Cheapo Cherry Bomb Retrofit

FarmDiesel · **Joined:** Thu Sep 15, 2005 8:49 am **Posts:** 132

Well, 2 weeks ago, I disconnected the exhaust at the flange in front of the muffler and drove 2 miles to listen to how the exhaust would likely sound if straight-piped. Didn't like it.

I looked into the Aero-turbine. Liked it. Looked at the price. Didn't like it.

I looked at various generic turbo mufflers. Didn't like 'em.

I looked at name brand mufflers (Magnaflow, etc.). Was ambivalent.

I looked at a $12 cherry bomb glasspack. Was intrigued. 2.5" in, 2.5" out. Bought it, and $4 of 2.5" muffler tubing. Last night, after about 30 minutes of cutting and welding, I cut out the stock muffler, welded the cherry bomb to the bolt-on flange formerly attached to the front of the stocker, and made a joint to slide on the rear of the tailpipe. So the replacement muffler I've installed bolts on in front, like a stocker, and slides on in the rear, over the stock tail pipe that goes over the rear axle (it's attached with 2 muffler clamps. Ok, so only one is necessary...but I like redundancy).

First reports: I cannot get EGTs to exceed 900-920 degrees. That is compared to reaching 1050 or so when floored on an incline under similar climactic conditions. At high power settings, EGTs are dramatically lower. Under normal cruising conditions, EGTs look to be mildly better (maybe 20-80 degrees. I'm still making my initial observations).

Sound (outside): At idle, a nice deep bass. Almost sounds like a V-8 diesel. I'm very pleased. Above idle, I haven't had the opportunity to check it out very much. From what I heard, sounds pretty slick.

Sound (inside): At idle, very little noticeable change inside. Can hear some of the bass rumble. Cruising, have gone from hearing only engine/tire/wind noise to hearing a slight exhaust note in the background (a slight increase in noise, overall, but no drone and nothing unpleasant or really noticeable unless you're really looking for it). Accelerating: much more pleasant sound. Step on it: A really unique WHOOOOOOSHH sound when the turbo spools up. Unlike anything I've ever heard from an engine. If you lower the windows, you can hear the turbo purring a bit as well.

So far, I'm quite pleased with my $16 investment. I'll try to report if there are any changes in mileage, or if my initial EGT observations hold true.

wenied · **Joined:** Wed Dec 21, 2005 4:01 pm **Posts:** 107

I'm planning on having a glass pack installed on mine as soon as i get a chance to do it. The shop will do it for about 70 dollars. Wish I could weld!!
lol

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Where did you say you installed your pyrometer? Post or Pre-Turbo? Also, would love to know what EGT's are at idle, after a normal traffic run. 600-650 degrees F ?

FarmDiesel wrote:

Well, 2 weeks ago, I disconnected the exhaust at the flange in front of the muffler and drove 2 miles to listen to how the exhaust would likely sound if straight-piped. Didn't like it.

I looked into the Aero-turbine. Liked it. Looked at the price. Didn't like it.

I looked at various generic turbo mufflers. Didn't like 'em.

I looked at name brand mufflers (Magnaflow, etc.). Was ambivalent.

I looked at a $12 cherry bomb glasspack. Was intrigued. 2.5" in, 2.5" out. Bought it, and $4 of 2.5" muffler tubing. Last night, after about 30 minutes of cutting and welding, I cut out the stock muffler, welded the cherry bomb to the bolt-on flange formerly attached to the front of the stocker, and made a joint to slide on the rear of the tailpipe. So the replacement muffler I've installed bolts on in front, like a stocker, and slides on in the rear, over the stock tail pipe that goes over the rear axle (it's attached with 2 muffler clamps. Ok, so only one is necessary...but I like redundancy).

First reports: I cannot get EGTs to exceed 900-920 degrees. That is compared to reaching 1050 or so when floored on an incline under similar climactic conditions. At high power settings, EGTs are dramatically lower. Under normal cruising conditions, EGTs look to be mildly better (maybe 20-80 degrees. I'm still making my initial observations).

Sound (outside): At idle, a nice deep bass. Almost sounds like a V-8 diesel. I'm very pleased. Above idle, I haven't had the opportunity to check it out very much. From what I heard, sounds pretty slick.

Sound (inside): At idle, very little noticeable change inside. Can hear some of the bass rumble. Cruising, have gone from hearing only engine/tire/wind noise to hearing a slight exhaust note in the background (a slight increase in noise, overall, but no drone and nothing unpleasant or really noticeable unless you're really looking for it). Accelerating: much more pleasant sound. Step on it: A really unique WHOOOOOOSHH sound when the turbo spools up. Unlike anything I've ever heard from an engine. If you lower the windows, you can hear the turbo purring a bit as well.

So far, I'm quite pleased with my $16 investment. I'll try to report if there are any changes in mileage, or if my initial EGT observations hold true.

Katmandu · **Posted:** Sat Jan 21, 2006 12:23 pm

FarmDiesel wrote:

So far, I'm quite pleased with my $16 investment. I'll try to report if there are any changes in mileage, or if my initial EGT observations hold true.

Has it changed your MPG any ??

FarmDiesel · **Joined:** Thu Sep 15, 2005 8:49 am **Posts:** 132

EGTs are difficult to report. Running at 70mph, they tend to stay aroudn 780. Speed up to 75, and they drop to just over 700. I can't explain that one...maybe an increase in boost or something? The airflow difference through the intercooler cannot be enough to change things.

Running around town at a steady speed, it is in the mid 600s. Accelerating from 0-40 or so, it'll go up to 800, and then back off slowly. And that's accelerating very calmly.

If you're running along at 50 and let off the throttle to coast up to a light, the EGTs drop 2-300 degrees in about 10 seconds, as you get engine braking.

The EGTs have definitely dropped since the mufflerectomy. Hard to say by how much. Peak EGTs, at full throttle, uphill, at 60mph or so have also dropped significantly...as in 150-200 degrees.

All of this assumes a warmed-up engine.

retmil46 · **Posted:** Mon Jan 23, 2006 12:44 pm

FarmDiesel wrote:

EGTs are difficult to report. Running at 70mph, they tend to stay aroudn 780. Speed up to 75, and they drop to just over 700. I can't explain that one...maybe an increase in boost or something? The airflow difference through the intercooler cannot be enough to change things.

Running around town at a steady speed, it is in the mid 600s. Accelerating from 0-40 or so, it'll go up to 800, and then back off slowly. And that's accelerating very calmly.

If you're running along at 50 and let off the throttle to coast up to a light, the EGTs drop 2-300 degrees in about 10 seconds, as you get engine braking.

The EGTs have definitely dropped since the mufflerectomy. Hard to say by how much. Peak EGTs, at full throttle, uphill, at 60mph or so have also dropped significantly...as in 150-200 degrees.

All of this assumes a warmed-up engine.

You know, on my trip to Texas, I could swear that the beast did better on MPG when running at 70 to 75 than it did when I had to slow down to 65 or below for various reasons. This beast hits it's max HP supposedly somewhere in the low to mid 2000's for rpm.

I agree, it's hard to explain. Perhaps oldnavy or others with more diesel experience might be able to explain this EGT/MPG oddity. Perhaps with the way this engine is set up and programmed, we've found an unknown and/or unintentional sweet spot in the operating curve.

I have heard a couple of related stories from guys in the service dept of people that have run their CRD's in certain states out west, where the daytime speed limit is basically nonexistent, of running at upwards of 90 mph and still getting upwards of 30 mpg. With what i saw on my trip with the Aero Turbine installed, and what you're seeing for EGT's, perhaps these stories aren't as full of B.S. as I thought.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Thanks for the EGT info... its good to know how our CRD's are running before major mods. I'm assuming these temps are pre-turbo measurements.

oldnavy · **Posted:** Mon Jan 23, 2006 10:12 pm

That may be why we are doing 31 mpg with cruise set at 73 mph (I have Flowmaster 40) and run 50 cetane B10 fuel.

Ripple · **Posted:** Tue Jan 24, 2006 10:02 pm

I can't get the tranny to shift into fifth until ~68 MPH, warmed up. under that it runs in 4th gear (unless i kick it up over 70 and then slow down to about 60). that might have somthing to do with the high speed-economy increase.

good post on the glass pack, could you possible get a sound clip?

FarmDiesel · **Joined:** Thu Sep 15, 2005 8:49 am **Posts:** 132

Every CRD I've seen, including my own, shifts into 5th, locked torque converter, at 58mph, and will stay there down to 55mph after it's locked in. The 68mph is a weird thing. I wonder if that's a reflash issue. It'll stay locked in 4th (the lower OD) down to 50mph. Under 50, it's unlocked torque converter unless you lock out OD (based on my observations, I think).

I don't have a good sound recording method...suggestions?

wenied · **Joined:** Wed Dec 21, 2005 4:01 pm **Posts:** 107

Actually my CRD shifts into 5th at 64mph every time.

retmil46 · **Posted:** Wed Jan 25, 2006 12:32 pm

FarmDiesel wrote:

Every CRD I've seen, including my own, shifts into 5th, locked torque converter, at 58mph, and will stay there down to 55mph after it's locked in. The 68mph is a weird thing. I wonder if that's a reflash issue. It'll stay locked in 4th (the lower OD) down to 50mph. Under 50, it's unlocked torque converter unless you lock out OD (based on my observations, I think).

I don't have a good sound recording method...suggestions?

Same shift pattern on mine.

n3qik · **Posted:** Wed Jan 25, 2006 9:09 pm

Well I am going to be differant, my CRD locks up at 51 MPH and unlocks at 48 MPH.

It has lattest flashes and second EGR. Also gutted cat with stock muffler. Gettting 18.5 to 19.5 MPG with B20.

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Ken,

Didn't you install a boost gauge a while back on your CRD? A couple of us are trying to puzzle out why greiswig is seeing a P0299 code, when he has his EGR supply blocked off with a plate. He also has a P0401, but that should be there. Other than a leak in the turbo plumbing to the intake, it seems puzzling. If you have a boost gauge, what are the normal pressure readings for idle, 30-40 mph and highway speeds, say 65-75 mph? Have you ever noticed any fluctuations on your gauge (if it was you that put the gauge in) that might look like a leak somewhere in the turbo boost plumbing?

oldnavy · **Posted:** Wed Jan 25, 2006 10:18 pm

n3qik wrote:

Well I am going to be differant, my CRD locks up at 51 MPH and unlocks at 48 MPH.

It has lattest flashes and second EGR. Also gutted cat with stock muffler. Gettting 18.5 to 19.5 MPG with B20.

Should have left the cat alone and replaced the muffler for a bigger difference in turbo spool and EGT's.

I guess I need to check and see just where the wife's CRD lock's and unlocks next time I go get fuel for her.

Ripple · **Posted:** Sat Jan 28, 2006 7:39 pm

this post inspired me to just install a muffler and stop procrastinating. see my post on jeep forum

spoonplugger1 · **Posted:** Sun Jan 29, 2006 1:47 am

One possible reason for the decrease in exhaust temp is that your using less fuel per cylinder at the speeds you were looking at, therefore less temperature. HP is torque X rpm / 5252. our torque maxes at 1800 rpm but HP continues to climb because the torque rolls off slower than the difference in rpm increase. In essence the engine uses less fuel per stroke because the engine rpm is making up for need for HP to do the same work, but the amount of times that the engine injects that smaller amount of fuel has also gone up with the increase in rpm so things don't change much MPG wise for a small window in our normal freeway operating level. As you exceed this range the fuel probably ceases rolling off as drag and other loads become more prevalent and as before torque is not rolling off as fast as the percentage difference in increased rpm. Now we have increased fuel delivery overall and increased rpm which means MPG take a noticable hit.
Used to be able to show this better with visual aids superimposing the torque curve with the HP curve, than reinforcing it with a dyno presentation where we could monitor fuel usage levels on the newer engine or simple fuel rack positions on the older style engines.

n3qik · **Posted:** Fri Feb 03, 2006 8:46 pm

Ranger1 wrote:

Ken,

Didn't you install a boost gauge a while back on your CRD? A couple of us are trying to puzzle out why greiswig is seeing a P0299 code, when he has his EGR supply blocked off with a plate. He also has a P0401, but that should be there. Other than a leak in the turbo plumbing to the intake, it seems puzzling. If you have a boost gauge, what are the normal pressure readings for idle, 30-40 mph and highway speeds, say 65-75 mph? Have you ever noticed any fluctuations on your gauge (if it was you that put the gauge in) that might look like a leak somewhere in the turbo boost plumbing?

Yep that is me, I will check next time out. I am using a non-dampend gauge and at times the gauge bounce a lot.

oldnavy wrote:

Should have left the cat alone and replaced the muffler for a bigger difference in turbo spool and EGT's.

I guess I need to check and see just where the wife's CRD lock's and unlocks next time I go get fuel for her.

That may be true, but plan to do a Hush glasspack this spring

Cheapo Cherry Bomb Retrofit

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