A bit of IMSA history came to the dyno today...come learn something inside.
05-23-2009, 09:46 PM
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A bit of IMSA history came to the dyno today...come learn something inside.
So, I've been waiting for this day for quite some time. Well, a little over a month. The owner of this car, Glenn Bunch, contacted me after my shop and I were recommended to take care of his car while being dyno'd and tuned. You see, it's not just your average, everyday, run-of-the-mill car to dyno. Oh no, this car is a rolling, fire-belching, quad-weber laden classic piece of automotive racing history.
Before I get to the pics I'm going to throw some history at you so you can fully appreciate this absolute beast of a Dodge Challenger.
In the mid-70's Glenn Bunch started having ideas of building an IMSA car to compete against the, at the time, unbeatable Corvettes and Porsches. He wanted to go head to head with Greenwood in AAGT and to do that he needed to come up with a plan. He didn't want to do it the same way everyone else was doing it though. He came up with the notion, "that power to weight ratio, frontal area and tire sizes were the key factors to a fast car". With that in mind he was looking for some sort of advantage...a custom tube chassis, big-bodied, Hemi-powered, Dodge Challenger with a custom body to house some insanely large rubber. Yea, that'll do.
With building a custom chassis he could move the engine wayyyy back, along with adding weight to the rear, he could create a tail-heavy situation...even with the added weight of the Hemi. The final answer comes in the form of a 426c.i.based Hemi, strapped to a deceivingly lite car, with all custom body work made by the owner himself. Every piece. In fact, the only....only factory "Challenger" part on this car is the roof skin. Thats it. Everything else was handcrafted fiberglass by Glenn himself to create the right amount of downforce and whatever it took to cover the tires needed to keep up with the insane power of the Porsche 935s.
Here is the very first pic of his build:
Pic of it in the suspension stages of the build:
But this didn't come without it's problems. You see, in 1978 he showed up to Road Atlanta and was told to go home because his body work was deemed illegal because the fender bulges had carried into the hood. There is some controversy to this because it was never specifically in the rule book, but he was sent home and he literally went back to the drawing board to change his car to fit the rules.
Here is the car in the paddock of Road Atlanta with the "illegal" body work:
Now over the few next years Glenn struggled with engine combination that made the power he needed, but had the right powerband, as well has having problems constantly with carb tuning coming out of corners. He was never happy with the power of the 426 and with his newly rebodied Challenger, at Mid-Ohio after a short practice session the Hemi was having issues holding oil pressure. In the next session coming into the brake zone from the main straight at 7,700rpms it decided to spin a bearing and throw a rod. In fact, the main cap was ejected from the block, bounced off the track and embedded itself into the aluminum floor of the car right under his seat! His engine troubles continued for years. Experimenting with different cranks and going from 426c.i., to 528c.i., to 572c.i. and a few in between.
The car also went through many suspension/chassis changes as well as the years passed. The leaf springs were changed to a 3 link/panhard and the chassis was getting lighter and lighter the more he tinkered with it. It went from being 3200lbs to 2750lbs to finally its current 2450lbs dry weight!
The body designs changed as well:
Before I get to the pics I'm going to throw some history at you so you can fully appreciate this absolute beast of a Dodge Challenger.
In the mid-70's Glenn Bunch started having ideas of building an IMSA car to compete against the, at the time, unbeatable Corvettes and Porsches. He wanted to go head to head with Greenwood in AAGT and to do that he needed to come up with a plan. He didn't want to do it the same way everyone else was doing it though. He came up with the notion, "that power to weight ratio, frontal area and tire sizes were the key factors to a fast car". With that in mind he was looking for some sort of advantage...a custom tube chassis, big-bodied, Hemi-powered, Dodge Challenger with a custom body to house some insanely large rubber. Yea, that'll do.
With building a custom chassis he could move the engine wayyyy back, along with adding weight to the rear, he could create a tail-heavy situation...even with the added weight of the Hemi. The final answer comes in the form of a 426c.i.based Hemi, strapped to a deceivingly lite car, with all custom body work made by the owner himself. Every piece. In fact, the only....only factory "Challenger" part on this car is the roof skin. Thats it. Everything else was handcrafted fiberglass by Glenn himself to create the right amount of downforce and whatever it took to cover the tires needed to keep up with the insane power of the Porsche 935s.
Here is the very first pic of his build:
Pic of it in the suspension stages of the build:
But this didn't come without it's problems. You see, in 1978 he showed up to Road Atlanta and was told to go home because his body work was deemed illegal because the fender bulges had carried into the hood. There is some controversy to this because it was never specifically in the rule book, but he was sent home and he literally went back to the drawing board to change his car to fit the rules.
Here is the car in the paddock of Road Atlanta with the "illegal" body work:
Now over the few next years Glenn struggled with engine combination that made the power he needed, but had the right powerband, as well has having problems constantly with carb tuning coming out of corners. He was never happy with the power of the 426 and with his newly rebodied Challenger, at Mid-Ohio after a short practice session the Hemi was having issues holding oil pressure. In the next session coming into the brake zone from the main straight at 7,700rpms it decided to spin a bearing and throw a rod. In fact, the main cap was ejected from the block, bounced off the track and embedded itself into the aluminum floor of the car right under his seat! His engine troubles continued for years. Experimenting with different cranks and going from 426c.i., to 528c.i., to 572c.i. and a few in between.
The car also went through many suspension/chassis changes as well as the years passed. The leaf springs were changed to a 3 link/panhard and the chassis was getting lighter and lighter the more he tinkered with it. It went from being 3200lbs to 2750lbs to finally its current 2450lbs dry weight!
The body designs changed as well:
Last edited by FlimFlam; 05-24-2009 at 05:30 AM.
05-23-2009, 09:46 PM
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Re: A bit of IMSA history came to the dyno today...come learn something inside.
As for when I was introduced to this car, it was at Road Atlanta in 2007 at the Walter Mitty Festival:
When I saw the car in person I had absolutely NO clue what I was looking at, but I knew it was fucking badass as a motherfucker to be blunt. I found the car in the paddock and looked it over for quite some time. I could tell it was hauling serious ass on track and the person behind the wheel wasn't treating it like your typical "vintage racer/collectible racecar". Instead they were straight up running the hell out of the car. Little did I know that the driver was the original owner/builder/IMSA driver/official badass. Now I know.
I had later seen the car at the VIR Gold Cup Vintage races and the Ultimate Track Car Challenge at VIR last year where he had engine problems both times.
Fast forward a year and a few months later and I'm on the phone with Glenn scheduling to bring me his Challenger to dyno. To say the least, I cleared my calendar. And this morning, 10am, the Challenger rolled into my shop. It barely fit on the dyno. It's...wide. For the next 4hrs Glenn dialed in his 4, 58mm Webers to get rid of some low RPM bogging and a little bit of leanness in the upper RPMS. His final numbers were 670rwhp and 703rwtq. Again, remember that this car weighs 2450lbs and has about 16" of tire under it. It's the definition of ridiculous.
Anywho, onto the pics from today:
When I saw the car in person I had absolutely NO clue what I was looking at, but I knew it was fucking badass as a motherfucker to be blunt. I found the car in the paddock and looked it over for quite some time. I could tell it was hauling serious ass on track and the person behind the wheel wasn't treating it like your typical "vintage racer/collectible racecar". Instead they were straight up running the hell out of the car. Little did I know that the driver was the original owner/builder/IMSA driver/official badass. Now I know.
I had later seen the car at the VIR Gold Cup Vintage races and the Ultimate Track Car Challenge at VIR last year where he had engine problems both times.
Fast forward a year and a few months later and I'm on the phone with Glenn scheduling to bring me his Challenger to dyno. To say the least, I cleared my calendar. And this morning, 10am, the Challenger rolled into my shop. It barely fit on the dyno. It's...wide. For the next 4hrs Glenn dialed in his 4, 58mm Webers to get rid of some low RPM bogging and a little bit of leanness in the upper RPMS. His final numbers were 670rwhp and 703rwtq. Again, remember that this car weighs 2450lbs and has about 16" of tire under it. It's the definition of ridiculous.
Anywho, onto the pics from today:
Last edited by FlimFlam; 05-24-2009 at 05:31 AM.
05-23-2009, 09:47 PM
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Re: A bit of IMSA history came to the dyno today...come learn something inside.
DOPE STATUS!!!
There is a LOT more to this story, but I just can't put it all into this thread. And I know that 98% of you are just going to look at the pictures anyways, so I won't waste my time. You can go to www.glennbunch.com to read the whole story, see more pics, and watch videos of the car on track.
Hope you learned something.
05-23-2009, 09:56 PM
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Re: A bit of IMSA history came to the dyno today...come learn something inside.
