Many Honda and Acura V6 owners look to the grand-daddy of all J-series engine, the J37A4, for OEM upgrade mods. The primary item of focus is the large, Magnesium manifold topping that engine. However, there is some debate as to what the best course for intake manifold and throttle body use is ideal on a J-series engine. It’s well known that earlier J-series had removable plenums and internal trumpets that worked great and could more readily be ported out.
Heeltoe went out and got some information to help clarify things!
We’ll be updating this article as we learn more about the J37 intake manifolds and their applications.
Updated Dec 2, 2016:
This article was originally written to comment on the performance differences between a J37 Magnesium intake manifold versus porting out a factory J-Series manifold. Our expert adviser suggested that modifying the stock manifold was a more worthwhile effort when the cost is weighed out. But the market has decidedly chosen that modifying the stock manifold is too inconvenient when compared to simply buying a new part which works the same or better. Why?
Firstly, the stock manifold is not easily modified. Older J-series engines had removable plenums which allow them to be opened and ported with plenty of access. Anything 2004 and newer, though, is all one piece and is not really able to be opened up.
Secondly, who does the work if you want to send it out? Efforts in getting people to actually DO the work after they smugly comment “bah just get it ported” all seem to disappear when you ask for a reference or contact. Even people who say that “can” do it aren’t readily able to.
Thirdly, there is downtime to consider. If the customer doesn’t want downtime, they need to source a replacement manifold and the “it’s cheaper to port” argument gets thinner right off the bat.
Lastly, nothing in the parts world ever remains static.Â We’ve just recently revised and redone our manifold packages with new, lower-cost options for many J-series owners. Check out that listing here:Â HTSpec J37 Magnesium Intake Manifold & Throttle Body Kit, Honda J-Series V6 (ALL Single-Port Exhaust Engines)
It is fairly commonly known that by upgrading the intake manifold on an engine, either by increasing volume or reducing restriction, more power can be produced within the engine. This is because air is more efficiently delivered.
As Honda engines have grown in size and power requirements, so have intake manifold volumes. As of this writing, the J37 intake manifold is an increasingly effective upgrade to do on mild and serious engine builds. But, are there real benefits over stock manifolds, or ported and polished ones?
We consulted Andy Gerzina, noted J-series engine guru, for his input. His statements to us, and we paraphrase, were:
Does the J37 manifold produce more power over stock intake manifolds which have been ported and polished?
- Yes, to the tune of 2-3 HP over the rev range.
Do you generally recommend a J37 intake manifold to people building engines?
- Since the cost of the manifold is over port work is relatively high (even more after considering a throttle body is added), and the gains are minimal, I find it more economical to upgrade the stock components.
It seems that if someone was starting from scratch and wanted maximum power a J37 package may be feasible.
- It would depend on the person’s situation. On one hand, money would be saved obtaining used stock parts and modifying them, but it is also more time consuming and demanding of resources other than money. Simply ordering a J37 package may be easier for most users.
Are there any drawbacks to either porting or upgrading to the J37 intake manifold?
- On Automatic transmission cars, no issues have been recorded or found to be troublesome with J37 manifold and/or J37 throttle bodies. On modern drive-by-wire j-series vehicles equipped with manual transmissions, there are well-documented rev-hang issues with the J37 throttle body, regardless of which manifold it is used in conjunction with. This change in drivability isn’t something one could not live with, but it may be favorable to port/polish the stock manifolds internals if you have a 6MT for seamless operation on the street. Currently, there is no consumer purchasable available adapter to convert a J32 or J35 drive-by-wire throttle body to a J37 manifold to solve this issue. With such an adapter in conjunction with a J37 manifold, performance gains are equivalent to porting a stock 2004-2008 TL/TL-S manifold.
Thanks, Andy, for the clarification!