JM fab smim questions

[92awddsm]

I was wondering who was using the JM Fabrication sheet metal intake manifold? How well does it perform at the track and in occasion daily driving? I remember a while back, there was a thread with flow comparisons between several smim's but a quick search didnt show the thread. If anyone remembers it off the top of their head, please post the link. I was going to get the magnus but was curious about the JM and wanted to see and hear some feedback before I made my purchase. Thanks

Keith

 

[sweet97]

I would like to know also as I bought one and it's on the car but the car isn't on the road yet since I live in central, NY.
I searched and could find nothing with actual numbers so I took a chance. Jim had his best time with stock intake and head/cams pick up .4 and 5mph. If that is true I should be good for .8 and 10mph though i doubt that. There does not sem to be even one before and after dyno or trck run. Mark

 

[1SloColt]

A friend went from an extrude honed 1g manifold to a JM fab manifold. His logs are identical at 30psi with the 1g manifold compared to 24psi on the JM fab manifold. I say its a 40hp increase over the extrude honed 1g. Couple big cars have switched from magnus to JM manifold and picked up some good topend. The welds are strong too. I've seen one balloon from preignition without breaking the welds.

 

[92awddsm]

I was just intrigued by them when I saw one. It looks to be very good quality, mostly press bent with very few welds, velocity stacks, a tapered plenum design and cheaper than the magnus but very similar in design. If it works as well as a magnus, why not get it instead? That would leave me with more $ for other parts.

 

[arash15]

I was just intrigued by them when I saw one. It looks to be very good quality, mostly press bent with very few welds, velocity stacks, a tapered plenum design and cheaper than the magnus but very similar in design. If it works as well as a magnus, why not get it instead? That would leave me with more $ for other parts.

do it!!!! i would

 

[1SloColt]

If it works as well as a magnus, why not get it instead?

Must have missed my post. It IS working better than the magnus.

 

[sweet97]

You changed from a Magnus to a JM? Why? Since you have no numbers to back up it's better what makes you feel the JM is better than the Magnus? How much low speed driving, like in city, is lost/responsiveness? You felt it pulled harder at high rpm's? Like what range would you say it was better?
Man I sure wish we had some numbers to work with! Thanks, mark

 

[Reese92tsi]

Does this intake move the TB toward the battery like the other ones or does it only lower the TB

 

[sweet97]

Both. A 5" wide Honda battery solved that nicely leaving all there except for the plastic case. Very clean install. I think I have a pic I could send if you send me your email address. [email protected]

 

[92awddsm]

Does this intake move the TB toward the battery like the other ones or does it only lower the TB

Yes, it moves the tb just like all the others. A honda battery works fine or you could relocate yours to the trunk like I did. You will also have to modify your uicp for the repositioned throttle body.

Direct quote from JM Fab " These manifolds are designed for DSM's with eliminated EGR. Some modifications to your coil pack mounts, and upper intercooler pipes may be needed, as this manifold sits down alot lower then stock. If using the Accufab and other aftermarket throttle bodies, please note that the throttle cable and TPS sensors may need modifying."

http://www.jmfabrications.com/dsm.html

 

[1SloColt]

You changed from a Magnus to a JM? Why? Since you have no numbers to back up it's better what makes you feel the JM is better than the Magnus? How much low speed driving, like in city, is lost/responsiveness? You felt it pulled harder at high rpm's? Like what range would you say it was better?
Man I sure wish we had some numbers to work with! Thanks, mark

Another one who doesn't read all the posts. I never switched manifolds, some big companies did who have fast DSMs, i.e. turbotrix. They gained 33whp over the magnus by switching to the JM on their track car. Is that definitive enough for ya? The magnus is a proven manifold and works great. The JM manifold is proven as well. To be honest if you are making around 450 or so I doubt one would be that much better than the other. I suppose when you start making +600 and rev to 10k rpm is where you'll see one manifold shine over the other.

 

[sweet97]

A friend went from an extrude honed 1g manifold to a JM fab manifold. His logs are identical at 30psi with the 1g manifold compared to 24psi on the JM fab manifold. I say its a 40hp increase over the extrude honed 1g. Couple big cars have switched from magnus to JM manifold and picked up some good topend. The welds are strong too. I've seen one balloon from preignition without breaking the welds.

Is this the post I missed where turbotrix got the big gains over the Magnus that I missed? Must have been the line where "Couple big cars have switched from magnus to JM manifold and picked up some good top end too". I'm sorry and apologize that I'm another one who doesn't read the preceding posts also. I will be more diligent in the future! Thanks, Mark

 

[sweet97]

Must have missed my post. It IS working better than the magnus.

Here's where you told another guy he missed one of your posts also. Honestly it's tough to read between the lines and understand what you are trying to express, my fault again, my apologies again, also! Mark

 

[Dark_Horse]

I ordered a 1G JM Fab SMIM 2 days ago...I'll log a few pulls before install and a few after and post up the difference in airflow...Don't have the funds to do dyno pulls.
Will probably be a few weeks before the 1G -vs- JM Fab intake manifold test happens though.

1Slocolt - where did you see the info on the JM Fab picking up 33whp over the Magnus? Do you have a link?

Thanks

 

[92awddsm]

Must have missed my post. It IS working better than the magnus.

No I didnt miss it. If it worked better on your friend's cars, good for them. Mine isnt a big name car(unless you consider Team Trinity a big name) and Im not running a huge turbo either. I am mainly trying to increase the efficiency of my my turbo and extend the useable rpm's. My main concern is cost vs performance.

Also, what you quoted me on was more of a statement than a question. All Ive heard about the JM has been good but at the same time, I havent heard much at all about it.

Will you friend be at the GMU meet? I will be one of the parking attendants, judges, and whatever else. I would like to see someone there with a JM IM so I can question them about it first hand. And then it (Magnus or JM) will be ordered the following Monday (3-13). I will be going to the track the 19th with stock intake and hopefully the 26th with new intake to get some comparison. Both track days will start on pump gas and 25psi and end up with race gas and 32+ psi, given that I can get some traction and my engine lasts through the first track day. And for the record, my stock im is stock. No porting or extrude hone. It is the same as what you would pull off at the local junkyard.

 

[1SloColt]

1Slocolt - where did you see the info on the JM Fab picking up 33whp over the Magnus? Do you have a link?

Thanks

This was on Dsmtalk a while back in a thread when people were comparing manifolds. I might be able to find the link for you.

No I didnt miss it. If it worked better on your friend's cars, good for them. Mine isnt a big name car(unless you consider Team Trinity a big name) and Im not running a huge turbo either. I am mainly trying to increase the efficiency of my my turbo and extend the useable rpm's. My main concern is cost vs performance.

I don't consider Team Trinity a big name. Seem to be some decent guys among yall though. I know Liam, Jerry, and Chris Lyons personally.

Also, what you quoted me on was more of a statement than a question. All Ive heard about the JM has been good but at the same time, I havent heard much at all about it.

Will you friend be at the GMU meet? I will be one of the parking attendants, judges, and whatever else. I would like to see someone there with a JM IM so I can question them about it first hand. And then it (Magnus or JM) will be ordered the following Monday (3-13). I will be going to the track the 19th with stock intake and hopefully the 26th with new intake to get some comparison. Both track days will start on pump gas and 25psi and end up with race gas and 32+ psi, given that I can get some traction and my engine lasts through the first track day. And for the record, my stock im is stock. No porting or extrude hone. It is the same as what you would pull off at the local junkyard.

Dave will be at the GMU meet, but I'm not sure if he's bringing his car. Like I said, he's flowing the same amount of air and using the same amount of fuel at 24psi on the JM manifold compared to the extruded honed 1g manifold at 30psi. The only two comparisons I've seen between the JM manifold and the magnus manifold is what turbotrix has done and another company that I can't pull off the top of my head. I'll see if I can scrounge up the info.

 

[92awddsm]

Dave will be at the GMU meet, but I'm not sure if he's bringing his car. Like I said, he's flowing the same amount of air and using the same amount of fuel at 24psi on the JM manifold compared to the extruded honed 1g manifold at 30psi. The only two comparisons I've seen between the JM manifold and the magnus manifold is what turbotrix has done and another company that I can't pull off the top of my head. I'll see if I can scrounge up the info.

I found out yesterday that it was Dave you were talking about. I know Dave as well and didnt realize that he had swapped out the extrude honed 1g for the JM. Thanks.

 

[TSisleeper]

who sells this JM FAB intake/ where can I get one, I was gonna buy a magnus but now I think I'll make a different choice.

 

[GSTac]

who sells this JM FAB intake/ where can I get one, I was gonna buy a magnus but now I think I'll make a different choice.

www.jmfabrications.com

 

[danielbui]

slowboy

 

[mirkoelek]

I wish there will be a small company that will make a new manifold that would work way better than these verrrrry expencive freaking peace of ...... I dont see why one aftermarket manifold be more than $300. Price for one magnus manifold is just funny to me. the JMF sounds better but still expencive...

 

[GVR4592]

I wish there will be a small company that will make a new manifold that would work way better than these verrrrry expencive freaking peace of ...... I dont see why one aftermarket manifold be more than $300. Price for one magnus manifold is just funny to me. the JMF sounds better but still expencive...

If you had any idea the amount of time it takes to make the manifold you would understand why they cost what they do.

 

[mirkoelek]

If you had any idea the amount of time it takes to make the manifold you would understand why they cost what they do.

how would you know?

 

[GVR4592]

I've done a lot of welding and fabricating and I own a business. I know what goes into these manifolds and I know the costs of running a business. The tools alone justify the cost. The people building and selling these manifolds aren't getting rich.
If you think it's so easy, go rent a welder and a bandsaw for a weekend and give it hell.

 

[PokinatchaPunk]

If you think it's so easy, go rent a welder and a bandsaw for a weekend and give it hell.

Screw that....I'm gonna get some cardboard, crazy glue and some duct tape and I'll make one hell of a manifold.

jk

It's funny how I see people actually try that. They make a box with four runners and expect to be just as good.