Whats the horse power differance between stock intake manifold verse the front facing manifold on a 7m all things considered equal?
stock verse front facing manifold
- Thread starter Koenigturbo
- Start date
if all things are equal then there are no differences. 
running a stock manifold with stock turbo, stock intercooler, stock exhaust, stock intake, stock electronics, etc will probably net you almost the exact same amount of HP that you would get running a front facing intake manifold with stock turbo, stock intercooler, stock exhaust, stock intake, stock electronics, etc.
running a stock manifold with stock turbo, stock intercooler, stock exhaust, stock intake, stock electronics, etc will probably net you almost the exact same amount of HP that you would get running a front facing intake manifold with stock turbo, stock intercooler, stock exhaust, stock intake, stock electronics, etc.
Cyrus;1850323 said:if all things are equal then there are no differences.
running a stock manifold with stock turbo, stock intercooler, stock exhaust, stock intake, stock electronics, etc will probably net you almost the exact same amount of HP that you would get running a front facing intake manifold with stock turbo, stock intercooler, stock exhaust, stock intake, stock electronics, etc.
then why do people do it just for looks? more room?
most people do a whole slew of supporting mods to go with it.
larger and more efficient intercooler and tubing, upgraded turbo, upgraded fuel system, engine management electronics, etc.
it also reroutes the post-intercooler air away from the hot side of the engine, keeping the charged air as cool as possible.
and of course, it does clean up the engine bay.
larger and more efficient intercooler and tubing, upgraded turbo, upgraded fuel system, engine management electronics, etc.
it also reroutes the post-intercooler air away from the hot side of the engine, keeping the charged air as cool as possible.
and of course, it does clean up the engine bay.
You will see a difference. Less ic piping. Less pressure drop. Also less heat from the ic piping going over turbo.
pressure drop occurs in the IC. replacing just the intake manifold wont change that. less IC piping, true. but that will only give you better throttle response, not increased horse power.
i suppose you could see a modest increase if the IAT dropped significantly due to the post-intercooler piping not being routed over the turbo.
i suppose you could see a modest increase if the IAT dropped significantly due to the post-intercooler piping not being routed over the turbo.
There is also the theory that a front facing manifold forces more air into the back cylinders than the front, due to flow characteristics, causing them to run leaner, and hotter as a result. So you have to tune for the back cylinders, and you have uneven power across the crankshaft amplifying wear. This theory makes sense, but haven't seen any fact based evidence to back up the theory.
I've never heard that before. I could see it with a manifold built by some Cletus in his shed with a MIG welder and some spare parts. But a properly built FFIM that has had flow testing done shouldn't have this problem.Dirgle;1850369 said:
-AM3
The numbers for "increased throttle response" due to shorter intake piping are a pain to work out, but it amounts to a couple of ms.
For heat entering the IC pipe... There will be some, but there are much easier ways to avoid that. Insulating wrap, for example...
Really, the point is the mods that go with it, generally a larger intercooler, hardpipes, most people will also go for a larger throttle body as well, and I've seen people also use this as an opportunity to upgrade the ignition system and go coil-over-plug. It seriously annoys me when they then post the results as an "FFIM" upgrade.
And, of course, there will always be the people who go FFIM because it looks cool.
For heat entering the IC pipe... There will be some, but there are much easier ways to avoid that. Insulating wrap, for example...
Really, the point is the mods that go with it, generally a larger intercooler, hardpipes, most people will also go for a larger throttle body as well, and I've seen people also use this as an opportunity to upgrade the ignition system and go coil-over-plug. It seriously annoys me when they then post the results as an "FFIM" upgrade.
And, of course, there will always be the people who go FFIM because it looks cool.
Only off boostDirgle;1850369 said:
Once on boost the Plenum acts as a reservoir of compressed air and as each vale opens is draws on this reserve.
IJ.;1850498 said:Only off boost
Once on boost the Plenum acts as a reservoir of compressed air and as each vale opens is draws on this reserve.
I kind of figured that would be the case. Considering how much time people actually spend off boost, I imagine it can become a significant concern. Logically it makes sense, but I haven't seen any hard info on the matter. But i'm more apt to take your word for it than JohnQ public.
Another MkIII;1850376 said:
The stock manifold on the RB26 was known to cause the #5 and #6 cylinder to run hot. Changing the manifold to a better design would solve the problem. No engineer by the name Cletus at Nissan. The Toyota manifold seems largely immune, but there was a lot of debate on supraforums many years back.
I ended up going 6x Meth nozzles due to my FFIM having crap distribution so yes off boost there will be a difference but as we're dealing with a dry intake it's not as bad as it would seem, air can turn corners fairly easily and about the only place you might notice it would be in economy but even then I doubt it.
Koenigturbo;1850324 said:
Lots of people buy things strictly because of what it looks like. It is their money. There is no gain to facing front. If you get a new plenum that is larger, or shorter routing, that is useful.
Looks and spark plug changes are so much easier! Cant tell if it's the fresh rebuild or the manifold but I seem to.have slightly quicker throttle response
About the only person that's done them back to back was Duane, and I remember him picking up quite a lot of power. There's still a lot of variables though (runner length, porting, etc)