Bolt on Power and MPG

[Topgun514]

A hot topic and equally debated back and forth. But so many debates about a specific bolt ons and little "databases" for sources.

I would love to get a list going, what you purchased/ made. Your year, engine, make, model, etc. Next- Gains if noticed or if negligable, and facts about them- whether any dyno testing was done or studies etc.


We have read JP's article
http://www.jpmagazine.com/techartic...iter_engine_myth_busting_true_lies/index.html
and yet people still say things they do get extreme power (such as 99 intake)

Lets cut to the chase and make a "database" of our trials and try to avoid to back and forth bickering. (as much as possible because I know it will occur)

The bolt ons include but are not limited to:
Chips
Exhaust
Throttle Body Spacers
Bored Throttle Bodies
K&N products
Cold Air
Snorkels
Fans
etc.


I will start:
1988 Renix Jeep Cherokee
4.0, b/a-10 tranny
Cherry Bomb Exhaust($30):
The sound is noticeable and regular starts off the line are unnoticeable in performance. Accelerating fast is still almost un-noticeable. I have noticed easier highway speeds going uphill though. Before I would have to shift to 4th at 55 but now I can go uphill depending on gradient without engine bog at 50mph. Gas mileage may have gone up 1 mpg but this is not verified.
Studies show stock exhaust is very restrictive.

 

[The Adam Blaster]

I think you should include ALL vehicle info on a list like this, year, make, model, engine+transmission and especially modifications. Without that info included, the list won't be as useful.

 

[Topgun514]

Thanks The Adam Blaster, adjusted for request.

 

[BEVAN]

Im running a 22" Magnaflow resonator in the place of the muffler, removed cat and factory header. Also have a Rustys TB spacer & K&N filter, Engine runs very smooth and throttle response is great.

 

[gasman]

1995 xj rebuilt motor at 300,000
removed clutch fan , twin electrics
99 intake
pacesetter headers
high flo cat
off road super44 magnaflow,
new flow matched injectors,
4.88 gears ,
procomp 35 x 12.50 extreem terrains

how much did i gain ? maybe 25hp,
could i feel it , yup,
off the line its got balls, but its still a tractor at heart,
mpg never really checked,, lets say it sucked
just sold it last week, and i miss it already

now what i wanna see is mods for the 3.8, gots me a new rubicon

 

[JPK]

2010 Wrangler Unlimited. Swapped out the 3.8 with 202hp and 237lbs/ft of torque at 5,000 and 4,000rpms respectively. Swapped in a 2010 MDS VVT 5.7 Hemi with 368HP and 395lbs/ft of torque at 5,800 and 4,200rpms respectively - but more torque at 1,250rpms than the 3.8 puts out max.

Gas milage dropped, but just how much is unclear since I had the Jeep lifted, tires swapped tires and axle rations changed from 4.10's to 4.88's at the same time.

According to those who run similar lifts and tires with the 3.8 - they need 5.13 or 5.34 gears - my mileage might be two to three mpg lower with the MDS VVT Hemi.

The performance improvement has to be experienced to be fully grasped.

It is loafing at all speeds unless you "let 'er eat", runs the same no matter what the load or the terrain, tows like a Suburban, sprints like a BMW.

Also, with the AEV lift that I had installed, it corners very well with little body lean and mild understeer which can be tranformed into throttle regulated mild oversteer - better than a stock JKU, which has lots of lean and lots of understeer. (I'm sure that with way too much throttle it would break into wild oversteer or just roll.) It also rides better than a Suburban.

JPK

 

[JKDetonator]

That's some bolt on!

Hey JPK, do you mind telling us what your "bolt on" set you back? I'd lover to do the exact same thing! Did you get the manual 6 SPD? :smiley_drive:

 

[JPK]

Auto for me. I'm not sure if AEV does manuals, but others do.

The range of costs runs from do it yourself with a salvage engine and with one of the kits AEV or other at maybe $10k to turn key with a 6.4 or 426 at ?. IIRC, for the 5.7 variants, Jeep Speed Shop is least expensive at about $15k turn key, the AEV at about $20k and Burnsville a bit higher than AEV.

I paid for the non-VVT swap because I didn't want to wait for the VVT from AEV, but they ran out of non-VVT new engines, so I got the VVT. I think the VVT swap is actually less money than the non-VVT because of completeness of the engine accessories or because the supplied or a less expensive A/C condenser can be used. I expected a bill for shipping and for some other custom work AEV did but we called it done with my deposit.

It isn't a "nessecary" upgrade, but damn is it nice.

JPK

 

[ox4mag]

Superchips Flashpaq for Jeep TJ/JK is an option. You can read the review here:

http://online.jpfreek.com/2010/09/22/superchips-flashpaq-for-jeep-tj-jk/

Also, I recently took the roof rack off the TJ and Grand Cherokee since they are being used a lot lately for highway usage (yes, I know they need to be in the back country and they usually are). By just taking them off I have improved my gas mileage by about 2mpg and for a TJ (and even a WK with diesel), 2mpg is a WORLD of difference.

 

[modelbuilder]

Superchips Flashpaq for Jeep TJ/JK is an option. You can read the review here:

http://online.jpfreek.com/2010/09/22/superchips-flashpaq-for-jeep-tj-jk/

Also, I recently took the roof rack off the TJ and Grand Cherokee since they are being used a lot lately for highway usage (yes, I know they need to be in the back country and they usually are). By just taking them off I have improved my gas mileage by about 2mpg and for a TJ (and even a WK with diesel), 2mpg is a WORLD of difference.

I just sold my superchips and I can say for the price vs. HP gain it's not worth the money. Superchips has never (to my knowldege) released any kind of data showing the difference between a stock ride and a "flashed" ride.

When I asked them about data they asked if I could feel it. I said I could feel that the shift points changed but I can't tell if there is more power. They said "well if you can feel it it must be working."

Bottom line...spend your money elsewhere if you want performance gain.

 

[JPK]

Auto for me. I'm not sure if AEV does manuals, but others do.

The range of costs runs from do it yourself with a salvage engine and with one of the kits AEV or other at maybe $10k to turn key with a 6.4 or 426 at ?. IIRC, for the 5.7 variants, Jeep Speed Shop is least expensive at about $15k turn key, the AEV at about $20k and Burnsville a bit higher than AEV.

I paid for the non-VVT swap because I didn't want to wait for the VVT from AEV, but they ran out of non-VVT new engines, so I got the VVT. I think the VVT swap is actually less money than the non-VVT because of completeness of the engine accessories or because the supplied or a less expensive A/C condenser can be used. I expected a bill for shipping and for some other custom work AEV did but we called it done with my deposit.

It isn't a "nessecary" upgrade, but damn is it nice.

JPK

I should add that the Hemi swap also includes a transmission swap. The new trans is the 545rfe I believe. 5 speed and it doesn't have the too tall O/D of the JK 4 spped auto. Matches the Jeep and Hemi well.

 

[alexfm]

Well, I'll throw my little upgrade into the mix as well.
First of, specs:
95 XJ
215K Miles
4.0L HO/AX-15/ NP-231

I added a FRAM AirHog air filter. The only reason I bought it was because it was cheap and I needed to fill the $25 order to get free shipping on Amazon. :snorkel: Anywho, I did notice a slight increase, but my dad did not, and he said it was all in my head. I dont have easy access to a dyno or anything like that, so I cant say for sure whether or not it did anything, but I like it. And best of all, it came with a cool sticker!

 

[The Adam Blaster]

Regarding the removal of a roof rack...
Oh, I have a '98 XJ with auto tranny and at the time I had the roof rack, it was on a 3" lift with 31" BFG M/T's - the old style ones, everything else was stock.

Anyways, I had purchased a Surco rack with no valence or anything, because it was cheap and I was looking to store my spare tire and jerry can up top and out of the way.
I was living in Windsor Ontario at the time and took a trip up to Toronto at least once a month, and with the rack on, I was getting only about 400 km per tank of gas, barely enough to get me door to door on that route.
I took the rack off, made the same trip a couple weeks later and I was able to get about 500 km from one tank.
From that point on I had pretty much decided I would never have a roof rack on a vehicle unless there were some very specific extenuating circumstances.

I will say, if anyone is on hte fence about regearing after putting a medium to large lift on their vehicle, I would say if you can at all afford it, do it!
I now have a 4.5 Rubicon Express lift with 33x12.5's on my XJ now, and had 4.56's installed about a month ago. Man, what a difference!
Very easy to hold speed on the highway, going up hills etc. And of course off the line it's night and day compared to the stock 3.55's that I replaced.
I also like the ARB I put in the front diff as well, that's another mod I won't be able to live without in the future. :elkgrin:

 

[Topgun514]

Any more takers?

 

[JPK]

I'll second the comments on the roof rack. The "roof rack" - mounts to the windshield bolts at front and body at rear - has a couple of small utility boxes mounted to it and the combo eats gas milage and range on my LJ. I run 33's with 4.10's and while I think that combo is fine w/o a roof rack, with a roof rack 4.88's would be better.

If the LJ had more room I would skip the rack and the boxes, or at least the boxes, but room is at a premium. Since I used the LJ for hunting and fishing I was frequently using the rack, so it stays on it. Now that the LJ is semi-retired (in favor of my JKU) at a hunting club until my duaghter turns 16 it will stay outfitted, rack included. But when it goes to my daughter it will loose the rack, boxes and all the gear they carry.

JPK