Nitrous 1994 Explorer

[Awon2zip]

I dont think exhaust mods on a basically stock motor (IE no cam or head mods) is worth much as far as power.i know headers dont even gain you a hp with stock heads,valves and cam..

Personally id spend it on efan or under drive pulley..both are proven to release hp

Good to know. Which efan and under drive pulley do you recommend?

 

[jd4242]

Good to know. Which efan and under drive pulley do you recommend?

Efan would be custom. Search around on here for ideas.
The under drive isnt cheap,its listed for a 4.0 sohc mustang. Its the same

 

[Awon2zip]

Efan would be custom. Search around on here for ideas.
The under drive isnt cheap,its listed for a 4.0 sohc mustang. Its the same

Thanks for your help. I'll be sure to update once i do the 75 shot

 

[Anime]

Would a larger exhaust help my ET?

Perhaps. Depends what size exhaust you have on there now.

93-94 came stock with 2.00" exhaust, 91-92 came stock with 2.25" exhaust.

The 2.25" flows a LOT more, and seems to be best for the 4.0L OHV performance wise. Dynomax's 17747 muffler with a 2.25" in/out is what they spec for the 91-92 Explorer and flows a lot more than a 2.00" in/out.

If you already have a 2.25" muffler and pipe, going to 2.5" might be overkill, then again maybe not if you are going all the way to redline with the boost.

The 2.00" is best for street for quiet/no drone, the 2.25" is best all-around for torque/sound/performance, 2.5" would probably be best for track use, if you have the air flow mods to need it.

 

[Awon2zip]

Perhaps. Depends what size exhaust you have on there now.

...

If you already have a 2.25" muffler and pipe, going to 2.5" might be overkill, then again maybe not if you are going all the way to redline with the boost.

I only got the 2.25" dynomax muffler. Should i upgrade to the 2.25" exhaust pipe? both the mid pipe and the end exhaust pipe?

 

[Anime]

I only got the 2.25" dynomax muffler. Should i upgrade to the 2.25" exhaust pipe? both the mid pipe and the end exhaust pipe?

Which 2.25" muffler did you get? Dynomax makes a 2.00" in/2.25" out specifically for the 1993-1994 Explorer, which is way better than the stock 2.00" in/out but still a bottleneck since the crushed 2.00" pipe between the cat and muffler inlet goes down to 1.75" or so at the bends.

If you have the 17731 Dynomax Super Turbo that's a shorter muffler but still 2.25" in/out, that doesn't flow quite as much as the longer 17747 but is still pretty good.


No matter what muffler you choose, the Dynomax 45493 tail pipe will give better flow since it's mandrel-bent (constant diameter).

With the shorter 17731 muffler, you can use the stock Walker 43470 2.25" cat to muffler pipe for a 91-92 4-door if you want a semi-bolt-on DIY install, but you will need to come up with a hanger solution for the back of the muffler as the 93-94 single hanger won't be in the correct position with the 91-92 cat-to-muffler pipe. If you have the longer 17747 muffler you will need to find the 42063 cat-to-muffler pipe for a 91-92 2-door. If you have the 93-94 specific muffler with a 2.00" inlet, you're stuck and can't really do much with the cat-muffler pipe.

Another (possibly better) option is if you can find an exhaust shop that mandrel-bends tubing, they can probably make you the cat-to-muffler pipe in a custom config that lets you use what you have now, then you just add the 2.25" Dynomax tailpipe yourself. If you have a 2.00" muffler inlet it's still going to be a heck of a bottleneck.

I'd also highly suggest using band clamps on the muffler/pipes as well if you aren't already, the standard cheap U-clamps crush the tubing and reduce the diameter as well. Keeping the exhaust tubing round and the same diameter all the way back makes a really big difference in flow and performance.

I didn't think it would make as much difference as it did, even on a stock 4.0L OHV, but 2.25" pipe from the cat to the end with a 2.25" in/out Super Turbo muffler made a BIG difference in acceleration, even just in daily driving from 0-3000 RPM. I'm pretty sure it makes a big difference from 3000-redline as well, since that's when there's even more exhaust volume and higher flow.

You also don't want the exhaust to be too much of a bottleneck since it can burst and fail spectacularly on the strip. It'll also be worth it for both safety and saving yourself the embarassment of holding everything up because the exhaust winds up going all over the place.

 

[Awon2zip]

Which 2.25" muffler did you get?

I actually made a dumb mistake while back of getting the super turbo with the 2.5 inlet/outlet. I just got a few adapters to fit the pipe. :thumbdwn:

Sure sounds great though

 

[Anime]

I actually made a dumb mistake while back of getting the super turbo with the 2.5 inlet/outlet. I just got a few adapters to fit the pipe. :thumbdwn:

Sure sounds great though

Might not be a dumb mistake!

Because of how the Super Turbo works (s or e shaped flow) the 2.25" mufflers are more restrictive than a 2.25" pipe.

So, using that 2.5" muffler with 2.25" pipe and 2.25"/2.5"adapters would give you more flow than the 2.25" Super Turbo. The 2.25" 17731 flows 373 CFM, the 2.5" 17733 flows 410 CFM. Not a huge difference but enough to give more headroom to the extra horsepower on the bottle.

The only downside of the 2.5" muffler might be that a less restrictive muffler might drone at certain RPM, and you might not have as much torque at very low RPM.

If you're using a 2.5" muffler with stock size 2.00" in pipe, yeah, either get the Dynomax 2.25 tailpipe and Walker 2.25" cat-to-muffler pipe, or have an exhaust shop fab you up some 2.5" pipes. You can get away with crush-bent 2.5 pipes from any decent shop since they will only crush it to 2.25" at the bends.

It's hard to say whether the 4.0 OHV would do better with 2.25" or 2.5" pipe under nitrous, but I know for sure it's a lot better with 2.25" than 2.00". If you have future plans for even more engine mods, I would guess that custom 2.5" pipe might be the better investment. If you want to keep it DIY the 2.25" Dynomax/Walker pre-made pipes are hard to beat. They flow plenty for the street and would be a heck of a lot less of a bottleneck than 2.00" pipe if that's what you have now.

 

[jd4242]

Like i said..the ohv most bottle neck place is its valves,its not like the SOHC which has much larger valves and heads flow much much better..

I know the ohv has been dyno with and without headers and saw no gains,it didnt mention what exhaust changes were made but sure they didnt do headers only..this again was all on a stock motor with intake..im looking for the threads..to me any gains that might make a difference for exhaust mods would come from high flow cats and high flow muffler or a combination of stuff,not just new mid or tail pipes

Efan is good for releasing 6-8hp and under drive are good for about 12-15hp and i saw about a 3-4 mpg increase as well..this has been proven time and time again and doesnt matter what other mods you have because its releasing hp that you already had..

Its like the people who drop $6k for a turbo setup and only running 6lbs of boost making 60hp when you can drop $400 for a nitrous kit and make more power. .which would you chose

 

[Awon2zip]

Efan would be custom. Search around on here for ideas.
The under drive isnt cheap,its listed for a 4.0 sohc mustang. Its the same

checked my fan blade today and discovered it has multiple cracks in it...looks like i'm gonna get an efan. Would this fan work? http://www.amazon.com/TYC-621450-Chevrolet-Replacement-Condenser/dp/B001DH0QSU/ref=au_as_r?_encoding=UTF8&Make=Ford%7C54&Model=Explorer%7C663&Year=1994%7C1994&ie=UTF8&n=15684181&newVehicle=1&s=automotive&vehicleId=1&vehicleType=automotive

I saw in an old post you had this one

 

[jd4242]

checked my fan blade today and discovered it has multiple cracks in it...looks like i'm gonna get an efan. Would this fan work? http://www.amazon.com/TYC-621450-Chevrolet-Replacement-Condenser/dp/B001DH0QSU/ref=au_as_r?_encoding=UTF8&Make=Ford%7C54&Model=Explorer%7C663&Year=1994%7C1994&ie=UTF8&n=15684181&newVehicle=1&s=automotive&vehicleId=1&vehicleType=automotive

I saw in an old post you had this one

It didnt work out for me but i had a single core radiator at the time and 4x4 in high 90*...my buddy i believe still uses it on his truck and hasnt had issues. .could try it,its cheap for sure

I use one from a supercharger thunder bird..its the same fan motor as the Taurus fan that everyone uses but has a different blade design and moves more cfm

 

[Awon2zip]

I use one from a supercharger thunder bird..its the same fan motor as the Taurus fan that everyone uses but has a different blade design and moves more cfm

would i need a 1994 Taurus fan?

 

[jd4242]

would i need a 1994 Taurus fan?

People seem to have more success with the Taurus fan for sure

 

[Awon2zip]

People seem to have more success with the Taurus fan for sure

Sweet. Might go to the junkyard and see if i can find one in good condition. I was having trouble finding the right underdrive pulleys. How much do they usually go for?

Also what about camshafts? Any worth putting one in an explorer?

 

[jd4242]

Sweet. Might go to the junkyard and see if i can find one in good condition. I was having trouble finding the right underdrive pulleys. How much do they usually go for?

Also what about camshafts? Any worth putting one in an explorer?

http://m.summitracing.com/parts/asp-526400

Yea camshaft is definitely worth it but the heads need to come off to put one in.also need 988 dual comp cams springs and the head spring seats need to be milled for them to fit,as well as longer pushrods..worth every penny but not a easy job

 

[Awon2zip]

http://m.summitracing.com/parts/asp-526400

Hmm. I don't know if $230 is worth 12-15hp. It would be nice to have that extra hp around town and increased mpg

 

[jd4242]

Hmm. I don't know if $230 is worth 12-15hp. It would be nice to have that extra hp around town and increased mpg

The gained mpg would pay for it probably in no time..like i said its not cheap but compare it to that high flow cats or mid pipes and rear pipes that cost you more and may gaun you a hp or a mpg

 

[Anime]

Putting in a performance cam is a pretty expensive thing since the cost snowballs with all the other stuff that goes along with it. The 410 cam is supposed to be mild enough to work with stock components, but may not be worth the cost, at least compared to saving up for the rest of the stuff to do the 422. Like jd said, you will need dual springs, milled seats, and really, I would say you should get new heads since the aftermarket heads flow more and are thicker and stronger than the stock Ford parts. Add in the porting and polishing and valves and you are looking at a pretty good chunk of change.


The exhaust pipes are worth it in a lot of ways - keeping stock crush-bent 2 inch pipes on there just wastes a lot of power pushing the exhaust out.

Look at the numbers to see for yourself:

1.75 in pipe flows ~240 CFM
2.00 in pipe flows ~320 CFM
2.25 in pipe flows ~400 CFM
2.50 in pipe flows ~500 CFM

The crush-bent 2.00" pipes are really ~1.75" or so at the bends.

Right now the pipes are the bottleneck since the cat is 2.50" and the muffler is 2.50" with about a ~400 CFM flow. Even just going to the 2.25" Dynomax rear and Walker cat-to-muffler pipe will up the capability of the exhaust to ~400 CFM.

It's certainly true that the stock heads are the bottleneck at the intake, and the stock mass airflow sensor housing and throttle body are bottlenecks too, but I can tell you from my own experience that sticking a 2.25" catback exhaust on a 93-94 Explorer gives some pretty impressive power and torque gains over the stock 2.00" tubing. It won't be as dramatic as if the muffler were also a bottleneck, but every little bit helps.

You could always just get the 2.25" intermediate cat-to-muffler pipe and use an adapter, or have a 2.50" pipe made, then dump the exhaust before the axle and do some test runs to see what the difference is before springing for the expense of a larger diameter tailpipe.

 

[Awon2zip]

You could always just get the 2.25" intermediate cat-to-muffler pipe.

I can only find exhaust pipes with 2.00" diameter such as this one http://www.summitracing.com/parts/wlk-41672/overview/year/1994/make/ford/model/explorer. Got a link to a 2.25"?

EDIT: Would a 2.5 inch pipe be overkill?

 

[Anime]

I can only find exhaust pipes with 2.00" diameter such as this one http://www.summitracing.com/parts/wlk-41672/overview/year/1994/make/ford/model/explorer. Got a link to a 2.25"?

EDIT: Would a 2.5 inch pipe be overkill?

This is the Dynomax 45493 2.25" tail pipe for a 93-94:

http://www.summitracing.com/parts/wlk-45493


This is the Walker 43470 2.25" intermediate pipe for a 91-92 4 door Explorer:

http://www.summitracing.com/parts/wlk-43470

If you have a Dynomax 17733 muffler (14" body, 18" overall) then you can use the 4-door pipe in the front, and just cut it to length to fit on the 2.250" to 2.25" adapters. Don't cut the tailpipe.



There are 2.50" cat-back systems for Explorers, Gibson still makes one, so 2.50" might not be overkill. I would say a 2.25" system is near-perfect for a street/off-road Explorer, but your limiting factor is the muffler - the 2.50" in/out Super Turbo mufflers only flow ~400 CFM, about the same as a 2.25" pipe. Even a 2.75-3.00" system only flows 20-40 CFM more, so your big jump is moving from 2.00" pipe to 2.25" pipe, going to 2.50" would just give you a little more CFM and some headroom under boost if it benefits from it.

I would say do what gives the most bang for the buck. The tailpipe is about $40 and the intermediate pipe is about $15, plus shipping, so if you can get a 2.50" front and middle pipe bent up from a shop for less than that, sure, go with that. I'm going to guess that an exhaust shop would charge more than you can buy the pipes for, but also keep in mind you'd have to figure out some way to hang the muffler since the 2.25" Walker pipe moves it so it's horizontal and not hanging diagonal on the single stock hanger.

You can always get an exhaust shop to make a 2.50" pipe from the cat to the muffler, then use the Dynomax 2.25" pipe for the rear. Since it's mandrel-bent and since exhaust gas cools as it goes farther back in the system, you don't need 2.50" pipe all the way back to get the flow benefits. This would also let you get the muffler mounted however you want, or at least within the constraints of the rear pipe, which is going to put the center outlet in the same location as the stock 2.00" pipe if that's what you're using now.


Do you have any pics of the current exhaust and how the muffler is mounted?