Trying to get rid of some things

-
If the charcoal canister vapor return system is still intact, I would leave it on.
 
Jmcginnis89 said:
Are turbos that big of a hasel and do u think I can get a good amount of performance out of just a engine build or turbo?
Click to expand...

I like the idea of a turbo /6 and there are some out there that run really hard-- but to me, it is a ton of work and hassle to get it "right".
It is never as easy and cheap as some make it out to be. Forgot about bolting it on and going fast. Prepare for lots of tinkering.

But this is my opinion and I just prefer to make a slant run hard naturally aspirated.
 
DusterKrazy said:
Right on!! Talked to a few guys running 11:1 + with them and no issues. I can't find the .080 ones anymore though....
Click to expand...

summit racing,(Sealed power W244NP80 is i recall)that where i got mine... have to go to total seal for the rings

OP. the above was for a turbo base but enough motor to get you by... a true na build will have more like 10:1 compression. bump the cam up to the 230 @ .050 and about .500 valve lift .370-.390 lobe lift on stock rockers. 106-108 LSA installed 4 degree's advanced. nice lobe and runner up to 5800 or so on pump premium.

gonna want a 600 vac secondary holley carb, dual 2.25 into single three inch.

what headers? hookers of cliffs?
 
I have a set of Clifford headers a y pipe and a set of thrush mufflers just haven't made it that far yet just have a lot of parts so far
 
805moparkid said:
hmm... i think dual 2.25 into single three with a flowmaster, i would go delta flow 50 or 40
Click to expand...

I don't have a lot of experience with slant sixes, but in closely-reading reading four years of posts on FABO I have gained a little knowledge (I HOPE) and of COURSE, have an opinion about what you are doing, or are trying to do.

I would advise you to RIGHT NOW, set some performance goals for this car (which is really a nice one, by the way!) and be specific about it.

I mean, you need to RIGHT NOW, decide whether a 14-second car is going to be fast enough for your own, particular, need for speed, or whether you would think that such a car was a "stone," and lust after e/t's on the 12's... or, faster.

The reason I am advocating such action is that you seem to be leaning towards doing this exercise with a normally-aspirated motor.

A 14-second car is not "slow." Most new 340 Dusters and 383 Road Runners were mid-14-second cars when they were new, on the stock rubber of the time. That's about 98 mph.

Building a street driven, normally-aspirated 3,300-pound car that runs appreciably faster than that with a 904 and a 225 slant six is not really all that easy, if you want to maintain the driveability and gas mileage in a near-to-stock area.

The '68 Dart of our 305Moparkid is a case in point. He knows what he's doing and has done a good job of increasing the performance potential of that car with the standard hop-up procedures that most folks use on normally-aspirated engines; those include (but, are not limited to) raising the compression ratio, adding a 4bbl carb on a 4bbl manifold, re-curving the distributor, adding headers, installing a high-stall torque converter, changing the rear axle ratio, installing a long-duration, high-lift cam and adding some lightweight sheet metal. I think it has a ported head with bigger-than-stock valves. Slicks.

I am sure he's probably done some things I forgot to mention, but what he's done is likely what YOU might do to your normally-aspirated car... nothing radical, but attacking the horsepower challenge on many fronts.

His car has run a best of 14-flat... quicker than a 340 car on street tires, but his best time was on slicks, so a stock 340 Duster on slicks might give him a good race. At any rate, that's how it runs.

IF that is about as fast/quick as you feel you want your car to go, then I would say, "Go for it!!!" That would be a fun car and would NOT break the bank. I think he's knocked on the door of 100mph, but has yet to go through it... could be wrong about that. Most 340s wouldn't exceed a 100mph quarter-mile, stock, either.

But, what you'd have there is a "fun car" with a rough idle, an appetite for something better than 87 octane, and not real good gas mileage, because in order to make it a "quick-as-a-340" car, you'd need a hi-stall converter and at least a 4.10 gear.

Let's say you get that sucker built and are running 100mph with a 14-flat e.t., and it just doesn't feel "fast" to you, any more...

You want more...

Having exercised a good many of your options in getting it to run as fast as it does (and, a 14-flat car feels "fast" to ME,) you have passed the point where cheap upgrades pay significant dividends in the e.t. department... it now takes a LOT OF MONEY to go much quicker... normally-aspirated.

So, you look at the next step... forced induction.

I am by-passing nitrous oxide here, for a variety of reasons, but it would be another possibility for performance increases. I know so little about it though, I am in NO WAY qualified to write anything about it.

Forced induction comes in several varieties, and they are all good.

The problem with trying to milk significant horsepower out of a N/A 225 slant six lies in the fact that the cylinder-head was originally designed for 170 cubic inches.

When they stroked the 170 a full INCH, to get 225 cubes, they did NOTHING to the head... nothing. Same smallish valves and ports, which created an engine that has a bad case of asthma... and there's not much that can be done about the breathing ability of that head, in spite of some heroic measures that include bigger valves and opened up ports. Think about running a marathon with your mouth duct-taped shut.

The "oversize valves" that go into a slant six head are 1.75" (intake) and 1.5" (exhaust). You can get bigger vales in there, but it is at the risk of shrouding the sides of the valves on the combustion chamber walls. The problem comes from the 3.4" (small) bores. Just no room...

By comparison, the 1968 302 Z-28 302 Chevy has the exact same CYLINDER DISPLACEMENT as a 225 slant six (39 cubic inches) and comes stock with 2.02" and 1.62" valves. Wow...

They breathe pretty good, but it takes valves of that size to make them do so.

What to do???

The slant six engines I have seen that perform best with forced induction are turbocharged. But, you could also do it with a Paxton/Vortec/Pro Charger centrifugal supercharger, or a GMC 4-71.

YOU pays your money and you takes your choice.

The slant six basic engine infrastructure is SO STRONG that it will take a LOT of abuse from forced induction before it complains. That comes, I think, from the fact that it was originally cast in aluminum and when that didn't work out (60,00 aluminum ones were built before MA Mopar threw in the towel,) they changed very little as they switched over to cast iron. (It helps that the crank is short, and forged, with main bearings the size of the 426 Hemi's.)

Some guys are running boost levels approaching 30 pounds with no apparent ill effects, and producing over 500 horsepower.

But, you probably are going to opt, instead for a 300hp street motor, which only takes about 10 pounds of boost (witha big-valve, ported, head) to achieve.

The trouble is, boosted engines don't LIKE compression ratios much over 9:1, so, if you mill your block, it will force you into a position of probably having to buy some expensive, custom pistons if you want to run a turbo, later.

My advice, if you think 14-flat isn't going to be fast enough for you, and you'll likely want a turbo down the road, is to follow Charrlie Schmidt's advice and build the turbo FIRST and you'll not waste money on buying a different cam and pistons, (and probably rods) later.

Then again... like I said, a 14-flat car can be a LOT of fun!!!:blob:

A ten-pound boosted turbo car with alcohol spray to cool the charge, would likely run mid-12's... with more to come if you decided to O-ring the block for more boost.

It's YOUR money...


But, you NEED to decided exactly how quick you want this car to be capable of. NOW, before you spend any money... twice.:eek:ops:
 
If you go really high compression, you won't be able to turbo it later. But from what I've read, turbo is a real pain and takes a long time to setup and tune. Doesn't seem worth the hassle when I've seen N/A slants in the 11s.

If this is street/strip I would aim for mid to high 9s compression. Cut the car's weight where possible, run headers and 2bbl carb with 2 1/4" exhaust. Electronic ignition, and dump all that smog stuff.
 
Otateral said:
If you go really high compression, you won't be able to turbo it later. But from what I've read, turbo is a real pain and takes a long time to setup and tune. Doesn't seem worth the hassle when I've seen N/A slants in the 11s.

If this is street/strip I would aim for mid to high 9s compression. Cut the car's weight where possible, run headers and 2bbl carb with 2 1/4" exhaust. Electronic ignition, and dump all that smog stuff.
Click to expand...

Show mw a slant six poowered car in the 11's that hasn't been subjected to a SERIOUS weight reduction program.

Most A-bodies that are street-driven weigh at LEAST 3,000-pounds. It takes 345 horsepower to run a 11.98 at that weight.

You're not going to see that out of a normally-aspirated slant six... especially not a streetable one.

If I am wrong, show me one. I'll apologize!

But, you are right about one thing; a turbocharged slant six is anything BUT easy to put together in a fashion that will perform like it should. Takes time and tuning...

Not an easy build... but, the rewards are great, IF you can get it done...

So....... it's not for everyone, granted.
 
To return to your original question, most of the vacuum stuff is for EGR and gas fume recovery (charcoal canister). The big round box on the intake manifold is a "vacuum amplifier", as I understand. Indeed, my 85 M-B has a similar but smaller device. I think if you disconnect the tube to the EGR valve, it will stay closed. A guy on ebay sells a block-off plate for ~$15, however you may want to change the intake anyway, to a 2bbl or 4 bbl. I don't think the charcoal stuff hurts, as long as it is all working. It might even slightly improve your mileage by recovering gas. If you change to an EFI setup (few have done on a slant), it would serve no purpose since no carb bowl to evaporate.
 
I agree with BillGrissom made in the his previous post. I'd leave the charcoal in because it vents the fuel tank as well. Cap the nipple from the carb bowl.

The Offy and Hurricane 4 bbl manifolds do not have EGR provisions, so those hoses can be tossed. On the other hand, the 2 bbl manifolds from Mopar do have EGR provision. I'm not a fan of non-computer controlled EGR, so the farther that junk can be tossed, the better.

It appears that this is an original factory A/C car. If the heater control valve does not work, you would be able to remove it and replace the two hoses going to it with one. Make sure the vacuum line to it is capped off. The vacuum accumulator on the passenger inner fender should stay as it helps work the vacuum dashpots that open and close the heater/defroster doors under the dash.

In my experience, turbochargers tend to be unhappy when rode hard and put away hot. Bearing lube tends to cook in these situations. The 'coke' that forms in the bearings breaks up and chews at the seals when the engine is fired up the next time. Water cooled bearings and letting the vehicle idle for three minutes or more prior to shut down minimize the coking situation.
 
2 Darts said:
In my experience, turbochargers tend to be unhappy when rode hard and put away hot. Bearing lube tends to cook in these situations. The 'coke' that forms in the bearings breaks up and chews at the seals when the engine is fired up the next time. Water cooled bearings and letting the vehicle idle for three minutes or more prior to shut down minimize the coking situation.
Click to expand...

I think you're 100% keyrect!!!

So, don't put 'em away hot! Let them idle long enough to cool down to avoid the very real problems you mentioned.:toothy7:
Good advice from 2Darts!
 
You must log in or register to reply here.
-

Back
Top