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J32A3 Stroked and Bored to 3.7 Liter Project

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25K views 55 replies 13 participants last post by  sasa  
#1 ·
So currently I am the owner of a beautiful 2004 Accord V6 6 Speed Coupe :)
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I've had it for about 6 months and love it! Well long story short I was being a dumbass one day and misshifted into second from some hard driving and from there basically new it was time for a new motor. I kept driving the accord even though it was giving me the misfire codes from all cylinders as well as the random misfire code. I could hear a tick from my top end too but never got around to looking further into it as much as I wanted to cause I just didn't have time at the time. I had finally found an unmolested J32A3 that I purchased and continued my research. As I kept driving the accord it finally came to the point where the engine started knocking from the bottom end and at the point it was time for me to stop driving it and start working on this project. So the following is what I plan on doing with the J32A3 motor before I swap it in.

Cleaned & Sleeved J32A3 Block Bored by 1mm(90mm total) W/ Piston oil Squirters
J37 OEM Crankshaft(from 07-09 MDX)
J37 OEM Bearings
J37 Rods(looking at Pauter)
J37 90mm Wiseco 11:1 CR Pistons
MLS 90mm Head Gasket
ARP Head Studs
J37A4 PnP Heads with full Supertech Valvetrain
J37A4 PnP IM, Runners & TB
Gates Racing Timing Belt & Water Pump Kit
Unorthodox Underdrive Pulley W/ Gates Belt

So basically my total displacement will be 3.7 Liters tuned with a TL-S MT ECU connected to FlashPro. Once the motor is finished I will be running it all motor for a while up until next fall where I plan on giving it some boost. I will also be running my stock tranny for now but in the works of purchasing a 6mt W/ LSD & Axles from a 06 TL with low miles. As I am still collecting parts I still do have questions that are unanswered and will appreciate all the help I can get.

Are the J37A4 Heads with the Dual VTEC directly bolted on with the J32A3 Bottom End?
With the J37A4 Heads & IM, Runners, TB will any extra wiring need to be done or will my J30A4 Harness work just fine with the J32A3 Bottom End and J37A4 Top End?
Is the 07 Tl-S MT ECU directly plug and play with the Hondata Harness?
Is there anything else that I am missing for the build that I might need?
Any Suggestions?
 
#11 ·
I haven't done it yet but I have pictures from someone elses build that did. I'll upload them here once I find them.

If boost is in your future at all why go for 11:1 instead of something around 9:1.the J is not timing friendly in the first place and you will be artificially limiting your power potential by using that high of cr. Also, you didn't list cams, or I missed them. What is the rationale for that high of a cr if you are running stock cams?
I will be running e85 all the time and plan on using the same cams that come with the j37A4
Build looks good, minus the J37a4 heads. They simply won't work. Keep us in tune with progress.
Could you please tell me why they won't work?
 
#4 ·
If boost is in your future at all why go for 11:1 instead of something around 9:1.the J is not timing friendly in the first place and you will be artificially limiting your power potential by using that high of cr. Also, you didn't list cams, or I missed them. What is the rationale for that high of a cr if you are running stock cams?
 
#7 ·
Because it's SOOO easy to do right? Tony_the_tiger made 700+ on 12.5:1 - does that make it the best scenario, or ideal? Also, his 94oct. numbers were with meth and it only made 650. It took 114 octane to make 750. So, over 100 HP was left on the table by running that high of a CR.

Why put the motor at a disadvantage from the getgo if it is being designed with boost in mind? Sure, newer OEM motors may have 11:1 or even higher on a turbo, but they are typically direct injected, which changes the game. For a port injected engine that will see boost, I wouldn't go above 9.5:1. I've seen some B series run 10:1, but they have to run reduced timing, making the motor lazy.

For the J engine, I wouldn't want to run more than 9:1 knowing how bad these motors knock in stock form. Now, if you want to run E85 all the time, you might even surpass MBT at 11:1, but not everyone has access to it, and fueling requirements increase greatly.
 
#14 ·
^That's essentially the same setup I have going right now although I went with a Stealth 340 pump over the walbro and I'm running 725cc injectors from Injector Dynamics. Just make sure you verify the injectors aren't too tall. I was forced to go with ID because the ones the shop wanted to use wouldn't clear the intake manifold and they were the only ones they could find that were short enough.
 
#15 ·
if your doing e85 you need at least 1000cc mininium especially for 600-700whp power level
 
#16 ·
Good luck with the build. Not sure if the Dual VTEC heads will work, but I don't see why they wouldn't according to Azine. My heads are still for sale at a reduced price if the J37a4s don't work.
 
#21 ·
CAM LOBE HEIGHT MEASUREMENT CHART for J37A4
INTAKE EXHAUST
PRI 34 299 mm (1 3504 in) 36 734 mm (1 4462 in)
SEC 35 932 mm (1 4146 in) 37 370 mm (1 4713 m)

doesnt seem that great. for the same price i rather get billet cams. killer vtak style
 
#24 ·
2012 MDX 34.299 + 35.932 intake and 36.760 exhaust 4 lobe
07 MDX 35.112 + 36.394 intake and 36.389 exhaust 5 lobe
07 RL same as 07 mdx
04-08 Tl 3.3 35.041/35.284 + 36.445 intake and 36.326 exhaust 5 lobe
05 av6 35.041/35.284 + 36.445 intake and 36.326 exhaust
 
#26 ·
E requires 30% more fuel. With a walbro 255 and 440cc injectors at almost 500hp i still have more fuel capability. I did the math and a 750cc will work at 700-750. If 1000cc make you feel more confortable the price is the same i think, but under boost tunning may be challenging.

E is becoming very hard to find in the Northwest so make sure you research availability in your area.
 
#30 ·
No crazy math wizardry on it from me. Just from experience and what i have today. Currently I am at 82% +/- duty cycle with my setup and have been looking into running a flex fuel setup due to availability of E85 (which is really E60 mostly). Based off what i have now vs. desired 700hp knowing E requires 30% more fuel consumption i arrived at 750cc required. If you use online calculators with my current setup it will say i can achieve a max of 350whp at 90% duty. I have far surpased that.

Worst case you can always tap in a 7th injector if you run out of fuel.

Hope someone schools me on this so i can change my thought process and start looking for 1000cc injectors :).
 
#31 ·
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Trust me when I say that j37a4 heads are compatible with the j32a3 as well as the j35a8. The only other "issue" I've encountered so far when doing this swap is ensuring that the oil pump is capable of putting out at least 70 psi above 3000 rpms when running these heads. As they do require a much greater amount of oil to activate the rocker locks due to the added quantity of parts involved. I'm sure some of you know that stock Honda oil pumps can be shimmed on the pressure relief valves to modify the pressure at which they begin to bypass oil which means that simply modding your stock oil pump should suffice in supplying adequate amounts of oil during VTEC engagement. Other than that, I've found no other issues or reason for concern.

Aside from this, OP, I'm in total agreement with the compression ratio dispute. If this were a NA build I'd say go for it but when you raise the compression of a boosted engine, you do effectively lower the max amount of boost it can take by increasing its effective compression ratio (ECR) which is basically a formula that factors boost and compression to determine a safe area for an engine in keeping it out of detonation. I'm aware of the few people that say that keeping the compression high means nothing as long as your tune is spot on...and technically they are correct to an extent. However, the fact still remains that when you add compression (which is basically kept for low end response on a boosted engine), you bring the detonation point MUCH closer and the only way to offset this is by running higher octane which can get very expensive in time.
 
#34 ·
Robert...

how much for what is pictured?

Do your work on Hondata installation?

:up:
This setup isn't for sale but the j37a4 heads alone (even used) are pretty damn expensive. I've sold a few sets already including the complete single head I had and I don't keep them for very long when I do get them. The pictured engine is my personal engine that's about to be installed in my AV6 that's running boost and methanol injection and FlashPro tuned on the stock j35a8 ECM.

As for your Hondata question, it was a bit vague but I'll answer it to the best of my ability. Assuming you mean the harness conversion that must be done (since this is mainly an Accord oriented forum) when using the j35a8 ECM on the j30...I can do them but they a pretty labor intensive and because I'm busy up at the shop almost year round, its difficult for me to perform such a service for anyone here. I'm an automotive electrical technician (12 years now in the electrical aspect of cars) and because I do so many repairs that involve fixing or cleaning up someone else's shoddy electrical work, I've became OCD with my electrical work. LMAO...

That being said, its tough for me to find the time for harness conversions. I definitely don't mind helping anyone in need of assistance, diagrams, connector views, pin outs, general technical help or even text/email communication to help with any technical issues or questions. The honda j-series has become my passion and always find time to help those out in need. ;)

Oh Wow so we would have Vtec on the intake & exhaust side...hondata dyno tuned numbers would be ravaging.
Yes, dual VTEC. The sound is much more "throatier" when the big lobes hit and I foresee some very exciting gains and tuning advantages coming from this if and when j-series enthusiasts pick up on the j37a4 & j37a2 heads.

No dyno tuning has been done yet as I do all my tuning on the street. I'm not one for max power as much as I am for streetability and reliability. Most tuners on the dyno, to my knowledge, tune to the edge of knock by taking a boosted engine to detonation and then pulling back a few degrees. Most will call this a "conservative tune" but to me that's not ideal to a person who's looking to daily drive their car and get the most they can out of their motor while having a little fun at the same time.
 
#36 ·
The guys are right on compression. My shop always says lower compression and add boost. Same power, but you get the safety aspect of avoiding detonation. They have explained it a few times to me, but it goes over my head. Basically they use a safe compression zone piston and then during tuning add advancement. Once you stop producing around 1% power per degree they back it off 2 degrees, which in theory will reduce your chamber pressure by half. Now techs you will probably be able to explain that much better then me.

I am looking into the same stuff for my next step and I am going to stay at low compression and throw boost at it.
 
#37 ·
You don't always have to go low compression with boost, though. Look at the K20...it makes tons of power on 11:1 compression. TUNING IS EVERYTHING.