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For starters, getting a top of the line 4-2-1 header will get you the most usable TQ for pulling out of the corners. I would suggest ASP or Hytech. A 2.75"-3.0" exhaust.

Which factory airbox is the best? The DC5 Type R or The Civic Type R FD2..?
 

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2002 DC5 Type S
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On the Type R (DC5) air intake box, one can save money and just buy the 05-06 Type S. The airbox feed is Tube A, Air In pn# 17251-PRC-010 @ $18.98. They are the same parts. The feed tube scoop is the same as the PRC Type R.

I am wondering about the FD2 Civic Type R intake air box and it's changes over the DC5R assembly
 

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2002 DC5 Type S
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** ANY STEEL OR STAINLESS STEEL RETAINER/KEEPER/ SHIMS ALLOWED. ANY TYPE OF VALVE JOB ALLOWED. VALVE JOB ANGLES OPTIONAL.**
-- 3 angle valve job

** ANY VALVE SPRING COMBINATION OR DESIGN **
-- Supertech Beehive Valve Spring. These provide weight savings in the valvetrain department
 

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@Them Witches I have a narrow build window and knew it would be best to ask all of you what would be best. I wanted to keep the bottom end stock if possible. As far as the head I was thinking a 5 degree valve job to help with corner exit. Lightweight springs and retainers. Stage 2 cams.(Deciding on the right cam is what started all this).s see one type of header. Kpro and a good tune. That’s basically all I had in mind when starting this. I wasn’t sure what brands. Honestly the more I researched the more confused I would get. One thread would say a certain cam is the best. The next thread it would be garbage. Just so much out there. I hope to start a thread and get direct info for my build. So far the feedback has been great! Thank you all
For starters what chassis are you using?

One of the most popular stage 2 cam I have seen giving good results and seems to always get consistent good reviews is Drag Cartel's 2.2. Supertech Beehive Valve Spring seems to be the lightest and very popular choice too. The beehive takes less material to make vs. standard circles that is why it weights less. The 5 degree valve is said to provide close to 50% of the cfm gains relating to headwork, and is a great choice.

In motorsport racing, the header can be the factor that gives you ability to win sprints after the exiting turns. One made for your build specs can have higher turn around times, so if you go that route which I would, jump on that. For Hytech headers you have to contact John via inlinefour.com. To my knowledge, ASP is not making headers at the moment due to supply costs relating to covid. There are dealers that have ASP headers in stock depending on your chassis, they are $1500. That is what a top level header goes for and in comparison to the $800 header I just bought. ASP & Hytech are worth their weight in gold relating to motorsport racing. If you can gain 8-14whp over a standard mass produced header that would be worth it, the fact you are having a 5 angle valve job in the exhaust you will most likely see the whole 14whp gain over other headers. Plus the TQ gains would be seen throughout and down in the 3500rpm range and up.
 

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2002 DC5 Type S
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ASP Header in stock $1350 and up:

Wood Tool Automotive exhaust Muffler Auto part



 

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That chassis looks rigid. So your car is going to look like a low rider stock car? Interesting stuff. Is this going on a circle dirt track or a road course type track?
 

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This is an Integra that Someone else built View attachment 105574
This is the type of track we run on. This track is 4/10 of a mile with 17 degrees of banking in the turns and 7 degrees on the straights View attachment 105575
That track looks like 16-17 sec lap times for stock cars with V8's. Always turn 4 is the "walking" turn that is hardest on the suspension. I used to drive my old Honda on a track like that for fun.
 

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Yeah if you are not going to tear that engine all apart to gain extra power here and there - get a top of the line header and exhaust. It will make or break the difference in being competitive, I am willing to bet others will be running top of the line headers. A good header provides quality "transient response" - the ability to get from the lowest rpm to the highest rpm the fastest making usable power the whole way.
 

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17.702 took the pole here last race in the class I’m running. The late model stocks(V8) Josh Berry who drives for Dale Jr was on the pole with a 16.067
I was spot on with those lap times. Langley Speedway is close to me.. Buddy of mine ran a 18.2 lap in 2001 Integra Type R with a SC K20, we has been racing for over 30 years though.. he actually had someone in his way so he would have hit 17's

V8 stock cars run that same time at Langley, so the tracks must be identical
 

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That's a fair and a no-high-price competition basis (y). So the playground are: pistons, intake, header, exhaust, some areas of the head, intake manifold choice, camshafts, tuning. I am convinced this is at least enough to reach 280 hp/180 ftlb's at flywheel, so far I understand the rules.
200ft-flbs at the flywheel good lord that is awesome. I need to have you design me an engine. Like I could afford it hahaha
 

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@Them Witches thanks for all your help. I feel confident I can make the car turn and get the gearing right. I have never built a Honda engine and wanted to make sure I got the most potential out of the engine. Your advice has been priceless.
you are welcome brother. I am here to help, KBuilt is another good one to talk with too.
 

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The rules are saying you have to have a factory air box for the intake or can style. You should call the tech guy and get a image of the can style image they refer to. The air boxes can be modified internally by removing the ribs inside that disrupt flow around the filter. I will link the information to this thread.

I did not see anything about the filter having to be the exact oem filter. Mugen and Spoon sell filters that are times over the OEM filter.

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SPOON SPORTS AIR CLEANER INTAKE FILTER - DC5 EP3
SPOON SPORTS SKU: 103876 PN: 17220-DC5-010

Tire Wheel Automotive tire Synthetic rubber Tread



2002 Honda Integra Type R (Acura RSX Type S) factory air box modification

Motor vehicle Automotive tire Automotive design Hood Automotive exterior


Motor vehicle Automotive design Hood Automotive exterior Automotive tire




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In in this image you can see how the airbox was design from the factory. The lower hose is the air supply tube. This tube can be removed and a round 3"-4" supply duct can be installed to the front bumper or other type of air scoop. This will basically provide you a solid ram air set up that should be within the rules b/c you are using the air box to contain a filter like OEM.
Automotive lighting Automotive tire Auto part Bumper Asphalt


The air supply tube PN# (17228-PRB-A01) is the piece that connects to the throttle body is the same as the Honda Integra Type R (K20a) & Acura RSX Type S (K20a2). Again if rules allow the airbox, they may allow this silicone air supply tube is a better option because it is smooth on the inside unlike the OEM piece that has multiple ribs & lips that hurt air flow. The OEM piece is made like that to allow for engine movement and vibration b/c stock engine mounts allow the engine to move too much. There are extra HP to be gained using the smoother internal supply tube.

TEGIWA SILICONE INTAKE PIPE HONDA CIVIC EP3 INTEGRA DC5
SKU: K-INTAKE-PIPE
Manufacturer: Tegiwa

Font Auto part Plastic Electric blue Magenta


If you cannot make these simple altercations to the airbox, I would still want this because the factory air box has supply duct that at least routes air into the airbox that you can make a ram air duct or scoop to feed the airbox. The can can only be 8" long. The airbox will give you move TQ for pulling out of the turns down low to mid range. The airbox will also store a higher volume of air around the filter that will pressurize due to it's design. the better you can supply the air the better it works. As I was saying about the (PRC = Type R spec) and the (PRB = Type S spec) supply duct, there is a difference in the (PRC) it is larger, if the tech says this part has to be OEM as well.
17251-PRC-000
Add inquiry
TUBE A, AIR INTAKE1JPY 1,846USD 17.58
 

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Super Moderator
2002 DC5 Type S
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I think the modifying the inside of the airbox is legal because you are not opening or changing the actual shape of the airbox. this mod is worth 2-5HP b/c you are allowing the air to swirl around the filter better without the ribs disrupting the action.

The airbox can be insulated on the outside to keep heat soak down. A thin SS plate could be attached to the left side and back side to reflect heat from the header.
 

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2002 DC5 Type S
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Since you are having the 5 angle valve job done the head will be off. Have the head milled to increase compression that way you can run a OEM head gasket for the best sealing. Since the head is off, cleaning it is huge. the exhaust ports right after the valves will have exhaust smut build up. A simple pick and light sanding can be done there to pick up more horsepower. you do not have to sand the exhaust port near the exit, the sanding near the valve will not be seen b/c of the ports shape even with a light. You will also gain better volumetric efficiency cleaning the exhaust port there. they will not see it.
 

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2002 DC5 Type S
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If one can place it in a naturally feed cold air place beside the radiator, what a great option.
Yep right to a 3.5" velocity stack filter combo. Rules did not say anything about velocity stacks.

Wonder if her could get away with this $560 intake set up with a high flow ITG spun filter:

Tire Automotive tire Rectangle Rim Cylinder


JC60C (Large Cone) Size Options
Part No.A (ID) / B (OD)CDEFGBHP
JC60/80C80 / 8318055163218149450
JC60/86C86 / 8918053163216149480
JC60/93C93 / 9618050163213149500
JC60/99C99 /10218050163213149520
JC60/114C114 / 11718045163208149530
JC60/124C124 / 12718040163203149540

Rectangle Font Symmetry Diagram Parallel
 

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2002 DC5 Type S
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This filters should be used with care and consideration. In dusty tracks or environments I wouldn't use it as the filter efficiency for real dust particles. Test dust norms like the Arizona dust ARIZ-TD (ISO 12103-1) in A2 size will make this type of filter really looking bad. It can separate leaves and flies from air but not efficient enough in the area of around 100 µm and smaller. Using such a filter need a higher oil filter and oil change interval frequency to reduce the effect of wear, but it doesn't stop the wear like a Paper Filter does it.

Next point the filter area is pretty low, there is no area increase technology used like folding of filter material. This is only possible by the fact of it's low filter efficiency. For me those filters types are for applications having maintenance intervals of 50 h and less.
indeed. I concur.

I want one for my little sreet demon
 

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2002 DC5 Type S
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🤔...really?

Something adding to the OP's question, which may interesting too about the capability of the K-series.

View attachment 105797

These curves are from a 1D simulation of different 2000 ccm engine setup's for different applications I've done. Y-axis scale refers to flywheel. The blue-green-engine, called DAMPFHAMMER, was already on the dyno and made 206 ftlb'[email protected] rpm before the gearbox needle bearing cages melted because of lost gearbox oil. The red-black-engine is my actual development, called DAMPFHAMMER HD. Anyway, there is a potential for around 200 ftlb's at flywheel, not only for peak torque.

If you want to follow what's coming next you can follow my built thread: You want to win up to $50? The 86.5x86 rebuild question! | Honda / Acura K20a K24a Engine Forum
Markus I want to follow the progress of both engines.

i want one for my street demon
 

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2002 DC5 Type S
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This filters should be used with care and consideration. In dusty tracks or environments I wouldn't use it as the filter efficiency for real dust particles. Test dust norms like the Arizona dust ARIZ-TD (ISO 12103-1) in A2 size will make this type of filter really looking bad. It can separate leaves and flies from air but not efficient enough in the area of around 100 µm and smaller. Using such a filter need a higher oil filter and oil change interval frequency to reduce the effect of wear, but it doesn't stop the wear like a Paper Filter does it.

Next point the filter area is pretty low, there is no area increase technology used like folding of filter material. This is only possible by the fact of it's low filter efficiency. For me those filters types are for applications having maintenance intervals of 50 h and less.
that makes sense the filters to not last more than 50h or so. it would be nice to see back to back dyno's of a standard fold type vs. these ITG "race" filters
 
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