DIY. Install For Skunk2 Intake Manifold – GSR Head
Skunk2/GSR Intake Manifold Install for GSR Head In this article i will cover the installation process of a Skunk2 GSR intake manifold (I/M) for the P72 B18C GSR head. This applies to both the JDM & US types of the P72 head. Upgrading to a Skunk2 manifold will unleash potential top-end power by removing the use of the dual-butterfly secondaries system found on all JDM & US P72 B18C ‘snail shell type’ intake manifolds ,by converting the internal flow to that of a single butterfly Type-R I/M system. Of course , there are other ways of enhancing the internal flow of gasses within your existing P72 I/M , but i think the Skunk2 I/M is one of the best alternatives and will definitely give you a big bang-for-your-buck DIY modification. Not only does the Skunk2 manifold free up top-end breathing, but it’s a bolt-on power increase of about 7-8 HP!
Below is the installation procedures.
For a neat looking intake manifold setup, when it comes to the throttle cable & bracket, you will need the following parts:
- Integra-R throttle cable bracket / Honda part # 16411-P73-000
- Integra-R throttle cable / Honda part # 17910-ST7-R01
- Throttle body pulley from a non-GSR throttle body
- A GS-R intake manifold gasket (if you’re careful you can reuse the old one)
- A GS-R throttle body gasket (if you’re careful you can reuse the old one here as well)
TOOLS YOU WILL NEED
- 12mm & 10mm socket (short + deep), rachet, and extension(s)
- 12mm & 10mm open/closed end (box) spanners
- Torque wrench
- Phillips head screw driver
- Small or tiny flat head jewellers screwdriver for injector clip removal
- Long bent-tip needle nose clamp pliers (for hose clamps)
- Plenty of rags for any spills
- Small hands !
PROCEDURE OF INSTALLATION .
1, Raise the front end of your car up and place it on jack stands
2. Disconnect the battery cables for safety purposes
3. Drain all of the coolant into a container and cover it over, so dirt will not fall in (if you plan on reusing it) and so that your pets will not drink from it!MAKE SURE NO PETS ARE AROUND!!!
If dogs or cats drink any coolant they have a good chance of DYING from it, if not stopped in time –THIS IS NOT A JOKE! It is NOT a good thing. Coolant crystallizes in animals kidneys and will give them a slow painful death.
4. Loosen your fuel cap to relieve gas pressure from the vehicles fuel tank
5. Disconnect all vacuum & radiator hoses and lines from the intake manifold using the long needle nose pliers
6. Disconnect sensor plugs and injector plugs using your tiny flat head screwdriver, etc., from the intake manifold and throttle body
7. Take the 12mm socket & ratchet to loosen up the fuel filter pressure-release bolt, some fuel is going to leak out, so have your rags ready
8. Using your 10mm socket, remove the plastic black wire harness cover from the fuel rail
9. Remove the vacuum hoses from the fuel pressure regulator
10. Again, using your 10mm socket, carefully remove the nuts that hold down the intake manifold, CAREFUL! those small 10mm screws can easily be dropped and will get lost behind the engine – I just hate it when this happens!
11. Carefully manipulate the fuel rail off. The injectors will most likely come off along with the fuel rail. Try to take care not to damage the rubber o-rings on the injectors. Also, try to not lose the round black grommets that hold the injectors in place
12. Sit the fuel rail with the injectors still in place, somewhere out of your way, even though the rail is still attached to the hose of the fuel filter. Just get it out of the way, near the battery somewhere, you don’t need to fully remove it.
[ Support Bracket Removal ]
13. If your standard OEM P72 intake manifold hasn’t been removed before (you’re in for a treat), there’s an annoying bracket on the back which has to be removed. It attaches from underneath the P72 intake manifold to the backside of the engine block, as a support bracket for the heavy OEM P72 intake manifold. You don’t need to use it on the Skunk2 intake manifold if you don’t want to.
14. Next get underneath your car so you can see the underside of the GSR manifold and the support bracket
15. Use a ratchet with a long extension to reach the two 12mm bolts and remove the support bracket.
16. While you’re under there, you can disconnect any sensors or hoses etc… that are still connected to the P72 intake manifold , such as the IAB sensor (black-round canister mounted on the underside of the GSR manifold). Loosen and remove all the 12mm flange nuts that are holding the P72 manifold to the head from underneath too.
17. Then remove the rest of the 12mm flange nuts from the topside of the P72 inlet manifold
[ Preparing the Skunk2 intake manifold]
18. Once you are done removing all 12mm flange nuts, double check that all sensors, vacuum lines, and any coolant lines are not connected to the P72 manifold
19. If everything looks ok you are good-2-go, carefully remove the P72 manifold.
20. Once removed, with a 12mm socket, remove the throttle body housing from the P72 manifold and very carefully peel the throttle body gasket off using a razor blade or scraper. You want to try and preserve the throttle body gasket and reuse it.
21. Next, you will prep the Skunk2 intake manifold, by swapping over the P72′s fuel rail, throttle body mounting posts, and required sensors
22. You can start by removing the standard P72 fuel rail mounting posts by using two of the 10mm fuel rail nuts.
23. Next are the throttle body mounting posts. Remove and apply these posts using the same technique as used on the fuel rail posts
24. Next is the sensors. Swap over the IAT and IACV sensors.
25. Then apply the ITR throttle cable bracket.
26. Lastly, swap over the rubber fuel injector grommets onto the Skunk2 manifold.
[ Throttle Pulley Swap ]
27. Now that you’re temporarily done with the manifolds, it’s time for throttle body procedures!
28. Now, I’m assuming you’ve acquired a non P72-GSR throttle body pulley. If you haven’t done so, get one!
TIP: Almost any 88-01 civic/integra NON P72 throttle pulley will work on a P72 throttle body
29. Using a 10mm socket to remove the P72 throttle body pulley. Then apply the NON P72 throttle body pulley.
Note: You *might* have to fiddle around with remounting the retention spring a bit, but its not hard to figure out.
30. Next,you can remove the big P72 throttle cable supporting bracket that’s directly on the P72 throttle body.
31. The P72 throttle body is now ready — wer’e just about there.
32. If you’d like to, you can mount the prepped P72 throttle body onto the Skunk2 intake manifold now. Reuse your P72 throttle body gasket if you haven’t completely damaged it!
33. Now, install the Type-R throttle cable into your vehicle. This is pretty straight forward, so i won’t go into the procedure of this.
[ Preparing the PCV Valve ]
34. Once you’ve finished installing the type-R throttle cable, go back to your engine bay and have a look at the area where the intake manifold support bracket lives.You will see the standard oil catch can with 2 lines that are plugged into the top of it. This is the location of the PCV valve.
35. Once you’ve pulled out the PCV valve, get a long vacuum tube and attach it to the PCV valve. Then plug the PCV valve back into its respective location (for a test fit).
36. Now, take the pre-prepped Skunk2 intake manifold and place it on the head in its final position. Slip the PCV tube up and in between the manifold’s runners till it reaches the vacuum spout in the middle of the plenum.
[ Finishing Touches ]
37. If the PCV tubing seems like it is going to be long enough without kinking or binding problems or anything of that nature, its ready.
38. Check to see if all the coolant lines can be put back into their original locations. I usually bypass the coolant lines that run to the throttle bodies fast idle throttle valve (FITV), that is located underneath most throttle bodies. Although, if you live in a cold weather climate zone bypassing the FITV is not really a good idea.
39. Once you have looked over all your coolant routings, tighten down all of the 12mm flange nuts to the specified factory torque (that is, if you can reach a torque wrench down into those tight spots)
40. Apply the P72 throttle body to the Skunk2 manifold if you haven’t done so yet
41. Fit the coolant lines and PCV valve back to their respective locations
42. Now it’s time to reinstall the fuel rail and injectors. Use the 10mm nuts to secure the fuel rail to the fuel rail posts, then connect the fuel pressure regulator vacuum hose.
NOTE: The brown ceramic spacers that sit between the fuel rail and manifold are NOT USED. To check this, make sure that there are no loose gaps between the fuel injectors and the fuel rail. If there is any gap and the injectors sit loosely, remove the ceramic spacers! or else your fuel injectors will leak, and because those ceramic spacers are not used, the fuel rail will now sit lower on the mounting posts, and you may have to elongate the mounting holes on the fuel rail to comply with the mounting posts. You’ll see what I mean…
43. Connect the throttle cables’s hammer-end into the throttle pulley; then mount the cable into the throttle-cables bracket. Make sure that you’re getting full throttle travel too. Have a friend in the car to push the gas pedal up and down and look inside the throttle body to see if the brass butterfly inside is opening all the way. Adjust the throttle-cable as necessary if the butterfly isn’t opening all the way
44. Re-connect all of the sensors (IACV,IAT,TPS,MAP, etc)
45. DON’T FORGET: To tighten down the 12mm fuel pressure release nut on top of the fuel filter!
46. Re-tighten the fuel cap.
47. Refill your radiators coolant , with new coolant or you can reuse your previous coolant if it has been saved.
48. Double-check that everything is connected and OK, looking good, etc.
49. If all is good, get in your car and turn your ignition on 2 clicks then wait and listen for the fuel pump – but don’t start the engine yet! This will build up the fuel and pressurize the system. Leave the ignition on , then go check your engine bay to see if there is any spray or fuel leaks coming from the injectors, fuel rail, or fuel filter. If everything was put back correctly,there shouldn’t be any fuel leaks, vapor or fuel spraying of any kind. If no leaks – so-far-so-good!
50. Now, turn the ignition to the (3rd click)to start the engine. It may take a few turns of the engine but don’t worry, it’ll start.
51. Once running, check for coolant leaks etc, if all looks good you’re install is a success!
51. If you have any high or irregular idle problems, double-check any vacuum lines or any unplugged sensors. Try playing around with the settings of the idle-adjustment screw on the throttle body.
53..Lower the car back down to the ground and go for a test drive, there should be a noticeable incease of horse-power.
54. Clean up that mess before the misses kicks you in the butt!!
ADDITIONAL INFORMATION By now, you should know that a Skunk2 Intake Manifold uses a single-butterfly design, and an OEM P72 intake manifold uses a dual-butterfly design. A stock P72 ecu doesn’t know that you have changed over to a single butterfly style intake manifold, and seeing that the Skunk2 manifold is essentially a Type-R manifold, you’ll need to adjust your ecu for this change. Mainly, the VTEC crossover point needs to be raised.
Here’s a few options:
- OPTION 1)
You can run your stock GSR ecu as-is for the time being, but peformance wise, it will not feel right with the stock VTEC crossover point kicking in at approx. 5000rpm…so..
Installing a VTEC controller is suggested, so you can raise the VTEC point up to about 5500-5700rpm …or…
Have your ecu reprogrammed (chipped). If you have an OBD1 P72 ecu you can have it reprogrammed with a customized VTEC, redline, & fuel maps. If you own an OBD2 vehicle, I would suggest converting to OBD1 or running a Type-R ecu. Although, if you go with this route, I suggest that you upgrade your camshafts to at least civic or integra type-R cams (you don’t have to – its suggested though). Actually, you should really upgrade your camshafts anyway, to benefit even more gain and horse-power from the Skunk2 itake manifold upgrade!
Skunk2 manifolds can be purchased by visiting www.motorcaraccessories.com/skunk2pro-series