5.9 Magnum Dyno - Cam and Intake

[Jordan Townsend]

Hey guys, thought you might find this interesting. Here's some dyno results for my 1998 Grand Cherokee 5.9.

1. Lowest curve is the baseline run (stock other than k/n intake and cat back)

2. Middle curve is after intake manifold swap and headers (converted an rpm airgap, basically making a hughes copy)

3. Highest curve is after swapping stock cam for a 222/226 0.545/0.555 110 LSA unit from hughes.

Although the total power isn't very high. The gains sure are noticeable. Engine has 201k miles and runs so sweet. I've probably made over 60 dyno pulls on this poor thing and it just loves it.

Next step will be heads. Maybe some day they'll be some good ones in stock somewhere...

 

[Davezilla]

Very nice.
Do you have any more pictures of the intake modification that you would be willing to share?

 

[Jordan Townsend]

Very nice.
Do you have any more pictures of the intake modification that you would be willing to share?

I can take some for you, I didn't get many while making it. But here's a couple more on my phone. It was fairly easy, although didn't save much $, but hughes intake was backorder and I'm impatient.

 

[autoxcuda]

Hey guys, thought you might find this interesting. Here's some dyno results for my 1998 Grand Cherokee 5.9.

1. Lowest curve is the baseline run (stock other than k/n intake and cat back)

2. Middle curve is after intake manifold swap and headers (converted an rpm airgap, basically making a hughes copy)

3. Highest curve is after swapping stock cam for a 222/226 0.545/0.555 110 LSA unit from hughes.

Although the total power isn't very high. The gains sure are noticeable. Engine has 201k miles and runs so sweet. I've probably made over 60 dyno pulls on this poor thing and it just loves it.

Next step will be heads. Maybe some day they'll be some good ones in stock somewhere...

View attachment 1715864908

View attachment 1715864910

Look like those were done on a DynoJet wheel dyno, correct?

Do you have any conversion to flywheel HP and Torque for those numbers?

 

[Jordan Townsend]

Look like those were done on a DynoJet wheel dyno, correct?

Do you have any conversion to flywheel HP and Torque for those numbers?

That's correct. I usually shy away from converting numbers to potential crankshaft values as it's very arbitrary. But, since this is a jeep with a transfercase and 31" tires. I'd probably assume 20% so the 262/311 would convert to 327.5/388.8.

But that's just a guess. Anyone is welcome to apply the correction factor of their choosing.

 

[niceolddart]

I had the factory kegger manifold on my 95 5.2 Dakota. I did a little port matching work, installed VRPs (volume reduction plates I got from a place that, pretty much, all they do is Magnum engines. It's called Utawsome Performance, in Utah of course. The guy who develops this stuff for Magnum engines, Marty, is a very knowledgeable & good guy. Check them out.) a lifter valley plate, that keeps the hot oil from splashing on the bottom of the intake, installed the Hughes plenum plate, & the mildest cam I could run without messing with the OBD1 system this truck had, & man this thing woke up. OBD2 systems are far more forgiving/adjustable with a tune. Some say the kegger manifold is no good, maybe for high RPMs, (over 6000) but what a torque monster it can be with a little modification. Check Utawsome out when you get a chance. I was very happy with them

 

[Jordan Townsend]

I had the factory kegger manifold on my 95 5.2 Dakota. I did a little port matching work, installed VRPs (volume reduction plates I got from a place that, pretty much, all they do is Magnum engines. It's called Utawsome Performance, in Utah of course. The guy who develops this stuff for Magnum engines, Marty, is a very knowledgeable & good guy. Check them out.) a lifter valley plate, that keeps the hot oil from splashing on the bottom of the intake, installed the Hughes plenum plate, & the mildest cam I could run without messing with the OBD1 system this truck had, & man this thing woke up. OBD2 systems are far more forgiving/adjustable with a tune. Some say the kegger manifold is no good, maybe for high RPMs, (over 6000) but what a torque monster it can be with a little modification. Check Utawsome out when you get a chance. I was very happy with them

Thanks for the heads up. UTAwesome does some cool stuff and nice kegger mods...but personally, I don't care for the kegger. I much prefer the air gap dual plane or even a victor Jr single plane. Don't get me wrong, the off idle torque of the kegger is impressive, but north of say 4k it really struggles, even trimmed and ported runners (from the testing I've seen).

I also like an engine that rust up to 6k+ and don't mind a decent stall and low gears...

 

[autoxcuda]

Jordan, are your head totally stock?

No porting or cleanup?

 

[niceolddart]

Thanks for the heads up. UTAwesome does some cool stuff and nice kegger mods...but personally, I don't care for the kegger. I much prefer the air gap dual plane or even a victor Jr single plane. Don't get me wrong, the off idle torque of the kegger is impressive, but north of say 4k it really struggles, even trimmed and ported runners (from the testing I've seen).

I also like an engine that rust up to 6k+ and don't mind a decent stall and low gears...

I fully understand your preference. I'm glad you know about Utawsome though. If you're looking for anything Magnum related, they are super helpful & Marty really knows what works on these engines, it's all he does. Just check them out before you buy anything, & ask him. He will know the answers to any questions you may have. From your manifold machining pix, it looks like you know your stuff. Good luck. PS If that's a factory GC with the 5.9, (has the vents on the hood?) it's pretty rare. I've only seen 2 or three in my life & I think they're one year only. Very cool Jeep.

 

[Jordan Townsend]

Jordan, are your head totally stock?

No porting or cleanup?

Yes, totally stock. Nothing but a valve spring swap.

 

[Jordan Townsend]

I fully understand your preference. I'm glad you know about Utawsome though. If you're looking for anything Magnum related, they are super helpful & Marty really knows what works on these engines, it's all he does. Just check them out before you buy anything, & ask him. He will know the answers to any questions you may have. From your manifold machining pix, it looks like you know your stuff. Good luck. PS If that's a factory GC with the 5.9, (has the vents on the hood?) it's pretty rare. I've only seen 2 or three in my life & I think they're one year only. Very cool Jeep.

I'll definitely give him a shout. Yes, it's the factory 5.9 ZJ with hood vents. I got it for a steal when i was looking for a drive train for my cj7. Now that I have it, I like the grand way too much to part it out so now it's my daily driver.

 

[DionR]

Engine Masters did a test with some UTAwesome parts on a 5.9 crate motor. The modded beer barrel didn't peak as well as the AG, but seemed like a nice setup if someone wanted to stick to a BB intake.

That's correct. I usually shy away from converting numbers to potential crankshaft values as it's very arbitrary. But, since this is a jeep with a transfercase and 31" tires. I'd probably assume 20% so the 262/311 would convert to 327.5/388.8.

But that's just a guess. Anyone is welcome to apply the correction factor of their choosing.

Based on their numbers, I think your drivetrain losses are more than 20%. Pretty sure their cam was smaller and I think they were over 350 with the AG and headers. I agree that it's just a guess though, not suggesting you are wrong.