The Dodge Challenger Message Board

Tim wrote:I've got 3.91 gears on mine, which seem to be a nice compromise. I can cruise at 65 doing about 3000rpm, and I'm pulling about 5750rpm going through the lights. I'm not sure the 4.10's would be significantly different?

There is 5% difference between 3.91 and 4.10 gears. That means with the 4.10 gears you will have 5% more torque at the rear wheels and 5% more rpms at the same speed. Top speed will be 5% less.

So it will launch harder (but loose traction easier) and depending on where your cam makes its power it might add some mph at the top end if you are using more of the power curve.

Yeah it would be great to get as many board members as well as their cars together for a group photo. I would like to include ALL board members going to the Nats whether they have a car there or not.

Starting to look the business.

If only it flippin' worked.

GOOD LOOKING CAR. WHAT SIZE TIRE AND WHEEL COMBO ARE YOU RUNNING? THEY FILL THE WHEEL WELL SPACE NICELY. I HAVING A HARD TIME FINDING 14 INCH TIRES TO GO AROUND THE EARLY 70'S ET MAGS THAT I WOULD LOVE TO KEEP. I AM TEMPTED TO GO NU SKOOL AND GET A 17 OR 18 INCH SET UP.

Thanks Brad,

Front wheels are 6.5 x 15's, with 195/ 15 tyres.
Rears are 10 x 15's with Hoosier 295x 15 x 60's. The rears are on a 4.5 inch backspacing, with the leafsprings moved inboard about 2 inches for clearance.

I've seen some very nice looking Pro- Touring style E- bodies on 18's. Much bigger than that seems to make the car look like a Hotwheels toy. I guess it's just a case of getting everything to look proportionally correct.

As Dave kindly mentioned under the Euronats thread, we had a good day with the car at this years event.

Officially down into the 12's now, I need to finish tuning the carb, and then maybe see what we can run with the nitrous on.

Here's the legendary pass, on Hoosier DOT tyres, and through the exhaust.

Cool clip.

I'm a bit worried about all that shit coming out of the left side exhaust pipe though.

Yeah, I noticed that too mate. I think it's still the valve cover breather hazing oil out at high RPM's. That side has always been the worst, and there was a thin covering of oil on the valve cover when I got back. Hopefully that's where it's coming from, and it just appears to be coming out of the exhaust. Having said that, I'll watch the clip again now, just to make sure....

Bad piston ring seal will not only blow oil out of the exhaust but also out of the breather as the pressure builds up in the crankcase.

"Bad piston ring seal will not only blow oil out of the exhaust but also out of the breather as the pressure builds up in the crankcase. "

That's an interesting thought mate. I've been trying to puzzle out how, using last years runs at York as a baseline, I managed to improve the 60ft times by 0.8 seconds, improve the ET by 1.5 seconds, but only gain 3mph? I would have expected to be running 105- 107mph, so maybe I'm losing some horsepower as the ringseal goes away at higher rpm? This makes a lot of sense, now I think about it.

Could bad ringseal also contribute to higher running temperatures?

I am not sure that rpm is a factor in power loss except that more oil is thrown up under the pistons at high rpm so you burn more.

I would imagine that cylinder pressure would be actually better at high rpm because a) the gas has less time to escape past the rings and b) the oil coming up helps seal the rings.

I would have suggested poor valve stem seals as a source but I know you have just fitted new edelbrock heads so that can't be it.

I have been having a good old think about what might be happening in your engine.

I don't know how good the cylinder bores are in your engine or how long the piston rings have been in there but I suspect some of them are worn.

You were running it in a very rich condition for quite a while. This washes the cylinder walls as well as thinning the oil. A good reason to tune a carb before doing a lot of driving. High fuel pressure will do the same thing.
Fuel might even have been pooling in one or more cylinders.

Over the winter you should do a compression check on every cylinder. Because the heads are new you can rule out leaking valves. Any low compression or leak-down must be to do with the piston ring seal.
If they are indeed bad you need to deal with it.

If they are all just generally leaky a fresh set of total seal rings and cylinder hone might do the trick. The bore will have to be measured though to see if it is wearing bigger than the pistons would like.

If one or two cylinders are bad and the others good you might just have worn or damaged rings on those cylinders.

In any event you will need good piston and ring seal before you try the NOS. In fact you should fit a top ring designed for NOS use. If you are going to use more than just a small amount of NOS you are going to need forged pistons anyway.

Many thanks for that Dave, I was thinking along the exact same lines.

The pistons/ rings are just about the only unknowns left in the engine now (maybe the crank, but I think ours are built to last?). I saw an article in the last Mopar Action magazine, advising that one of the manufacturers are doing piston rings built specifically to withstand nitrous abuse, so they may be the way to go.

I'll be keeping the nitrous under 125hp, which means I should be able to get away with standard pistons, as long as I make sure the engine doesn't run lean. Any bigger shots than that and you have to get into swapping plugs and all sorts. Not worth it for me, I want to drive home after .

Having said that, if everythings looking a bit worn, I'll definately fit a new set of pistons over the winter, and fit new rings at the same time.

I've got a day off today, and have been dodging showers all morning trying to finish the carb, and wrap the headers to try and stabilise the fuel pressure. I know, I know............

Cool photo of your car taken by Dave McBride at www.dodge-charger.co.uk

Thanks for the photo Dave.

Dave McB took some stunning photo's at the Mopar Nats, and was kind enough to e- mail the full- size versions of my car to me. Took me about 5 hours to download, but well worth it. The blokes got a real eye for a good picture.

I was hoping to get a couple of final runs on the car this year before the season ended, but personal circumstances meant I couldn't make it to any of the late events at Stratford. Shame, because I was intrigued to see if we could run quicker with the carb set up properly, and cooler dense air to make use of. I had a sneaky hope that we might run a 12.80, which was always the target for the car. I was even toying with the idea of making the final pass of the year with the nitrous on, and see if we could squeek a sub- 12.50 out of it, which would have given us a good starting point for next year.

Never mind, the cars' waiting in the garage for next season. In the meantime, if money allows I'll try and get the correct pistons fitted to go with the Edelbrock heads, and bring the compression up to where it should be, and fit some Hellfire NOS- proof rings at the same time. Then we're all set...

After that, it's saving to buy replacement fibreglass panels for the Great Mopar Makeover. The idea is to replace the rear quarters, trunklid and bumpers to get some weight of the car and make it look more presentable at the same time. The decrease in bodyweight will hopefully yield some improvement on the track, but also make the car handle better in daily driving conditions, and de- stress the drivetrain a bit on hard launches.

Once all that's been achieved, and the car's been resprayed, it's officially finished.


Yeah right....

Forgot the important bit....

Fit a pair of subframe connectors before the car pulls itself in half!

It never ends......

I would be a bit worried about plastic rear quarters on anything other than a full tube chassis type car. They are very structural!

Bugger!

Thanks Dave, now I remember you telling me that the floorpan of the trunk is connected to them in some way. I'd forgotton that.

Time for a re- think. Do the front quarter panels do much in terms of holding things together? It would make more sense to get weight off the front for handling and weight transfer off the line.

Keep the steel inner fenders/radiator support and make sure the stock (or better) brace under the fender is in place. Then you can run plastic front fenders, plastic bumper, plastic valance.

You could use a plastic rear bumper and trunk lid.

If your roll cage extended into the engine bay and you fabbed a radiator support and upper front suspension mounts then you could loose the inner fenders too but I don't think it is worth the hassle.

"If your roll cage extended into the engine bay and you fabbed a radiator support and upper front suspension mounts then you could loose the inner fenders too but I don't think it is worth the hassle."

I agree mate, that cage is so heavy, I'm sure I'd be putting in more weight than I'd be taking out. Plus, it would be getting a bit too 'race car' for my liking.

I did this.

Sorry.

If you washed the car more people wouldn't be able to write stupid things in the dirt.

I got you one for your car, for Christmas.

Barr! Humbug!

Took all the old race stickers off at the weekend. And some paint .

Looks better without overall.

Sharp looking Drag Car Tim! That color is unusual and rare! I used to dislike it when I was younger but now it looks classy! I read and downloaded very cool! Did you figure out the problem? Sounds pretty healthy, maybe a little blowby? 12s are nothing to scoff at!

airfuelEddie wrote:12s are nothing to scoff at!

Time-slips talks, bullsh-t walks?

Thanks for the feedback chaps.

I think Dave had it right when he figured my piston rings needed replacing. They still do. I haven't really had the money to improve the car the last two years, which is a shame because we were really starting to get somewhere.

If I could invest another £3000 in it, I could get the car just how I want it, and use it a lot more too. But how many of us have said that....

The car was originally white, with a vinyl roof. Someone did a roughish respray at some point in the past. I'm not sure what the exact colour is, I suspect VW something or other, but it's not a bad match.

Tim wrote:If I could invest another £3000 in it, I could get the car just how I want it, and use it a lot more too. But how many of us have said that....

Sounds like me in a nutshell.
The strange thing is that when you have used the £3K, you realize that you need another £3K.

Oh yeah, it will never end, ever.

hi tim I was looking for my old car on the internet and found you now have it. i got it originally with blown 318 engine off dave hallows when i lived in west wickham. kent. ordered a 440 from rodley motors and built engine and put on road approx 1987 had it for approx 15 years and then gave to my "mate" gary goode who sprayed it yellow. he was meant to give me back the engine but that was the last i saw of it. have got some photos of original build up etc. car ran 14.33 on street tyres first run at the pod. catch up with you later andy