Stroker vs Stock

[89 MJ]

3 hours ago, benjy_26 said:

Would it really be cheaper? 

For the price I can get a used LS, yes. 

[m2bandit]

I'm not sure what this kit comes with for reference you can look at my stoker build parts list. 
I doubt your kit comes with a bored TB and the renix TB is garbage.
will probably need larger injectors. 
The head has a lot of casting garbage to grind off. 

I'd say the biggest lesson I learned from my build was, don't do the 99+ intake $#!&. It accomplishes little and is annoying.

I say stroker ONLY if you just want a healthy motor. If you're doing it for power go LS. 
My Stoker runs amazingly but... I might toss it in my MJ. My xj can handle more skinny pedal than I have. 

Parts list
https://docs.google.com/spreadsheets/d/1xTunJzocDmT51AIPQOVKN-plp82W3o7mqS9_Ko1n_K8/edit?usp=sharing


 

[89 MJ]

8 hours ago, m2bandit said:

renix TB is garbage.

Why do you say that?

[75sv1]

I wouldn't say the RENIX TB is junk. Still, it is limited to what diameter you can bore it out to. I'd say on a stroker, 62mm is the minimum. Also, the exhaust needs to be 2.5" diameter. Some are going 3".  Also, I have a different view on the 99+ intake. Hornbrod a member on here, posted a dyno of 12hp gain. That was at the rear wheels. Some of this is that  the system needs to be equal or balanced. So, the last part you put on that corrects the flow, will be were you see the power gain. 

[89 MJ]

Noted. Thanks

[m2bandit]

6 hours ago, 75sv1 said:

I wouldn't say the RENIX TB is junk. Still, it is limited to what diameter you can bore it out to. I'd say on a stroker, 62mm is the minimum. Also, the exhaust needs to be 2.5" diameter. Some are going 3".  Also, I have a different view on the 99+ intake. Hornbrod a member on here, posted a dyno of 12hp gain. That was at the rear wheels. Some of this is that  the system needs to be equal or balanced. So, the last part you put on that corrects the flow, will be were you see the power gain. 

You have a link to those 99+ numbers? It probably helps but I doubt very much. All I've ever seen is butt dyno, aside from this link.
https://www.fourwheeler.com/how-to/engine/154-0911-jeep-4-liter-engine-myth-busting-true-lies/


The Renix TB is 52mm it is junk, it could never feed a stroker. 

[89 MJ]

21 minutes ago, m2bandit said:

The Renix TB is 52mm it is junk, it could never feed a stroker. 

Thanks. 

[75sv1]

1 hour ago, m2bandit said:

You have a link to those 99+ numbers? It probably helps but I doubt very much. All I've ever seen is butt dyno, aside from this link.
https://www.fourwheeler.com/how-to/engine/154-0911-jeep-4-liter-engine-myth-busting-true-lies/


The Renix TB is 52mm it is junk, it could never feed a stroker. 

  The HO's at stock are about the same restriction, as the RENIX. They barely feed a stock 4.0L. I think the RENIX can be bored out to 57MM and the HO to 60MM, by removing the restriction. I think the RENIX can be bored with a new butterfly to 60MM and the HO to 62mm. Yes, 60mm is not good for a stroker. 

   I have followed the 99+ intake manifold for a long time. Yes, some have lost a few ponies. Some have gained a few. I do have one on my 98 XJ, stock motor. Initially, I did not see much if any improvement. That is with a Doug Thorley header and 2.5 exhaust. I was having trouble with some of the hills on I-79 in WV. I bored out the TB to 60mm. I did not have to downshift to 3rd on those hills. I don't have the files for that dyno run. I remember Hornbrod using Neon injectors. I was using Ford 4 hole, and now have 12 hole Bosch. 

 

    Go Jeep's page:

         http://gojeep.willyshotrod.com/HowtoIntakeManifold1.htm

 

               I remember Jordache posting that info on NAXJA. I lot of ???. I don't remember him posting that he changed the regulator. 

   

[89 MJ]

35 minutes ago, 75sv1 said:

  The HO's at stock are about the same restriction, as the RENIX. They barely feed a stock 4.0L. I think the RENIX can be bored out to 57MM and the HO to 60MM, by removing the restriction. I think the RENIX can be bored with a new butterfly to 60MM and the HO to 62mm. Yes, 60mm is not good for a stroker. 

   I have followed the 99+ intake manifold for a long time. Yes, some have lost a few ponies. Some have gained a few. I do have one on my 98 XJ, stock motor. Initially, I did not see much if any improvement. That is with a Doug Thorley header and 2.5 exhaust. I was having trouble with some of the hills on I-79 in WV. I bored out the TB to 60mm. I did not have to downshift to 3rd on those hills. I don't have the files for that dyno run. I remember Hornbrod using Neon injectors. I was using Ford 4 hole, and now have 12 hole Bosch. 

 

    Go Jeep's page:

         http://gojeep.willyshotrod.com/HowtoIntakeManifold1.htm

 

               I remember Jordache posting that info on NAXJA. I lot of ???. I don't remember him posting that he changed the regulator. 

   

So an bored HO TB would be better for a Stroker than a bored Renix because it can be bored out more, correct?

[ghetdjc320]

2 hours ago, 75sv1 said:

  The HO's at stock are about the same restriction, as the RENIX. They barely feed a stock 4.0L. I think the RENIX can be bored out to 57MM and the HO to 60MM, by removing the restriction. I think the RENIX can be bored with a new butterfly to 60MM and the HO to 62mm. Yes, 60mm is not good for a stroker. 

   I have followed the 99+ intake manifold for a long time. Yes, some have lost a few ponies. Some have gained a few. I do have one on my 98 XJ, stock motor. Initially, I did not see much if any improvement. That is with a Doug Thorley header and 2.5 exhaust. I was having trouble with some of the hills on I-79 in WV. I bored out the TB to 60mm. I did not have to downshift to 3rd on those hills. I don't have the files for that dyno run. I remember Hornbrod using Neon injectors. I was using Ford 4 hole, and now have 12 hole Bosch. 

 

    Go Jeep's page:

         http://gojeep.willyshotrod.com/HowtoIntakeManifold1.htm

 

               I remember Jordache posting that info on NAXJA. I lot of ???. I don't remember him posting that he changed the regulator. 

   

I run the 99+ intake and it works well. Don’t have any dyno numbers yet but hope to get some soon. My TB was bored to 63mm since that is what the stock opening on the intake is. I got mine from Strokedjeep.com

[Jeep Driver]

3 hours ago, 89 MJ said:

So an bored HO TB would be better for a Stroker than a bored Renix because it can be bored out more, correct?

[89 MJ]

1 hour ago, Jeep Driver said:

Is that a Holley kit? Does it fit on a 4.0 intake. Oh, and I think I’m going to keep the truck, so I’m not as worried about budget anymore. 

[Eagle]

13 hours ago, 75sv1 said:

I wouldn't say the RENIX TB is junk. Still, it is limited to what diameter you can bore it out to. I'd say on a stroker, 62mm is the minimum. Also, the exhaust needs to be 2.5" diameter. Some are going 3".  Also, I have a different view on the 99+ intake. Hornbrod a member on here, posted a dyno of 12hp gain. That was at the rear wheels. Some of this is that  the system needs to be equal or balanced. So, the last part you put on that corrects the flow, will be were you see the power gain. 

 

Neither of the above statements is an absolute truism. Much depends on how the engine will be used. People build strokers to get more "power," but the reality is that the 4.0L engine was always more of a torque engine than a high-RPM horsepower engine.  A general rule is that engines with a stroke that's longer than the bore are better for low-RPM torque, while engines whose bore is greater than the stroke (so-called "over-square" engines) are more suited to revving faster and producing high-end horsepower at the expense of low-end torque.

 

The 4.0L is basically just slightly an "over-squared" engine. The stock bore is 3.88" and the stock stroke is 3.41". Even so, with the cam grind and timing selected by the factory, it builds torque quickly at low RPM and it runs out of steam above 4,000 or 4,500 RPM.

 

The 4.2L engine, which is where the strokers get their crankshafts, were true long-stroke engines. The bore was 3.75" and the stroke was 3.90". My family owned a few of them over the years. They were good engines, but they were not high-revving engines.

 

Put the 4.2L crank in a 4.0L engine with a .020 overbore and you get a bore of 3.90" and a stroke of 3.90". So it doesn't get into "over-squared" territory -- it's a balanced square. It makes for a good combination of torque and horsepower, but whether or not you "need" a bigger throttle body and/or a bigger exhaust depends completely on how it will be driven. A 4.0L engine displaces 244 cubic inches and theoretically flows 353 CFM at 5,000 RPM. A 4.6L stroker displaces 281 cubic inches and flows theoretically 407 CFM at 5,000 RPM. That's not a lot of CFM ... and how much of the time is anyone going to be driving any Jeep at 5,000 RPM?

 

I know -- from my own first-hand experience -- that increasing the exhaust behind a stock 4.0L from 2-1/4" to 2-1/2" reduces low-end torque and drops the gas mileage about 2 to 3 MPG. The increase in flow with a stroker is only 15%. That's the equivalent of accelerating from 3,000 RPM to 3,450 RPM. Does that really need a bigger exhaust and a bigger throttle body?

 

[Jeep Driver]

5 minutes ago, 89 MJ said:

Is that a Holley kit? Does it fit on a 4.0 intake. Oh, and I think I’m going to keep the truck, so I’m not as worried about budget anymore. 

 

 

If I were to do it all over again............I won't.........but..........

 

I'd use the 2 barrel Sniper on the 2.5

 

It's the way of the world now...........these 'stroker' guys have not caught up yet. 

 

Mix at the plenum, not at the valve. 

 

I know others have done it, see what you can find. 

 

 

Leave the Renix/Chryco people behind. 

[Jeep Driver]

Also- just a pic but you get the idea.

 

[89 MJ]

12 minutes ago, Jeep Driver said:

 

 

If I were to do it all over again............I won't.........but..........

 

I'd use the 2 barrel Sniper on the 2.5

 

It's the way of the world now...........these 'stroker' guys have not caught up yet. 

 

Mix at the plenum, not at the valve. 

 

I know others have done it, see what you can find. 

 

 

Leave the Renix/Chryco people behind. 

I’ll look into that. Thank you. I always appreciate your different point of view. 

[ghetdjc320]

Ok, I was probably the first to ever try the sniper route and bought the original Holley sniper in 2017 for my stroker YJ. Used a Clifford 4 barrel intake. Suffice it to say, there is such a thing as too much carb/tbi. The sniper has large injectors and can keep up with fairly high cfm requirements. On a stroker it was cutting the injector pulse down far to low to get the right afr. Since then, they have released a Jeep specific tbi/efi unit along with a nice distributor (for a 258 but fits the 242/4.0 also) for timing control. The Jeep specific unit is very likely to be too tall to fit under the hood of an xj/mj since it was made as a replacement to the old carter/bbd carbs for the 4.2s. 
     At the moment, don’t get bogged down in what injectors, throttle body etc. you will need. You need to build your engine internals first and then figure what the engine will require. It’s true, you could figure that all out now but if you want actual practical advise please tell us what kind of “stroker” you are planning to build. You have referenced a “kit” several times and we keep asking for the specs but haven’t received any. A stroker can be anything from a 4.2 mini stroker with a 232 crank to a 5.0 monster with offset ground custom crank. They will all have different requirements. Once you post up what you plan to build we can provide valuable input. Until then it’s all just speculation

[Limeyjeeper]

Having done 3 strokers this site is extremely useful. Dino Savva is a real stroker expert. He even mentions the first one I did back in the day. A bit dated but still very relevant.

 

http://jeep4.0performance.4mg.com/stroker.html

[ghetdjc320]

46 minutes ago, Limeyjeeper said:

Having done 3 strokers this site is extremely useful. Dino Savva is a real stroker expert. He even mentions the first one I did back in the day. A bit dated but still very relevant.

 

http://jeep4.0performance.4mg.com/stroker.html

Deffinitely good info. You can also see his work on angelfire with cam specs for every cam made. Jeepstrokers.com is also very helpful. 

[omega_rugal]

4 hours ago, Eagle said:

 

Neither of the above statements is an absolute truism. Much depends on how the engine will be used. People build strokers to get more "power," but the reality is that the 4.0L engine was always more of a torque engine than a high-RPM horsepower engine.  A general rule is that engines with a stroke that's longer than the bore are better for low-RPM torque, while engines whose bore is greater than the stroke (so-called "over-square" engines) are more suited to revving faster and producing high-end horsepower at the expense of low-end torque.

 

The 4.0L is basically just slightly an "over-squared" engine. The stock bore is 3.88" and the stock stroke is 3.41". Even so, with the cam grind and timing selected by the factory, it builds torque quickly at low RPM and it runs out of steam above 4,000 or 4,500 RPM.

 

The 4.2L engine, which is where the strokers get their crankshafts, were true long-stroke engines. The bore was 3.75" and the stroke was 3.90". My family owned a few of them over the years. They were good engines, but they were not high-revving engines.

 

Put the 4.2L crank in a 4.0L engine with a .020 overbore and you get a bore of 3.90" and a stroke of 3.90". So it doesn't get into "over-squared" territory -- it's a balanced square. It makes for a good combination of torque and horsepower, but whether or not you "need" a bigger throttle body and/or a bigger exhaust depends completely on how it will be driven. A 4.0L engine displaces 244 cubic inches and theoretically flows 353 CFM at 5,000 RPM. A 4.6L stroker displaces 281 cubic inches and flows theoretically 407 CFM at 5,000 RPM. That's not a lot of CFM ... and how much of the time is anyone going to be driving any Jeep at 5,000 RPM?

 

I know -- from my own first-hand experience -- that increasing the exhaust behind a stock 4.0L from 2-1/4" to 2-1/2" reduces low-end torque and drops the gas mileage about 2 to 3 MPG. The increase in flow with a stroker is only 15%. That's the equivalent of accelerating from 3,000 RPM to 3,450 RPM. Does that really need a bigger exhaust and a bigger throttle body?

 

 

nice explanation... yet people still try to revv up the 4.0...

[89 MJ]

8 hours ago, ghetdjc320 said:

Ok, I was probably the first to ever try the sniper route and bought the original Holley sniper in 2017 for my stroker YJ. Used a Clifford 4 barrel intake. Suffice it to say, there is such a thing as too much carb/tbi. The sniper has large injectors and can keep up with fairly high cfm requirements. On a stroker it was cutting the injector pulse down far to low to get the right afr. Since then, they have released a Jeep specific tbi/efi unit along with a nice distributor (for a 258 but fits the 242/4.0 also) for timing control. The Jeep specific unit is very likely to be too tall to fit under the hood of an xj/mj since it was made as a replacement to the old carter/bbd carbs for the 4.2s. 
     At the moment, don’t get bogged down in what injectors, throttle body etc. you will need. You need to build your engine internals first and then figure what the engine will require. It’s true, you could figure that all out now but if you want actual practical advise please tell us what kind of “stroker” you are planning to build. You have referenced a “kit” several times and we keep asking for the specs but haven’t received any. A stroker can be anything from a 4.2 mini stroker with a 232 crank to a 5.0 monster with offset ground custom crank. They will all have different requirements. Once you post up what you plan to build we can provide valuable input. Until then it’s all just speculation

I was told it was to make a 4.6. I do not know any other details yet. I haven’t seen him since. 

[Eagle]

3 hours ago, 89 MJ said:

I was told it was to make a 4.6. I do not know any other details yet. I haven’t seen him since. 

 

That basically suggests that it's probably for a block bored .020" over stock. A stroker built with no overbore would work out to 4.54 liters. At .020: overbore it's 4.58 liters, .040" overbore is 4.63 liters, and .060" overbore is 4.68 liters. But a .040" overbore also rounds to 4.6L ... and that doesn't tell you if it's using the 4.2 rods or the beefier 4.0L rods with special pistons.

[89 MJ]

47 minutes ago, Eagle said:

 

That basically suggests that it's probably for a block bored .020" over stock. A stroker built with no overbore would work out to 4.54 liters. At .020: overbore it's 4.58 liters, .040" overbore is 4.63 liters, and .060" overbore is 4.68 liters. But a .040" overbore also rounds to 4.6L ... and that doesn't tell you if it's using the 4.2 rods or the beefier 4.0L rods with special pistons.

Interesting. I'll let everyone know when I have more details on the kit.

[ghetdjc320]

6 hours ago, Eagle said:

 

That basically suggests that it's probably for a block bored .020" over stock. A stroker built with no overbore would work out to 4.54 liters. At .020: overbore it's 4.58 liters, .040" overbore is 4.63 liters, and .060" overbore is 4.68 liters. But a .040" overbore also rounds to 4.6L ... and that doesn't tell you if it's using the 4.2 rods or the beefier 4.0L rods with special pistons.

Exactly. It also says nothing about your compression ratio which is a key components. You need to plan and know every build spec of those engine internals as well as have all the machine work decided to move forward. Cam specs, rocker arm specs, head gasket specs, machine work specs... everything

[89 MJ]

Ok. I got more info. I was told that the cylinder walls would need to be honed and that it is a poor mans stroker kit. I could be a 4.2 and a 4.0 for $75. I would put the 4.2 crank and rods in the 4.0 block. 

 

What does everyone think?