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Discussion Starter · #1 ·
Hey Gary on your new setup is the compression the same(11:5:1)????? If not what CR is it now with your new setup??? If it's stock do you think you would see a big difference say if you put in 12:5:1 CR vs. stock?????
 

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I'm going to have the new set-up on the dyno hopefully in mid april.. It will be 12.5:1
I am replacing my rods with Crower rods, not sure on the Billets or Maxi-lites yet..
I am also going to be running the CP-Pistons 12.5:1 piston.
The man reasoning I guess is if I get bored with drag racing I will be able to sell my cars shell and keep the motor for a semi-daily driver...

As for the difference I think is in it. Well I think there might be 20whp maybe more. the biggest benefit for me is changing fuels. I will possibly see another 10whp just in the fuel I run.
Also with the higher compression you could port the motor a little bit more and see some more gains there aswell..
 

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Discussion Starter · #3 ·
cool. Also is there any BIG difference in porting the K20A head since it flows pretty good from stock. Reason being if you only get 5whp from porting the head, that's not really enough to justify the money spent on it.

What's a good shop to do so??? Portflow???
 

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What Gary is saying is that you are not going to see big gains from serious portwork if you stay with the stock compression (11.5 on a K20a) since the stock ports are pretty good already. Now when you up the compression to 12.5 you will be moving more air and thus be able to maintain velocity in a larger port...
 

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On the 11.5:1 set-up you will see some gains.. BUT not from porting the intake side of the head. honestly it already flows alot, you might find getting the exhaust side done makes the biggest gains, since thats where the restriction is..

I can't make any claims on the power the porting alone would make since I decided to sell my ITR cams instead of running them and back to back dynoing the port job.
But personally I think I will see 50+whp from the porting and the stage 2 3/4 crower cams.
Deep down I hope to break well pas 300whp with the motor running 12.5:1 but we will all have to wait and see about that..

AS for who I would recommend.. well not being in the states its hard to say. I'd talk to K20Ahondas about who he uses I think its R&D (does that sound right) I beleive they have a head exchange system going now. you send your head and get one a day or so later back. and its a resonable price. BUT it is done on a CNC machine, so you may find with a bit more time and the right tools you can clean the porting up even better..
 

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Discussion Starter · #6 ·
Thanx, Gary are you going to sleeve the block as well???(sorry for so many questions)
 

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i sent mine to port flow and they did an great job. although i haven't run it yet the work man ship is second to none. i'll have to get some pictures up for you guys.
 

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Discussion Starter · #9 ·
evilxkid said:
i sent mine to port flow and they did an great job. although i haven't run it yet the work man ship is second to none. i'll have to get some pictures up for you guys.
Pics would be great!! How much was it total for porting the head shipping etc, Also could you list what EXACTLY they did??????

Gry, thanx
 

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hey non-vtec, congrats on the huge numbers. do you think you could release more hp by matching the itbs to the head with some porting?? when you go for new pistons, are you going to stay at 86mm bore???
 

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the only porting on the intake side was to Match the HEAD to the ITB's since the runners were bigger than the ports. yes there will have been gains from doing that alone..
I plan to stay with the 86mm bore at this stage. I don't mind being one of the 1st people to try and get 300+whp out of a K20A, but I don't really have the budget build motors that either don't work or don't last. so I'd rather see some of these hybrid's, bored out cammed etc motors get a few more k's on them first.
 

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well best of luck to you! i tend to agree with you about the early bird and late mouse etc...
Did you stick with the stock size valves for clearance reasons or do you feel theres not much to be gained +1mm oversize?
 

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I stuck with them for both reasons really. You can read 100 things about building motors and the parts people sell but until you instal them yourself and cherck them all you never can be sure. Plus everything on the market is for a K20A2 not the JDM K20A, we didn't know if there would be any issues so we decided to play it safe on the clearance..

You might also find that on a K20 that oversized valves along with bigger ports will actually hurt the perfromance, due to there being to much air-fuel in the chambers. The exhaust would probably benefit the most from the valves being 1mm bigger, but I doubt the inlet would make alot of difference.
But once again, you really need to check the clearances of the stock parts before you go bigger, just to be on the safe side.. I know with B-series Valves you cant mill the heads with alot of oversized valves etc..
 

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well in dreamland (where money si no object) id love to see if an 89mm bore would work. +1mm oversize valves would give the same velocities as stock. with increased capacity the head gasket could be thicker and still give a high CR. Only thing is to figure out valve to valve clearance (and id like to run iVTEC). Dont know if its possible, no way id spend money to find out!!
 

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checking the iVtec is easy, if you dont have V-P clearance then get the toda killer gears, if you do have V-P clearance then you can run the iVTEC.
I have thought about doing a big build aswell but at this stage I would rather make power in steps and get the power I have to the track first. then set up in power slowly. plus I also need my motor to last at least one season, maybe with a new set of rings and bearings to run a 2nd season.. Since I don't have a full on budget to race with yet. Although over here the scene is going pretty fast and sponsors are starting to come along abit more..
 

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i was reading about the ips K2 cams, the V-V clearance at 50 deg VTC is less than 2mm. So for crower stage 2 3/4 it would be interesting to know the V-V clearance at full VTC.
 

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Discussion Starter · #17 ·
Gary what size exhuast are you running????? With the N/A build we've been discussing, do you think the dtr-fab 4-1 headers would be better than the 4-2-1's?????? What configuration headers do you use????
 

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I got a set of DTR 4-2-1 header for an EK off a mate in aussie. I just cut and bent them to suit.. As for the exhaust I run a 2 5/8 to 3 1/2" megaphone thats about 400mm long on the end of my header and thats about it..

I plan on going to a 4-1 with the megaphone, but I might go to a 3" exit from the header though, I will test it first though like I did with the DTR-FAB header..

I tried a few exhaust set-ups with my header, I can recomend a 3" system with one resonator and one muffler if you can get away with the noise.. We dont have to run Cat's here either so that saves alot of hassle..
 

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Discussion Starter · #19 ·
Damn Cats :mad: A 3" sounds about right, even from the header. Is there a particullar reason you're switching to 4-1????
 

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Noob question here. Gary, you mentioned your clearances were pretty tight with the new cams, so wouldn't higher CR pistons cause even more problems, or do the pistons have valve reliefs in them or something? I've only ever seen pent-roof B-series pistons, are they similar?

My biggest worry with modding a JDM K20 is the V-P clearance when using bigger cams.
 
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