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I didn't know where to put this, but to my knowledge most of the knowledgeable people browse here.
I had some time today so I was browsing some forums trying to get my j knowledge where it needed to be and came across an interesting set up with no real answers.
Does the j37a2/a4 heads fit onto the j30a4 block? People seem to have done the j37a1 head/j30a4 block and these two heads look identical according to a Google search.
Yeah, while scrolling through forums I saw that exact accord lol. I think he made 324whp? And the guy who owned it was like, that's my accord! Haha
Just curious because while building my j35a3 I still have time to make changes. I probably won't but I'll entertain the idea, cuz it's FUN lol. An option could be a stroked j33 with j37a2/4 head. I also learned that these engines probably work best at higher rpms because they apparently don't make power using high lift but rather longer duration (haven't seen an answer for this one either). The cam lobe on the intake on the j37a2/4 is smaller than previous generations yet it produces more power? And then the head supposedly flows better with improved tumble port design.
I think it wouldn't be a bad idea. People seem to make decent power with single port engines N/A. And 324whp with that intake? Seems to me a lot more power would open up with DTB.
I know the bore doesn't match. It's 86 vs 90. But tons of Honda people do these swaps all the time. Usually what happens is car on builds up carbon in the gap and it'll be fine. I mean, those j30 guys have done all sorts of head swaps including the j37a1 head swap. Can it last? Idk. Perhaps you could mill the head to reduce the size of combustion chamber? I think someone said max is .004
J37a2/a4 has dual vtec system. So the intake and exhaust are more aggressive compared to the previous generation.
The bore must be close to the 90mm. So you will need at minimum a j32 block (89mm bore)
Trust me you will lose power because the bore doesn't match. My Compression ratio is lower than stock since I put a J35a8 head on a j30a5 block. Perfect for boost
You could mill the heads but since it now sits lower than stock you run the risk of piston to valve if you ever decide to run larger camshaft.
Also Matt has more than just an intake. He has PCD and a Jpipe at the time of dyno. Then now has PnP runners and a cut out.
for the j37a1 head swap. Someone on V6P dyno PnP j37a1 heads with rl camshaft vs stock heads and RL camshaft and still made more power with the stock head and RL camshaft on the j30a5 block
Last edited by thisaznboi88; 04-17-2017 at 06:52 PM.
J37a2/a4 has dual vtec system. So the intake and exhaust are more aggressive compared to the previous generation.
The bore must be close to the 90mm. So you will need at minimum a j32 block (89mm bore)
Trust me you will lose power because the bore doesn't match. My Compression ratio is lower than stock since I put a J35a8 head on a j30a5 block. Perfect for boost
You could mill the heads but since it now sits lower than stock you run the risk of piston to valve if you ever decide to run larger camshaft.
Also Matt has more than just an intake. He has PCD and a Jpipe at the time of dyno. Then now has PnP runners and a cut out.
for the j37a1 head swap. Someone on V6P dyno PnP j37a1 heads with rl camshaft vs stock heads and RL camshaft and still made more power with the stock head and RL camshaft on the j30a5 block
That last part is a bit confusing. Maybe I'm not reading it right? But the vtec on both sides is pretty intriguing.
You put a j35a8 head on a j30? That's 89 on top of 86. It's close to the 90 lol. It probably makes a difference but I don't think this head fits on the j32a2 or any 1st gen 32 or 35. Feel free to correct me.
And I won't run into the problem with the cam. If this head was to fit, I'd just leave it. Not look for a dyno monster but building an engine that makes the most whp using oem parts. If anything id swap pistons to raise compression.
That 324whp was the most ive seen with a legit dyno. And when I was referring to his mods, I knew he had to have full exhaust mods but the intake side. If the exhaust side is better already better than any other j engine because of the vtec, doesn't that suggest that you could get even MORE air through the intake side and thus make more power? Everyone says starves for air. I think he can make more power if he had a way to get more air into there.
if you are using a first generation motor then it will not work for you. If you have a first Gen J motor. You posted in the 3rd gen TL section so naturally I thought you had a J30a4/5. If that is the case it will fit. But you are better off swapping in a larger displacement motor to make the best of it.
Here a picture of the dual vtec (intake and exhaust, There are 6 lobes on the camshaft vs 5 on the regular J intake only vtec)
if you are using a first generation motor then it will not work for you. If you have a first Gen J motor. You posted in the 3rd gen TL section so naturally I thought you had a J30a4/5. If that is the case it will fit. But you are better off swapping in a larger displacement motor to make the best of it.
Here a picture of the dual vtec (intake and exhaust, There are 6 lobes on the camshaft vs 5 on the regular J intake only vtec)
Shit lol. Here I was thinking that the j30a4 was 1st gen but it's right where they made the change from dbc to dbw. Damn.
But just to confirm. The j37a2/4 head fit the j30a4/5? Yes correct? But you will have overhang and will have to use the j30 gasket?
But I posted here because this particular forum gets a lot of traffic and I know there are a ton of knowledge guys who come here.
But looks like this swap got more complicated than I wanted. My biggest problem is that I love my ek chassis too much and don't want to switch to something that's heavy lol. This is limiting my options pretty good.
Looks like to complete a swap line this I'd need to buy a crashed accord and swa0 everything over and even then so, not a lot of info online for that particular swap.
Do you know if the j30a4/5 use that "bus can" system or what not the TLs use? That was a huge limiting factor for us civic people so far I guess. People have done it but the harness is probably special. I've seen yungone has a j35a8 civic but he did his own harness and he commented that the harness offered by RPM systems.
J30a5 ecu doesn't use canbus it uses k line. Need to swap ecu to the 07-08 tl and require stuff
That's Good to hear. That means you can run this with Hondas. Perhaps a future swap when those parts become a little cheaper lol. Got to build this other guy first.
You think maybe Honda decided to give the j37a2/4 heads smaller lift on intake side and more on exhaust side because they realized that they were limited by cam size regardless and could make more power by just opening the exhaust side more? Like bigger intake lobe nets less gains than bigger exhaust lobe?
This kinda makes a lot of sense. I mean, from what I've seen, that was probably the right thing to do because I'm pretty sure most people make the gains off of header/exhaust vs cam/intake. Hell, the first mod most people suggest for j32a2 is long tube headers. For j35a8 it's prefer deletes and aftermarket j pipe.
Too bad we don't have these flow tested lol as I would personally love to see how much difference there is intake vs intake and exhaust vs exhaust of the j32a2/j35a3 head and j37a2/4.
With a better exhaust removing system that j36 accord easily hit 324whp with dyno graph. I wonder what kind of intake mods other than DTB would help get more air into the engine as getting out really isn't the problem? I'm not an engineer yet, but just looking at the intake other than space limitation, I don't get why they designed it the way the did. On every single other v engine the plenum sits in the middle and the air gets split accordingly. On on j3x engines, the air has to split two directions before getting to the runners? Why?
I've been looking at pics between 60 and 90 degree v6s and I honestly think that it's a space thing and there is no real benefit between either.
For instance, 60 degree v6s are taller therefore cannot have a huge plenum in the middle because the hood wouldn't close in a car. So to combat this issue they split the plenum in two. For a 90 degree v6, this doesn't seem to be the problem as the engine.
Haha, maybe that's how it goes. All I know is that I'm already gonna have problems closing the hood to my car.
04-17-2017, 04:50 PM
