Are Longtubes bad for DOHC engines?

01yellercobra said:

Suck the valve seals out? Haven't heard of that one. I remember a long time ago Mac was having quality issues. I think there was slag left in the pipes that would get through the EGR and score the cylinders. I'm pretty sure they've been good for a while though.

I think it's more bang for the buck. Not everyone things the gains are worth the cost and pain to install. Kind of like cams.

Click to expand...

Black02GT said:

^^^this guy got it^^^
Good quality pipes make good power on engines that can use them. Take what you want to take from that. If your looking for a deal of HP wrong tree. Unless you can install them, gaint bitch depending on the size. If you paying... money spent elsewhere.

Sound great though, just like though cams....

If I'd do it again, fuel system, blower, done...
700 though stock manifolds and Magnaflow cats e85.
If you got the headers, put em on yourself, Cobra right of passage.
Make more now, but quickly diminishing returns w, RPM cams, compression and a **** ton of headaches. Think ahead is my only advice.

Click to expand...

Nervouswreck said:

I finally scored a set of MAC Longtubes for my Cobra and after doing some research on Stangnet and Some other places , and I’m reading some people are saying that Longtubes “suck the valve seals out” and are bad for our motors ????? Has anyone else heard this ????


Sent from my iPhone using the svtperformance.com mobile app

Click to expand...

Nervouswreck said:

I’ve done 3 Longtube jobs on these cars . I think they’re easy myself but i could see how people would think they suck


Sent from my iPhone using the svtperformance.com mobile app

Click to expand...

Nervouswreck said:

I’ve done 3 Longtube jobs on these cars . I think they’re easy myself but i could see how people would think they suck


Sent from my iPhone using the svtperformance.com mobile app

Click to expand...

01yellercobra said:

I remember a long time ago Mac was having quality issues. I think there was slag left in the pipes that would get through the EGR and score the cylinders

Click to expand...

fitforspeed said:

I had Mac long tubes on my 03, great header for the $. I think many miss the point of headers, especially on a supercharged engine. It’s not all about the horsepower gains, although I feel definitely worthwhile gains can be realized. The real advantage of full length headers is the ability the get the exhaust out of the head efficiently and thus reduce the heat backed up in the cylinders from the restrictive manifolds, especially under elevated boost from positive displacement blowers. The engine will thank you.


Sent from my iPhone using svtperformance.com

Click to expand...

fitforspeed said:

The real advantage of full length headers is the ability the get the exhaust out of the head efficiently and thus reduce the heat backed up in the cylinders from the restrictive manifolds, especially under elevated boost from positive displacement blowers. The engine will thank you.

Click to expand...

Rambro said:

If the stock manifolds were restrictive you'd see much bigger gains than 10 horsepower on 6-700 rwhp cars. Just going by what I've been reading on here all these years.

Click to expand...

Albatross said:

^^ I agree with this. It makes your engine much more efficient. You will probably see a drop in boost but will also see an increase in power/torque. It may be a slight increase but you have to think, less boost with more power=more efficient. Add some bigger injectors and a BAP to go with more air moving through the motor and the gains will increase. I added 60lb injectors and a BAP when I installed my kooks headers and saw an increase of 23hp and 86tq at the wheels. Went from 457hp/436tq to 480hp/522tq. Didn't hurt low end torque at all either. I have the before and after Dyno to prove this. This is on a non ported stock blower with a 2.8 pulley. And the sound is pure joy! Yes, they are a pain to install but any worthwhile mod is not going to be easy. As for the comment "they suck the valve seals out"... Absolutely ridiculous! Put long tubes on, go wide open throttle and you will have to surgically remove the smile from your face!

Click to expand...

Rambro said:

But then there's guys like Bdubbs who only gain ten horsepower on a tvs. Ctgreedy did a comparison a couple years ago. He had a 2.8KB at 21 psi with factory manifolds make 720, switched to kooks and gained 12 hp and around 20 ish torque. Gainz yes, but a quality set of longtubes and x pipe is over a grand. Then you almost have to do a tubular k member if you want to be able to work on them without dropping the k member. Longtubes also make it a pain to pull/install the motor from the top. I'll never be convinced that I'll "need" them at 700 rear wheel.

Click to expand...

fitforspeed said:

I had Mac long tubes on my 03, great header for the $. I think many miss the point of headers, especially on a supercharged engine. It’s not all about the horsepower gains, although I feel definitely worthwhile gains can be realized. The real advantage of full length headers is the ability the get the exhaust out of the head efficiently and thus reduce the heat backed up in the cylinders from the restrictive manifolds, especially under elevated boost from positive displacement blowers. The engine will thank you.


Sent from my iPhone using svtperformance.com

Click to expand...