I keep coming back to this.... I have to add a long-tail if for no other reason to fulfill my Group 5 / Canam fantasies. I think I can tackle it with one piece of aluminum and use it as a home for a rear diffuser too. My wing plate design should make it pretty easy to attach. What ideas do you all have?
In reply to Box4VIR :
I think your idea is on the right track. I would consider cutting the wing uprights making extensions that move the wing uprights back above the long tail 12" or so back.
I like this modern all black 935 look from Khyzyl Saleem. But narrower to keep your rear fenders.
As the proud new owner of a 986, this is a dangerous thread.
Box4VIR said:What's the overunder of these numbers being ok with the corner workers. We'll find out in two weeks!
I'm betting they'll be fine but you could always email Jeff Hall and cc Cobetto. Their contact info is here: https://nasaracing.net/contact-us/
Did you de-skin the factory body panels and rivet the CF onto the their guts or just build up all new attachment flanges? Some of them look like they overlay the factory panels and I can't figure out how that cuts weight.
Also: what's your current curb weight?
In reply to OHSCrifle :
The factory panels are completely gone (not just the skins). Places that really needed metal support, like the doors, headlight mounts, etc had aluminum structures made to replace the steel. In some cases the new carbon panels are bolted on the same way the factory panels bolt on, in other cases I had to use support rods to hold the carbon in place. There is no longer any steel panels on the car, the steel chassis itself has also been heavily cut away, the rear is basically the frame rails and a cage. This weekend at the track it weighed in at 2,612lbs, about a hundred pounds lighter than stock despite the twin turbo v8, full cage, 17" increase in width, fire suppression system, etc etc. That being said the carbon body only ended up saving 90lbs :( but thats compared to the stripped body that was on it already.
First event of the season went..ok. Pulled like crazy and all in all felt great but a improperly bleed coolant system caused a hiccup (didn't overheat just puked coolant) in the first season and then a fuse took me out of another session but otherwise it ran well...shocking. Fitting on the trailer though is rough. It's 80"s wide and an inch narrower than the trailer. Very tight squeeze
next up, crank up the boost!
Glad nothing seems particularly hurt. I heard mention of head gasket and feared the worst.
In reply to infernosg :
I thought it was a head gasket. Turns out it was an airpocket in my coolant system due to a poorly designed (by me) coolant circuit. I pulled a bunch of air out and changed up the design. All good, whew!
Any twin charger experts here...sigh.
Oh no.... what happened?
In reply to jfryjfry :
Haha, nothing. Just going back down the rabbit hole. I'm going to add a supercharger and go twin charged.
here's the plan. The supercharger is a twin scroll making 30psi on a 2L. it'll produce around 15psi on my motor I'll run another 12psi off of the turbos to get around 35psi (boost compounds between the two). I'll run the plumping from the turbos to the supercharger to an intercooler and then to a BOV. I might need a BOV between the turbos and supercharger. Any feedback on the design? The idea is to improve low end performance.
I have been involved with doing it on a Ford GT many times. I would find one you can mount to the manifold and run a water cooler block under that, with your normal air to air intercoolers after the turbos.
In my experience, it only works well on roots because at the top end the turbos basically bypass the supercharger through the rotors, the boost was not adding as you put here. To get it to truly compound I would imaging you would need a massive screw type blower that can truly ingest the air the turbos are putting out, but if you go that big on the blower you lose the bottom end again.
Just my experiences with this.
In reply to SpeedAddict502 :
Great info. I wanted to avoid a roots blower because of the heat it puts into the air. Sounds like if I want to stick with a twin screw I'll need a way to bypass the supercharger.
I had a compound charged diesel in a previous life, made cool noises and impressive boost numbers, but was a challenge to get the system right.
With the advancemets in turbo technology in the past few years, I would expet your time, money, overall effort would be better spent on a couple newer turbos
Isn't that supercharger far too small to support your air flow goals?
With a quick google I couldn't find a compressor map but this supercharger was originally designed for a pretty modest application more as an emissions cheat rather than performance.
are you planning on two of them?
Have you figured out how to get the engine to live with that boost level?
In reply to fouckhest :
Yes, very true. I'm just having fun with the project.
In reply to Ando :
It's an interesting supercharger. It was designed for a Miller cycle engine. So it produced 30psi but due to Miller cycle valve overlap the engine only saw around 10psi. My motor is twice the size so I should see around 15psi. Originally I was going to use two, not sure I need to though.
the supercharger arrived and it "fits". It'll move over a bit to where the intake pipe is but all in all there's room. My new plan is to use the Volvo design that uses a supercharger clutch and large bypass. So the supercharger would only be on during low RPMs which means I avoid complex boost situations of a true twincharged setup and I can eliminate the HP loss of powering the supercharger at high RPMs. If possible I'll set the supercharger clutch up to a pressure switch between the turbos and supercharger so as soon as that charge pipe goes from vacuum to pressure the clutch disengages and the bypass opens. I really want to avoid compressing already compressed air, it adds a ton of heat and tuning seems impossible.
the supercharger came with a bypass, I wonder if it's big enough...probably not
Probably not worth an update but hey why not. I've been wrestling with what to do with the back of the roof for a few weeks now. It was a fully roof, then I whacked the back off to open up the engine. I just couldn't get over the aero penaulty that I'm sure its was having so landed on the solution below. I'm pretty happy with it. It follows the countor of the roof (it doesn't buldge like the picture suggests). I was also able to sqeeze the lexan in without removing the LED running/brake light which was a nice bonus.
Wait, supercharged turbocharged here we come. This car just gets crazier.
More plexiglass work, this time with my daughter to help me trace. I really resisted spending the $40 on the sliding window, I was convinced I could make it myself but after seeing the finished product I'm glad I didn't attempt it and spent the money (I bought a kit from Condor made for e30s, its well made). Next I need to tackle the drivers side which will require a frame (since that door opens). Does anyone have any pointers on making an aluminum frame for a lexan window? I'm thinking about using sheet aluminum instead of the AL tubing you normally see. I don't have a welder available at the moment so that makes it a little harder.
In other news I took the car out for coffee last weekend to test out the modified cooling system, its amazing how bad Amazon radiator electric fans are compared to Spal and other higher end fans. Do not trust the CFM claimed by what you find on Amazon. With the new fans in place the car running nice and cool, still completely miserable as you'd expect a racecar to be on the street but its able to do it.
Well I managed to not get a single good picture at Hyperfest but I had a great time and was able to move the build forward. I learned a few things:
1. The boost control is not working, there is actually a wiring problem that would have caused the car to go full boost if I hadn't had also made a mistake connecting the boost lines....
2. The E85 system (which haven't tried to use) need a tweak in the program but is now up and running thanks to Marc at EFI Express
3. The cooling system cannot come anywhere close to keeping up. On boost it quickly gets too hot and I have to let the car cool which preventing me from running more than a couple laps and I couldn't run a full lap at full tilt. But I was able to really beat on it for short amounts of time and everything held together which was great to see. I'm going to add an electric boost pumps and add the stock radiators into the mix (so I'll run three rads). This should fix the problem. I think the main problem is the audi pump trying to handle miles of cooling lines.
Typical track day....
My other take away from the week (simply because I have a problem and can't stop) is I think I should hack the roof off. It was, of course, originally a convertible. I'd have to cut some of the front cage out and the windshield out, lower the seat and add some open cockpit cage adjustments to make it "safe". Has anyone run an open cockpit car? I think it would be a hoot.
In reply to Box4VIR :
I've ran the MG open before. Air management on your helmet becomes a thing like on a motorcycle. Also some track day orgs want a windshield. But otherwise it was pretty cool.
If you could do a bolt on screen that might be a good compromise and keep street ability present.. ish.
nocones said:In reply to Box4VIR :
I've ran the MG open before. Air management on your helmet becomes a thing like on a motorcycle. Also some track day orgs want a windshield. But otherwise it was pretty cool.
If you could do a bolt on screen that might be a good compromise and keep street ability present.. ish.
Thanks for sharing your experience with the MG. I guess I should check on some local laws and HPDE groups first and cut second
You'll need to log in to post.
