Page 1 of 1

Stinger Test

Posted: Thu Jul 23, 2020 6:37 pm
by FJCamper
Image

The RetroRacing Super Beetle as most competitors see it, all aft-end. Standard stinger on duty.

The drag race crowd doesn't have the problem of some Rice Grinder trying to draft you at a foot off your tail. Racing LeMons, we've lost a few stingers over the years. And length is not the only problem. Even at the track, a stinger makes us among the loudest cars out there, and we're above some decible limits.

Rather than go by theory, we decided to modify a stinger or two, trek to the track in our HSR Ghia,, and see what happens. By the book, if you cut down a stinger on a 4-into-1 collector, you loose low-end torque. Wide open throttle power is largely unaffected. So we cut a stock 17" EMPI stinger to about half length and bolted a short (3") motorcycle baffle into it. The motorcycle baffle had a perforated center pipe in it,

The engine was a high-winding 1915, 42x37.5 valves, 1.25 rockers, Engle W140 cam, dual Weber 48IDF's, on 38mm venturis. This was our Bonneville engine from last year, the compression dropped from 11:1 to 10.3:1 for road racing.

With the short stinger, we had no power above 3000rpm.

Fitted with the standard length stinger and a standard EMPI baffle (but no fiberglass batting) the Ghia was soon flying as per normal, 6500 in 3rd . The Grand Prix track is too short for our 3.88 final drive.) There was no reason to make more laps with an unbaffled stinger.

FJC

Re: Stinger Test

Posted: Fri Jul 24, 2020 4:10 pm
by GS guy
FJ, your post reminded me of a slick looking Sun Bug Beetle I used to see daily back in my HS days (mid/late 70's). What I found very unique was the exhaust - this was largely pre QP days, so most Beetle performance exhausts ended in a glass-pack muffler of some sort, or stinger. This particular Beetle, however, had twin stingers coming off the collector, each one pointing off to the side of the car and angled slightly down. Probably baffled as it wasn't too loud, although it probably had an otherwise mostly stock engine (maybe a Bugspray under the hood?). Never seen another exhaust like that one, of all the hundreds of different manufacturers and designs produced over the decades. Having a (or 2?) stingers come off your exhaust mostly parallel to the lower support bar might alleviate the "shunting" problem and who knows - open up a few more ponies?
Jeff

Re: Stinger Test

Posted: Tue Jul 28, 2020 7:49 pm
by GS guy
Maybe something like this?

Re: Stinger Test

Posted: Thu Aug 06, 2020 12:15 am
by chuckput
Maybe use something like this off road race header

VWRaceHeaders.jpg

Re: Stinger Test

Posted: Thu Aug 06, 2020 9:31 pm
by sideshow
With no rear apron, I all so vote for the over the top stinger...more ground clearance

Re: Stinger Test

Posted: Thu Sep 17, 2020 7:09 am
by 4agedub
I have never had luck with the stinger tail piece and frankly I cannot see why you would want to use it. Back to back runs on a loading dyno the stinger always made less power than a silenced system.

Here's what we did to get some length on the exhaust without protruding too far behind the car.
The header is 1 7/8" and the rest of the system is 3"
118893586_10158861471037456_5035567273896838945_n.jpg
118880981_10158861471172456_486498418338908286_n.jpg
118599955_10158823918962456_1451553257387958836_n.jpg

Re: Stinger Test

Posted: Thu Sep 17, 2020 9:44 am
by Ol'fogasaurus
Pile, as I am sure you already know that this is an age old problem/discussion; e.g., length vs. bends tube size and, apparently, exit size and shape may come into play also. If you do a search on this you get mostly motorcycle info which is not that bad when compared to car exhaust length and bends.

Here is a bunch of info that may or may not help: https://www.bing.com/search?q=calculati ... fdf7c47d71

Its been a long time since I got into this but as I remember there has been a lot of calculations and time in a test facility per car on this. Header length for sure but the rest of the tail pipe has a lot to do with things. As I remember torque can change as well as the top end abilities.

As I remember the exhaust pulses from each cylinder does have an effect and the back pulse going up to the valve then back out pulling the following exhausts is important (or at least was) in the calculations for exhaust length.

The old trumpet shaped/flared exhaust tips came about from these design studies years ago then slowly faded out as ignorance set back in (I don't know if they really helped but the concept did come out of studies anyway.

As you know 4 into 1 works better on a "dub" than 2 two tubed shaped headers and a bit quieter also.

Sorry about butting in but I thought this might help some.

Lee