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the HX is a special lean burn engine that generates really good gas mileage. EX is deluxe version with slightly bigger engine, bigger tires, moonroof, antilock brakes, etc. check honda's website for all details. chicks dig the ex [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

 
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But the EX and HX both have Vtec motors and both have the same compersion ratio but the EX has more horses[IMG]i/expressions/face-icon-small-confused.gif[/IMG]

 
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i thought the ex was the only one with vtec[IMG]i/expressions/face-icon-small-confused.gif[/IMG]

 
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thats what i thought

 
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yeah, that seems odd to me also. But i think it has something to do w/ the tuning. Just how the older Si's has 160 and ex only has 127. The ex has less restrictive exhaust and stuff like that.....and i think the VTEC in the EX is engineered to generate more horses when it kicks in than the HX, which is engineered more for mileage....its just a perk of having the deluxe model, basically.

 
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What i really want to know is since all these turbo kits are being designed to fit the EX will it fit on the HX model since it is pretty much the same set up. I bought the greddy EVO exhaust system (cat back) which is made for the EX and it fit fine on mine. I have allways herd the the EX's cat is located in a different area than all the other models, but if that was the case then the EVO would of never fit on my car, so which leds me to the conclusion that most products made for the EX should fit on the HX.

 
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The VTEC-E in the HX is exactly the same in fuction as in the EX. The HX merely adds the ability to lean burn:

2002 Honda Civic DX: 1.7L SOHC 16-valve I4 ULEV-certified engine (D17A1)
2002 Honda Civic LX: 1.7L SOHC 16-valve I4 ULEV-certified engine (D17A1)
2002 Honda Civic EX: 1.7L SOHC VTEC-E 16-valve I4 ULEV-certified engine (D17A2)
2002 Honda Civic HX: 1.7L SOHC VTEC-E "Lean Burn" 16-valve I4 ULEV-certified engine (D17A6)

As for intake and exhaust on an HX, think of it this way. Any intake from an EX will fit an HX. If you want exhaust, you'll need a header and cat-back plus the ability to mod the O2 sensor locations.

edit: BTW, for some reason I think the HX may even be faster in the quarter than the EX. Why? Because the HX hits VTEC at 3100rpm and will stay in VTEC for the duration of the quarter... I don't know if the EX shifts will drop the RPM below VTEC engagement. Not to mention the HX weighs the same as the DX/LX.

 
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The VTEC systems are totally different. Go Here and read up on all the kinds of VTEC. The EX VTEC alters the Cam profile to add power. The VTEC-E system closes off an intake valve at low RPMS. So when it Kicks on at 3000 or whatever, all it does is open the 2nd intake valve.

 
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If you read my above post fully, you'll notice that both the EX and HX have VTEC-E. From your link you've shown that both the cars close an intake valve at low RPMs.

edit: Now I'm confused as fvck. Honda's website says the EX comes equipped with VTEC, and the HX with VTEC-E. However, every parts and dealer site says they both have VTEC-E. I don't know what's true. Either everyone else is wrong, or Honda likes advertising the EX as a "true" VTEC...even when it's not? [IMG]i/expressions/face-icon-small-confused.gif[/IMG]

 
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Straight off that link:
SOHC VTEC
"During low RPM operations, the two outer intake cam lobes directly actuates the two valve rockers. These low PRM intake lobes are optimized for smooth operation and low fuel consumption. The high RPM intake lobe actuates the follower. But since the follower isn't connected to anything, it doesn't cause anything to happen. This procss is illustrated by the figure to the right.

At high RPMs, oil pressure pushes a metal pin through the valve rockers and the follower, effectively binding the three pieces into one. And since the high RPM lobe pushes out further than the low RPM lobes, the two valve rockers now follow the the profile of the high RPM lobe. The high RPM lobe's profile is designed to open the valves open wider, and for a longer duration of time, thus allowing more fuel/air mixture to enter the cylinder. The improved breathing allows the engine to sustain its torque output as RPM rises, thus resulting in higher power output "



VTEC-E
" A VTEC-E engine has two different intake cam profiles. At low RPMs, each intake valve works from its own intake cam profile. One of the intake cam profiles is very normal looking. The other one, however, is almost perfectly round, with just enough profile to it so that it pushes the valve open just enough to avoid pooling of fuel above the valve lip. Therefore at low RPM, only one intake valve is opening and closing. Most of the intake fuel and air are squeezed through this one valve, resulting in a good swirling effect in the cylinder. The swirling effect optimizes the fuel/air mixture, thus allowing a very lean mixture to be used.

As the RPMs increase, the demand for more fuel/air rises as well. Once a certain RPM is reached (approximately 2500RPM for the Civic HX), the one-intake-valve configuration starts to become a significant intake restriction. At this time, a solid pin is pushed through the two intake valve rocker arms, thus binding the two rocker arms into a single unit. This causes both intake valves to open and close according to the normal cam profile, while the almost-round cam profile is no longer used.

VTEC-E is some times confused to be just another high-RPM optimizing mechanism like other VTEC variants. And there is some truth to this: since only one intake valve is used at low RPMs, the one normal cam lobe is made to open that one valve slightly taller and for longer duration than if both intake valves are used. At higher RPMs, both valves follow this same cam lobe so they are both opened slightly taller and for longer duration. This results in a slight improvement in high RPM breathing compared to non-VTEC-E engines and thus slightly more power. This is evident by comparing the Civic DX and Civic HX engine. The two engines are essentially the same except for the VTEC-E in the Civic HX. But the Civic HX's VTEC-E mechanism results in 115hp, versus 106hp from the Civic DX. So the Civic HX has more power in addition to better fuel economy. But make no mistake, VTEC-E is designed with economy as the primary goal, not power output."
(The HP Ratings are from 6th gen Civics)

So regular VTEC runs 16 Valves all the time, both intake valves run all the time, VTEC-E runs 12 (1 intake,2 exhaust per cylinder), then 16. And the HX is the ONLY car with VTEC-E. The D17A2 is plain old VTEC.

 
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Wish you would have quoted my whole post...

but anyway...I posted VTEC-E for both EX and HX from a dealer's website. If you ever look for parts...AutoZone, whatever...it'll list both EX and HX as VTEC-E. I'm surprise they would make a mistake leaning towards the less common model (the HX). I've driven both an EX and HX and engagement feels the same in both. That led me to conclude that they are the same type of "VTEC". Again, I state...either Honda wants to mislead us...or dealer and parts retailers are wrong.

 
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Power-wise, it's simply the EX's exhaust manifold.

 
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What's so special about it...we all have a mini-header, the HX just happens to have it's cat right after the header.

I just chatted with Boilermaker and it may be...in fact...that the EX has VTEC while the HX has VTEC-E. Who knows...one side says this, but another says that. I guess I'm leaning toward EX=VTEC now. I'm just confused why parts dealers keep thinking both have VTEC-E.

 
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I know it was written for 6th gens, so maybe something has changed. Sometimes I get at power boost at 2500rpm (or less), but I also get another big hit at 3100rpm. Is it:

800-2500rpm = 1 intake, 1 exhaust
2500-3100rpm = 2 intake, 1 exhaust
3100+rpm = 2 intake, 2 exhaust

 
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Has anyone with an EX actually looked on the plastic cover on the top of your engine? My 02 5spd Ex, sas "VTEC" not "VTEC-E". has anyone looked at their HX engine? Does that say VTEC-E? This will probably help out some issues here. At first I thought they both had Vtec-E, by the top of my engine doesnt say that. Oh well, the label doesn't really make a difference anyway. more curiousity than anything i guess.

 
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They both say VTEC.

 
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you would think honda would put "VTEC-E" on top just like the SI "i-VTEC", if they both just say VTEC, then I'll agree on some members, they are both VTEC-E. Thats what is said every site I look up.

 
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OK, I just called Honda and left a message asking about the differences in the HX and EX engine. Hopefully they'll contact me tomorrow.

 
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Okay, straight from the specs of the 2k2 civic coupe page at Hondanews.com

The HX and the EX both have VTEC-E engines, but the HX is listed as a lean burn engine. Also, the manual tranny has different gear ratios. The compression ratio is the same.

The kicker though is that the 2k3 specs show only a VTEC engine for the EX and a VTEC-E lean burn for the HX. So maybe even Honda is confused with what kind of engine they are using.

Based off of other info though it would be safe to say that the HX engine is obviously different from the EX engine. Sure both are VTEC based and they have the same compression ratio, but the HX is designed to save gas and the EX is meant to use it.

 
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yeah i am now also very very confused....Bravo to PESTLNC for starting some research...hey pest, what's crazy is the on the Honda website....it shows the EX for 03 as being "VTEC"...not vtec-e like mine did for 2k1...weird, huh....I wonder if anything on the engine changed, as far as the VTEC components.....

 
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Has anyone gotten the final word from Honda yet? This is all so strange. I don't care so much about the names (VTEC vs VTEC-E) but I would like to know about what each engine does. For instance, does the engine in the EX (whether it's called VTEC or VTEC-E) keep one intake valve on each cylinder closed at low RPMs like I know it does in the HX?

 
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I'm pretty sure the motors are the same. The tranmission on the HX is geared lower, the exhaust in mroe restrictive, and the ECU is different. I bet if you changed those 3 things on the HX it would be the same as the EX.

 
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Ug, I got a message back from Honda: "Thank you for your interest in the VTEC engine in the Civic, however, I am unsure what model the HX is...blah blah blah"

 
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I know ignorance about the HX is widespread but for a Honda representative not to know about it?? Egad!

 
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i have a 1999 honda civic ex and someone had swapped a 97 hx motor into it and i cant get it to run, does anyone know how to make it work?

 
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did they also swap the ecu and all the exhaust parts (two cats) and the oxygen sensors? did they wire up the vtec solenoid from the new engine to the ecu?

 
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Also the HX only has power mirrors and locks, the ex has power windows and moonroof

 
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I have a 2003 ex. I had to replace the engine with a hx model. I have been into both of these engines and I can tell you the difference that I personally found. The block, crank and pistons were the same, as well as everything else in the lower end. The heads were the same also, in very detail EXCEPT....the camshaft and valve lifter arrangement. The HX valve assembly had the 2 exhaust, 2 intake rocker arm arrangement with the 1 intake being the smaller lobe that is almost round (you have to look hard to see any lobe at all), and the other intake rocker having a wider roller tip (other intake having just the solid, flat surface tip) on it. It had the pin that activates and joins the two rockers for hi rpm....now for the camshaft...the HX had the 4 lobe design.....the 2 exhaust being separated by the 2 intake. The one intake being the aforementioned almost lobeless one, with the large intake lobe right beside it. My true EX had a different camshaft, with the 5 lobes....2 exhaust, 2 intake and 1 (VTEc) lobe that was used when the 2 regular intakes locked up to the 3rd larger one and there made both intakes open the valves using (essentially) the 1 vtec lobe profile. My HX engine acted as the person describe, above, with the 1 intake operating by itself during regular driving and locking up to the larger lobe cam love during high rpm. As I said, this camshaft only had the 2 exhaust, 2 intake (1 large, one barely a lobe) arrangement. I dont know if the vtec actuation is the same for these however. I ended up using the HX engine in place of my EX damaged engine. I no longer detect a vtec (surge) at higher rpm...it does have a little umph, sure but it isn't a very recognizable thing. My opinion is that my HX engine doesn't have the same get up and go that my previous one had. Is the vtec that is in my stock system fully compatible with the HX engine? I don't know. All i know is that it will run fine if you swap out the engines. Mine is running fine for 1 year now without any problems. All these parts should hook up fine and be interchangeable....but if you want the vtec instead of the vtec-e performance (mine is getting the vtec-e using this arrangement of HX camshaft/valvetrain) you might want to make sure your ex valve train and camshaft is used. I don't know what honda is doing with its lack of useable information from dealers and other sources but some friends i know at a local dayton ohio honda tell me it all starts from honda Japan. The rumor is that they aren't very forthcoming to the U.S. repair market...why? I dont know. So...all i can say is pull the valve cover off, count the camshaft lobes and rocker arms and go from there.