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-   -   any benefit to ported TB + TBS? (http://www.jeepgarage.org/f183/any-benefit-to-ported-tb-tbs-60857.html)

816jared 06-02-2013 11:42 AM

any benefit to ported TB + TBS?
 
title of the thread asks it all...

I have a '05 4.7, and the way I understand it is, the goal for most mods for that motor are just to increase the velocity of the airflow. One would think that adding a throttle body spacer to a ported throttle body would be one way to help accomplish this.

it might not even fit?

another question I have is, when starting to replace stuff to help with those airflow restrictions is it better to start from the back and work your way forward? or vice versa? (exhaust and work forward, or CAI and go back)


thanks for any input!

jeepgcoman 06-03-2013 01:51 PM

Re: any benefit to ported TB + TBS?
 
My 5.7 is somewhat modified, and I've just added a BBK true 85mm throttle body. So far, the only differences I see are maybe slightly less throttle response and a little less top end power. It's pretty difficult to accurately gauge, but that's the way it feels to me. Might take it to the drags this weekend to see if there is any change.

So, IMO, throttle body spacers are about as useless as it appears ported throttle bodies may be, especially on a stock engine. The only thing it is doing is effectively adding a little length to the intake. If it were tapered down a little, it would accelerate the intake charge slightly. On the 5.7 (and I am sure the 4.7) the exit from the airbox is ~4 in. and tapers down to the size of the throttle body at the manifold inlet. Once it enters the plenum, which is much larger, the air velocity will slow down (expand), and even cool ever so little.....compressed air (venturi effect), up to the butterfly tends to be a little warmer (compressional heating), and expanded air, after the butterfly on the manifold side, tends to be slightly cooler.

You are correct, to a point, about increasing air velocity, but the velocity is limited by intake, internal engine specs/components, and exhaust. Obviously, less restriction of the flow through the engine will help promote maximum possible velocity. We also want the maximum possible volume (again, fewest restrictions in the system) passing through. Volumetric efficiency (VE) is a measurement of how well the engine breathes. The better the breathing, the higher the VE. To put it another way, VE is the ratio of the air mass entering the engine compared to the air mass the engine displacement would take in if there were no losses through it. A normal stock, low performance engine will have a VE in the neighborhood of ~70% and a high performance one about 80%, all out race street engines, maybe 90%. It is possible to get to ~100%, but not at all likely on a daily street driver. The things that help increase VE are specific to a given engine and include, highly tuned intake and exhaust systems, efficient cylinder heads (porting and valve size), and a cam designed to take full advantage of these items.

So, in our cases with the WK's (all engines), IMO, it is best to improve on the weakest links first and then work toward improving the items that are already pretty good. I can tell you the way I went on mine, but it is something you'd decide yourself, based on your ultimate goals, cost, difficulty to modify, etc. Start with the easiest, cheapest things. I started with modifying the intake, only because I had one laying around that I could adapt, and it only cost about $10 to modify and install. Normally, I wouldn't start here though, because our intake systems are pretty good stock. Just try to make the inner part of the system (tube to plenum) to be as restriction and turbulence free (smooth) as possible. I then chopped about one inch off the EGR tube in the intake plenum. The weakest link, IMO, is the exhaust system, especially the exhaust manifolds, followed by the muffler(s) and tubing size. This is the second thing I did, and it made a significant difference with the custom headers and system. It is important not to go too big on the tubing though. Tuners were next. This will make everything happen (timing/fuel mixture, etc) when it should to develop more power. I then went with a well proven (dyno and performance) aftermarket cam that I advanced an additional 2 degrees. I did this same mod. on my Hemi LX and advanced it 6 degrees.....much better fuel economy (~27-30 mpg), but lousy top end. But, then again, how often do you drive around above 5000 RPM? This, along with the other mods, gained a bunch of performance and about 4-5 mpg better fuel economy. Stock, on the highway, I was at about 17-18 mpg and now (most of the time) I am at ~20-23 mpg (last trip was 21.5 mpg with head wind). I am staying away from the heads, because the gain for the $$ is not that much (maybe 30 hp. for ~$2000), and it requires a semi major engine tear down.

Strongjeff 06-03-2013 04:23 PM

Re: any benefit to ported TB + TBS?
 
Tb spacers are useless on these engines as fuel is sprayed into the ports just before the intake valves. the point of a tb spacer is to better optimize fuel atomization and is best suited for carburated motors.

A ported tb that is tapered is your best bet at allowing more air into the motor, while maintaining the air veloceity.

on a 4.7 i would recomend a TB, cat back exhuast and a programer to be most effective.

Alex47er 06-03-2013 04:38 PM

My next project is a tb I heard from other members that is the way to go. I already have a K&N cai flowmaster super 40 and might run with a fastman tb check it out let me know what you think

Strongjeff 06-05-2013 10:47 AM

Re: any benefit to ported TB + TBS?
 
Quote:

Originally Posted by Alex47er (Post 834259)
My next project is a tb I heard from other members that is the way to go. I already have a K&N cai flowmaster super 40 and might run with a fastman tb check it out let me know what you think

go for it,and if you can find them, try getting headers. you will have to saerch them for an 05 and up liberty, no worries tho they bolt right up on a wk 3.7

Alex47er 06-05-2013 01:39 PM

Quote:

Originally Posted by Strongjeff (Post 835561)

go for it,and if you can find them, try getting headers. you will have to saerch them for an 05 and up liberty, no worries tho they bolt right up on a wk 3.7

Really ? Hmmm haven't thought of headers ill look into it thanks man!

Strongjeff 06-05-2013 06:17 PM

Re: any benefit to ported TB + TBS?
 
Quote:

Originally Posted by Alex47er (Post 835672)
Really ? Hmmm haven't thought of headers ill look into it thanks man!

no prob man, i got pics up in the 3.7 performance love thread and videos too. gotten the headers from summit racing

Alex47er 06-05-2013 07:27 PM

Quote:

Originally Posted by Strongjeff (Post 835840)

no prob man, i got pics up in the 3.7 performance love thread and videos too. gotten the headers from summit racing

What other mods have you done?? Deff look into them now cause I rarely see people in a 3.7 with headers your on YouTube?

Strongjeff 06-09-2013 08:12 PM

Re: any benefit to ported TB + TBS?
 
Quote:

Originally Posted by Alex47er (Post 835884)
What other mods have you done?? Deff look into them now cause I rarely see people in a 3.7 with headers your on YouTube?

im on youtube , look up strongjeff1, that's me. all my mods are in my sig.

Strongjeff 06-10-2013 11:16 AM

Re: any benefit to ported TB + TBS?
 
heres the link to my youtube channel

strongjeff1 - YouTube

jeepgcoman 06-13-2013 03:42 PM

Re: any benefit to ported TB + TBS?
 
Looks like that V-6 moves that 5000 lb. slug WK along pretty well. A long time ago I used to mess with the 6's, and most of them have quite a bit of potential, if you can find the parts to build them. I used to love to beat small block V-8's. Don't know if they're still around, but there used to be a place called Clifford Research, and they used to have all kinds of neat 6 cylinder stuff......unfortunately that was about 35 years ago though, LOL. Don't know if there's any 6 cylinder specialists around anymore that do cams, headers, manifolds, heads, modifiable (is that a word?) quality tuners, etc. Keep on tinkering!

Strongjeff 06-13-2013 03:46 PM

Re: any benefit to ported TB + TBS?
 
Quote:

Originally Posted by jeepgcoman (Post 841050)
Looks like that V-6 moves that 5000 lb. slug WK along pretty well. A long time ago I used to mess with the 6's, and most of them have quite a bit of potential, if you can find the parts to build them. Don't know if they're still around, but there used to be a place called Clifford Research, and they used to have all kinds of neat 6 cylinder stuff......unfortunately that was about 35 years ago though, LOL. Don't know if there's any 6 cylinder specialists around anymore that do cams, headers, manifolds, heads, modifiable (is that a word?) quality tuners, etc. Keep on tinkering!


lol,i had her weighed, she came in at 4280lbs. airram has a set of race ported and race prepped heads for this thing. it gots jba headers on it too


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