I6 vs v8 - JeepForum.com
 
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post #1 of 14 Old 09-21-2014, 07:43 AM Thread Starter
jeepjunkie97
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I6 vs v8

Just something to talk about. If your stock 4.0 died would you put a 4.7 stroker with a turbo in or a run of the mill 300 hp v8?

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post #2 of 14 Old 09-21-2014, 07:45 AM
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There's no replacement for displacement.

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post #3 of 14 Old 09-22-2014, 10:02 PM
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You're an American, right?

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post #4 of 14 Old 09-23-2014, 01:34 PM Thread Starter
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Originally Posted by premo
You're an American, right?
Well if you want to being my nationality into I'll throw a nhra nitro engine into it (;
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post #5 of 14 Old 09-23-2014, 01:55 PM
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You know what to do

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post #6 of 14 Old 09-23-2014, 02:25 PM
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Technically depening on how large the V8 is, Im willing to bet the turbo 6 would have a ton more torque... check out 505 performance.Their turbo kit adds 92 rear wheel horsepower and 104 rear wheel torque. Adjusting for the same percentage of losses that puts it at 318hp at the crank and about 365 torque this is without their stroker motor, just on a stock 4.0
I would also consider a cummins 4bt.

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post #7 of 14 Old 09-23-2014, 02:39 PM
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that's nice but its really only relative to RPM range and what the intended purpose for the vehicle is. I would never in a million years put a turbo on my jeep. it only see's rocks at slow speed. If one was muddin' or going for speed maybe it would make sense.

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post #8 of 14 Old 09-23-2014, 03:31 PM
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This is interesting as I was just researching comparisons between the Ford 300 I6 and the Ford 302 V8. Pretty apples to apples comparison really, all things considered. They have damn near identical displacements, they were made during the same era by the same manufacturer, and they were both available in carbureted and fuel injected versions. For a Jeep, I'd stay with the inline 6.

I'd say that as a rule of thumb, for a given displacement, having fewer, larger pistons will give you more low-end power compared to an engine with smaller pistons but more of them to give equal displacement. So if you're consistently needing power above 3000 RPM, a V8 would be much better suited. However, for climbing or pulling where you need power in that 1500-3000 range, the I6 is hard to beat.

A ton of guys do V8 swaps on their Jeeps and have gobs of torque. Typically though, these V8s are much higher displacement as well. That Ford 300 (4.9L) is one of the largest engines for a large scale production I6. Now, if anyone made a 5.7-6.0L I6, I don't think there would be much question what swap I would do.

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post #9 of 14 Old 09-23-2014, 03:59 PM
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Hell if I had a Jeep worth fixing up (tweaked uni-body) I would slap a turbo on there right now!

I hear people always say never turbo a jeep because its not a race car or mud slinging monster truck. . . Its a jeep, the I6 has an abundance of torque at low speed, I bet 95% of the people never use all the power the I6 already has to offer when doing slow speed technical stuff. At that point why do you need a 4.7, or a 5.0 I6, you will never use all that power either, might as well keep it stock right?

Most people I read about are looking for that extra bit of torque to keep them moving down the freeway, or through those canyons with 33"-35" tires and tall gearing because they don't want to spin 3K rpm at 65-70mph. Very rarely do I read about someone wanting to stroke or swap a V8 so they can get through that rocky section faster.

To me a turbo would be a great addition for any Jeep. The I6 has plenty of power already for low speed crawling, the only thing it is lacking is power up top for highway cruising and canyon passing.


But that's just my opinion. . .



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Originally Posted by premo View Post
that's nice but its really only relative to RPM range and what the intended purpose for the vehicle is. I would never in a million years put a turbo on my jeep. it only see's rocks at slow speed. If one was muddin' or going for speed maybe it would make sense.

Turbo is relative to engine load, supercharger is relative to RPM.

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post #10 of 14 Old 09-23-2014, 04:22 PM
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yes, I understand how it works. I've owned, built and worked on plenty of SC/T/NA sports cars, both foreign and domestic.


its not just as easy as slapping on a turbo like you put it and have all this usable power. Unless you plan to run a smaller turbo like a T25 for example. if you plan to run much of any boost or a large turbo (like a t3/t4 for example) and put some boost down you're going to have to drop your compression down or you're going to start blowing head gaskets, snapping cranks and rods. Then with that comes turbo lag. oh yea, you'll need to run oil lines, an oil cooler. Then have your oil changed/cooked every 3k miles for all the power your getting. heaven forbid you live in the desert (like myself) and need to get some air flow across an intercooler when going slow thru the rock beds and canyons. We could get into AR trim and other stuff but what's the point


My point is that's its all relative to the application. I'm not against turbos. I'm a big fan actually. I love big turbos and big boost. It really just depends on the application. And turbos are very much relative to RPM, they just don't offer a relative TQ/HP curve like a SC.


I'll stick with my bone stock I6 and gears. I wheel with a guy in a toy with 40's and a 22r. 4 very angry gerbils maybe throwing down 90hp on propane. He does just fine with that marlin doubler. That being said, if someone offered to install a SBF/SBC of the same HP/TQ I'd take it in a heart beat. the sounds is just dandy

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post #11 of 14 Old 09-23-2014, 05:31 PM
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I completely understand all the technical details behind turbo charging a vehicle, a V8 swap would be more involved which this thread is also talking about. A stroker would be by far the easiest thing to do.

I guess I was trying to get at is a turbo will add power where I feel itís needed. Remember, we are talking about a Jeep here and only looking for a slight bump in power, we arenít looking to make a 500hp beast. Compression is already what, 8.8:1, You dont need more than 6-8psi at best so the head gaskets should be fine unless you have problems already, splitting the crank and rods isnít a an issue at these power levels. If you size your turbo properly you wonít have an issue with lag, if you donít see full boost till 2200rpm so what. Sure a turbo that spools that early might run out of steam at 300-350hp, itís a jeep. Oil lines are probably the easiest thing out of the entire system, I never ran an oil cooler so I donít know why I need one now. I do live in the desert and have spent many hours in Phoenix rush hour traffic crawling at an unbearably slow pace in 100+ degree weather with AC blasting and AITís were acceptable. This is comparing my Turbo charged 97 Camaro.

Iím not trying to be argumentative but itís really not as bad as you make it out to be. Would it be easy, no, but considering the fabrication skills and ability of the people on this site to learn, I donít think it would be that hard either.

I think one of the problems is the word ďturboĒ, everyone that hears the word turbo automatically assumes itís a race car thing. . .

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post #12 of 14 Old 09-23-2014, 05:51 PM
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Oh I know, I wasn't trying to be argumentative either. Just trying to convey that it's really all about the end user's application.

I'm sure there's plenty of people here that can handle the task..I just don't think the means justify the ends. Again, all depends on what you're doing with it at the end of the day. I just feel there's better, easier and more cost effective options to make small power gains. Like a throttle body spacer. JK!

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post #13 of 14 Old 09-23-2014, 06:55 PM
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Quote:
Originally Posted by Alcancia View Post
This is interesting as I was just researching comparisons between the Ford 300 I6 and the Ford 302 V8. Pretty apples to apples comparison really, all things considered. They have damn near identical displacements, they were made during the same era by the same manufacturer, and they were both available in carbureted and fuel injected versions. For a Jeep, I'd stay with the inline 6.

I'd say that as a rule of thumb, for a given displacement, having fewer, larger pistons will give you more low-end power compared to an engine with smaller pistons but more of them to give equal displacement. So if you're consistently needing power above 3000 RPM, a V8 would be much better suited. However, for climbing or pulling where you need power in that 1500-3000 range, the I6 is hard to beat.

A ton of guys do V8 swaps on their Jeeps and have gobs of torque. Typically though, these V8s are much higher displacement as well. That Ford 300 (4.9L) is one of the largest engines for a large scale production I6. Now, if anyone made a 5.7-6.0L I6, I don't think there would be much question what swap I would do.
Very well said. I own a 300 I6 truck and have owned a couple 302 foxbody mustangs, very good comparison. Both very effective, both with different strongsuits.

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post #14 of 14 Old 09-24-2014, 06:36 AM
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If my 2000's engine waits until I have a garage and money before it tosses a piston skirt, I'd be very inclined to go with a stroker. But I have a thing for I6 engines ... would rather have one than a V8!

I think a 4.7 stroker with a small turbo would be pretty nice for low end and mid range torque.

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