I see that a lot of you guys do the 2.3 ho intake manifold swap. Why is this manifold any better then the stock manifold. Also what needs to be modified on it to make it fit the 2.4? Whats the gains?
http://www.overkillengineeringmotorsports.com/
I just got done my swap about 2hrs ago...It has a deeper tone and past 3500 rpm there is a noticeable difference. I have heard with a bigger throttle body and freeer flowing exhaust it really brings this mod to life. People do it because, its metal not plastic(better for boost), its a better design and larger runners(more hp), and it just looks good under the hood. Its not that hard to instal but there is some custom work, it took me and a friend about 5 hours but that was including modifying the manifold and throttle body and fixing a few other clearance issues. Do a search for HO manifold swap and you will find links to detailed instructions..
The benefits of the HO manifold are geared more towards boosted motors and the higher RPM NA builds because it is a log style manifold with a much larger plenum, as well as shorter runners. No one has yet to invest any time/money into dyno runs to see if they gained anything after the swap on a stock motor. When I was completely stock, it felt like I was making more power in the upper end, although butt dynos can be a mysterious thing sometimes.
To make it fit, you either need Fontana's adapter flange or you have to port match. In order for the port match to work effectively, though, you would have to port both the manifold and the head. There are als 4 bolt holes that have to be dremeled a little bit to clear the lower bolt holes on the 2.4L head.
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"Youth in Asia"...I don't see anything wrong with that.
Brian Whalen wrote:The benefits of the HO manifold are geared more towards boosted motors and the higher RPM NA builds because it is a log style manifold with a much larger plenum, as well as shorter runners. No one has yet to invest any time/money into dyno runs to see if they gained anything after the swap on a stock motor. When I was completely stock, it felt like I was making more power in the upper end, although butt dynos can be a mysterious thing sometimes.
To make it fit, you either need Fontana's adapter flange or you have to port match. In order for the port match to work effectively, though, you would have to port both the manifold and the head. There are als 4 bolt holes that have to be dremeled a little bit to clear the lower bolt holes on the 2.4L head.
Sorry, I meant completely stock
with the HO manifold...big difference
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"Youth in Asia"...I don't see anything wrong with that.
No one has PROVEN with before and after dyno's. It SHOULD make more people. You will lose some torque, but will gain HP in the upper RPM's. Which is better, all depends on the other mods of the car. I would classify the HO manifold swap as a supporting swap, not a direct increase in performance. It should work great with a nice set of cams and a port-n-polished head.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
You will def feel more pull above 3500, its an easy swap. And for losing torque its not noticable.
Has any one had this problem where there manifold only had 1 vac. port on the front of it? Mine has the 2 in back and 1 in front . will this couase problems down the road when i hook it up and what can i do to get it to work a t fitting vac. line?
go to any of the auto part chain stores and get a set of vacuum caps. they're little caps for those ports.
supercharged 2.4L alero
www.cardomain.com/ride/2168613
OnEBaDAzZz24 wrote:Has any one had this problem where there manifold only had 1 vac. port on the front of it? Mine has the 2 in back and 1 in front . will this couase problems down the road when i hook it up and what can i do to get it to work a t fitting vac. line?
You should have 3. One is for the MAP, another is for your FPR and the last one runs to the inside of the car. The only vacuum holes you should need to cap are the ones on the 2.3L throttle body if you are using it.
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"Youth in Asia"...I don't see anything wrong with that.
Brian Whalen wrote:OnEBaDAzZz24 wrote:Has any one had this problem where there manifold only had 1 vac. port on the front of it? Mine has the 2 in back and 1 in front . will this couase problems down the road when i hook it up and what can i do to get it to work a t fitting vac. line?
You should have 3. One is for the MAP, another is for your FPR and the last one runs to the inside of the car. The only vacuum holes you should need to cap are the ones on the 2.3L throttle body if you are using it.
You need to cap off the hole on the back of the plenum closer to the throttle body side of the manifold.
-the LO manifold was Dynoed here and showed a 11hp increase with the 56mm TB. OVER the stock plastic mani and 52mm.
My Cav
I give up...
i'm buying a VW those people love trees, so they should love eachother too... "Andy"
Im sorry i ment to say theres only 1 vac. line on the front of the mani and one on the back side of the mani. on the front i was told to use aT bar vac. fitting is this right?
Does this look done right?
I just did this swap tonight and at idle it sounds like its missing, but it is NOT.
When I took it for a test ride, it is a VERY noticeable difference from the stock intake.
My perfromance includes, Koni red struts with Ground Control coilovers, from and rear eibach sway bars with tie bar for the rear, rear strut brace, sub frame brace, stock header downpipe cat, then 2.25 piping to a Ravin' muffler, custom intake, I have NO raspy sound at all, honestly it sounds like a v8 camero or mustang.
When I start in first it feels like I am shifting faster into second because of the the power and tourqe difference, then 2nd gear it has HUGE sound and pull at around 3000-3500rpm
same goes with the rest of the gears, once I get mine tuned tomorrow I will let you know more about it and how it sounds with a short video
definitely a mod that needs to be paired with exhaust and tb for results.
It will (in theory) increase high-end horsepower but will have a slightly less desireable effect on the low end.
^^ there are some quirks with that mani that's rarely discussed in terms of the installation.
Like your throttle cable loks a little stressed in that pic.
Also,
From the pic, can't tell if its HO or LO, we'd have to see the thickness of the plenum under the runners.
-M
Remember....syringes go in the RED waste basket.
Heres mine....It deff. makes the underhood look better. But if your not running boost or a header with a good exhaust and cams....then dont get the High Output version manifold...just get the regular non High Output manifold cause you will loose noticable torque. I love the way it sounds and looks. Lots of mods though needed to get her done. Which includes hoses, tbody, throttle cable, and most important getting it to fit the 2.4 head without it leaking vaccum.
heres the flange I got to get welded on
GMR has got nothing on this
^^ Nice intake on that.
But, where's the rest of the manifold that went with that flange?
-M
Remember....syringes go in the RED waste basket.
this has been dynod to show a 10 hp loss. some ppl on here made up excuses on why it showed a loss.
but with my experince. i gained nothing in the 1/4 with this manifold on. if i still had the stock manifold i would put that back on

Im a Xbox 360 fanboy...and damn proud of it!!
99redz24 wrote:this has been dynod to show a 10 hp loss. some ppl on here made up excuses on why it showed a loss.
but with my experince. i gained nothing in the 1/4 with this manifold on. if i still had the stock manifold i would put that back on
I installed the LO manifold and tb on a club members 2.4 AUTO...the car was very consistant on the track( being an auto and all)the car has simple bolt ons,header,mounts,cai etc...but never got lower than a 15.9 on the track..he tried several times...i did the intake/tb for him and now he runs 15.6-15.7 consistantly ...that was the only thing changed...now mind you i gasket matched the intake best i could before install..and maybe having the other mods helped...and no we never dynoed the car before so i didnt see a reason to do it afterward...but a consistant lower time at different tracks on different days leads me to believe that the intake did him some good...but i still believe the LO manifold tb combo is the best to use NA.......
so.... which throttle body are you guys using ? custom or 2.3? iv had a LO manifold under my bed for over a year already ..
i used the matching 2.3 throttle body with the LO intake....and dont forget to grab the throttle cable bracket that comes with the intake or youll have to fab one up(not too hard) and if you dont use the flange try to match the gasket and intake to the port on the head
by matching you mean trim the gasket?
yes...but the flange is still the best way to go..only use the triming way if you cant get a flange
scott (section8cav) wrote:but a consistant lower time at different tracks on different days leads me to believe that the intake did him some good...but i still believe the LO manifold tb combo is the best to use NA.......
lower times at different tracks on different days can be helped by track elevation, track prep, track conditions, the air, etc etc.
when i was racing the cav at the same track one week i could get a 16.6 and the next week a 16.1. i went to a track down in Maryland once since it was closer to sea level. i was a half a second faster in the 1/8 mile at that track (they went to 1/8 mile cause of weather) than i am at my home track.
so becuase you did his manifold swap and got lower times at different tracks on different days doest really mean you gained power

Im a Xbox 360 fanboy...and damn proud of it!!
no..YOU said you did the swap and didnt gain ANY time in the 1/4.....i did the swap and the very next trip to the track saw a lower time..and saw the same gain trip after trip...getting the same consistant lower times at EACH different track..thats how i know its not just one better track over the other