JBA long tubes

[wickedwhite2012]

Has anyone on here running the JBA long tubes 1 7/8 from
Moes. I was told that the 1 7/8 where to big unless you put a blower or any type of power adder. Is this true??

 

[oesman]

Has anyone on here running the JBA long tubes 1 7/8 from
Moes. I was told that the 1 7/8 where to big unless you put a blower or any type of power adder. Is this true??

On other domestics 1 7/8 mains were more popular for people going bigger (i.e. blower, heads & cam, etc...) Some say the 1 7/8 is too big for basic boltons. The thought was that you may get less torque gain on the low RPMs as the power band may be pushed up the RPM range without bigger power mods. However I think you'll still get the biggest gains out of 1 7/8 mains if it's anything like the GM LS engines I've worked on. I would just go for the 1 7/8 myself personally. The difference in low end grunt will be negligible compared to smaller mains, you will still get more power all over the range than factory, plus you won't have to swap them out later if you do decide to add FI or other mods beyond boltons.

I was looking at the ARHs myself as I didn't see a Kooks alternative. Never used JBA before, is the build quality any good? They're priced pretty low.

 

[Hemi450hp]

You are ok with the 1 7/8 as long as you have gears or a converter to give you that low end grunt. We have run both 1 3/4 and 1 7/8 on numerous combinations on these trucks, and 90% of truck benefit more from the 1 3/4" primaries. As long as you have a higher stall converter or 4.10-4.56 gears, then the 1 7/8" will be perfectly fine for you.

The above post explained it pretty well. Larger primaries make a bit less tq, but a bit more hp. For a daily driver, the tq is more beneficial, so that is why we push the 1 3/4" so hard. If you are someone that is at the track all the time, you likely already have gears or a converter to make up for the slight tq loss from the larger primaries, so in that case, the 1 7/8" will be fine and will probably net a slightly faster ET.

 

[dtru1222]

I know its a slightly different application but its the same engine, on the 5.7 Challenger there was a user who had a custom tune dynoed then added the 1 7/8 long tubes and gained all throughout the RPM.

I think the thought that Long Tubes reduce low end torque is a myth, or just does not apply to the 5.7

 

[Etroze86]

Not that the 1 7/8 reduce tq just move it higher in the rpm band on our trucks.

 

[Hemi450hp]

They don't reduce tq, the 1 7/8" primary simply makes less tq at the same rpm as a 1 3/4" longtube. Also, the cars are a different story as they are much lighter and make power at a higher rpm. If putting headers on a hemi car, I would without a doubt go with 1 7/8".

 

[wickedwhite2012]

This is a stock 2014 four door with the 8 speed. May be doing a couple of bolt ons and some 3.92 gears later down the road. If the low end torque is not noticeable then I may just go with the 1 7/8.

 

[dtru1222]

They don't reduce tq, the 1 7/8" primary simply makes less tq at the same rpm as a 1 3/4" longtube. Also, the cars are a different story as they are much lighter and make power at a higher rpm. If putting headers on a hemi car, I would without a doubt go with 1 7/8".

Do you have any good comparisons of the two? The only one I have to go off of are my 1 3/4 vs another users 1 7/8 which are producing more low end than mine.

I know you cant really compare the two like this, different car different dyno, but its all I have to go off of.

Kooks Headers Install and Dyno - Dodge Challenger Forum: Challenger & SRT8 Forums

RT before and after ARH Long Tubes - Dodge Challenger Forum: Challenger & SRT8 Forums

Either way my original statement was more towards those who say long tubes will make you lose low end torque compared to the stock set up.