlds?

wheels777
wheels777 SuperDork
5/12/20 8:47 p.m.
KyAllroad (Jeremy) (Forum Supporter) said:

So ideally something like a Fiero would give you the best of both worlds?

If you want a wheelie mobile yes. If you want max performance no. Engine rotation is the wrong direction to be good for a high speed and high power. If your looking for 10 11 12 yes. But I would shy away if it will be faster then 10.0. Just my opinion. 

KyAllroad (Jeremy) (Forum Supporter)
KyAllroad (Jeremy) (Forum Supporter) UltimaDork
5/12/20 11:29 p.m.

In reply to wheels777 :

Engine rotation?  I'm so lost, I understand that drag racing is not my forte'.  I'd even say that I'm wildly ignorant of the subject but always willing to learn.   How is engine rotation relevant?

wheels777
wheels777 SuperDork
5/13/20 5:26 a.m.
KyAllroad (Jeremy) (Forum Supporter) said:

In reply to wheels777 :

Engine rotation?  I'm so lost, I understand that drag racing is not my forte'.  I'd even say that I'm wildly ignorant of the subject but always willing to learn.   How is engine rotation relevant?

FWD and RWD cars pitch up during acceleration. That makes the front end lighter and the rear heavier.  Hence the challenge for maxing the acceleration rate off the line and the RWD advantage.
If you place the engine in the back the front end is lighter.  If you trans mount your engine it will pitch the chassis up do to engine torque.

So, now to your question...if your car is pitching up from acceleration and the engine torque is compounding that rotation... I would be very leary about building an all out effort with the Fiero/LS-4 combo. To run 9s you're going to be rolling over 134 mph and the air could also be potentially lifting the front end making the front end even lighter. You may have something you can get down the track with but I would think time will not be in your favor and it will get out of shape and try to swap ends at some point (fighter jet).

Consider this, All Super cars use longitudinal mounting and that eliminates the rotational input relative to the car's pitch rotation.  

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
5/13/20 7:45 a.m.

In reply to wheels777 :

I'm confused, because all FWD transverse cars (to my knowledge) rotate the engine in the same direction as the wheels in forward gears. Early hondas are 'reverse' rotation engines, but that is because they are on the other side of the car and gearbox. 

An easy way to think about what you are describing is a motorcycle with a chain. To accelerate, the wheel is being pulled forward by the engine, therefore the tension is on the top of the chain. that same tension pulls the engine backward - or makes it tend to pitch up like you say. 

What im confused about is how a honda wouldn't also do that. 

Edit, if the chain is really long, then the pitching of the engine has less effect on the pitch of the car. If the chain is really short (like transverse midship RWD), then there would be a large effect. 

wheels777
wheels777 SuperDork
5/13/20 8:28 a.m.

In reply to Robbie (Forum Supporter) :

The original statement noted IIRC because I was not sure of the manufacturer. I revised to eliminate that part of the discussion. I was rushing to get to work and wanted to make a quick reply. Regardless, the issue is the torque induced pitch rotation. The goal was to offer info to make sure someone did not build something that could have unintended consequences. 

Pete Gossett (Forum Supporter)
Pete Gossett (Forum Supporter) GRM+ Memberand MegaDork
5/13/20 8:44 a.m.

In reply to Robbie (Forum Supporter) :

FYI stock 1 & 2G DSMs rotate the engine in the opposite direction as the wheels(when going forward). There's a prop shaft inside the trans that reverses direction & powers the center diff. 

wheels777
wheels777 SuperDork
5/13/20 8:53 a.m.
Pete Gossett (Forum Supporter) said:

In reply to Robbie (Forum Supporter) :

FYI stock 1 & 2G DSMs rotate the engine in the opposite direction as the wheels(when going forward). There's a prop shaft inside the trans that reverses direction & powers the center diff. 

Thanks. I know there is a manufacturer that spun the engine in a way that it countered the pitch rotation associated with accelerating. Unfortunately I errantly said IIRC Honda when I hastily replied earlier today. Most (IIRC all but 1) manufacturers are set up in a manner that causes the two to compound, not counter, the pitch.  The engine rotation the same as the wheels rotation will counter the pitch tendencies. 

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) Dork
5/13/20 9:41 a.m.

Interesting discussion. I think KY's "all things being equal" is the hard part of the calcs, rarely this is true. As Andy stated  previously low 1.x 60's are possible RWD without too much hassle, and even some of the quickest FWD can only get to mid 1.4x, there can be an even bigger difference at the 330 as the FWD tries to spin the tires again. Most FWD are going to be geared to top end so running same ET the FWD will be pulling 10-20mph more trap speed, as the average hp put down may be the same just the FWD has to put more down later to catch up. 

I have been chasing a 1.4x 60' in my personal car for a while, best is 1.51 and it's taken awhile to get there (and a trail of broken things!)

PS email me at kandpperformance at gmail dot com for those tires and talk about some FWD can't figure out where PM went

wheels777
wheels777 SuperDork
5/13/20 10:39 a.m.

In reply to Paul_VR6 (Forum Supporter) :

Sent

wheels777
wheels777 SuperDork
5/15/20 4:47 a.m.
engiekev said:
wheels777 said:
engiekev said:

Kiggly racing is hitting 1.25s 60ft with a fwd Pymouth Laser, but that car has seen decades of development:

https://www.facebook.com/KigglyRacing/

Perfect example. A RWD car would be running 1.11 and quicker 60' times to run 7 second quarter mile times.  A 1.25 is on par for RWD car running 8.99-9.00 quarter mile times. Kiggly's 60' is incredible for a FWD and  a slug for a RWD with equivalent quarter mile ET. Thanks for sharing that. It illustrates the challenge for the platform. 

If you've seen Kiggly's car in person, its a wonder!  He is a chief engineer at Pratt & Miller, so he kinda knows his stuff. He's done a lot to advance the 1G Auto platform for drag racing.

The FWD DSM platform is not bad really, you can get them quite light! Any estimates on the final weight? If you can break into the 9s at the challenge that will be legendary!

Max effort on reducing weight. Max effort on a SBE LS with a tractor trailer turbo. Y'all can start a pool on the ET. 

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) Dork
5/15/20 8:20 a.m.

Post the turbo specs and I'm in for some wagering!

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
5/15/20 8:29 a.m.
Pete Gossett (Forum Supporter) said:

In reply to Robbie (Forum Supporter) :

FYI stock 1 & 2G DSMs rotate the engine in the opposite direction as the wheels(when going forward). There's a prop shaft inside the trans that reverses direction & powers the center diff. 

Mind = blown

thank you!

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