This is a Question for info only....(I have never and probably never will compete in Drag Racing). Can someone explain the advantage of Swing Axle rear suspension over IRS when Drag Racing. I would have thought that IRS would work better as it tends to keep the rear wheels in a more vertical plane compared to Swing axle which tends to go to positive camber. I have noticed on this Forum that most/all of the top VW drag cars use "Swing Axle". Correct me if I am wrong but I think I read that Rod Penrose used a Kombi box modified to swing axle in his previous racecar. Also whilst I am on the subject ( I have an interest in rear suspension design for Drag Cars) can someone explain what modifications are/can be made to VW rear suspension to improve traction i.e. are Ladder Bars/Four Links desireable /practical? Lots of questions I know but as "they" say if you don't ask!!!
thanks ,
Glenn

Swing axle is lighter (no need for trailing arms) and potentially stronger.

Definatly swing is better for drags for strength and weight.

IRS for cornering... but if your willing to upgrade to kombie or porsche 930 cv's then IRS is just as good if not better. This is due to weight transfer to the rear end during the launch, and swing axels tucking in under the guard as more weight moves backwards. Especially true if you expect to lift the front wheels on launches.

In the end what this means is tha both are good and it comes back to budget. There are a lot of successful cars out there that run swing and irs.

The http://www.shoptalkforums.com  suspension threads are usefull for getting more info.

I have always used IRS cars for dragracing, but in the end,
yes, swingaxle is lighter, and probably easyer to make strong.
I went to great lengths with my tube car to keep the tyre square by using IRS and De-deon,
but in the end the swingaxle cars, with a ladder bar was better despite the toe and camber change.
The standard rear suspension (either type) is so close to correct for dragracing it's almost laughable.
Other than correct alignment and strength upgrades,
only a heavyer tortion bar may be required depending on the car's weight or torque output.
There are many exceptions and additions dependant on idividual applications though.

Thanks for the replies....I now understand a little more and... yes Craig Torrens that engine is coming!!!!

IRS is better when you lose control of the tail and hit gutters/drains/rocks/armco - less chance of the driveshaft smashing the diff. And IRS is easier to change boxes

Damon Harmon (spelling) the PRA prostock VW champion in the US uses IRS, but most every one else uses swing axle, so they both work very well. Swing costs less to make strong and is a simplear design. IRS is easier to change parts if they brake, like gearbox and axles.

Hermann.