2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

TII hoodscoup mod

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Old 07-03-04 | 06:48 PM
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TII hoodscoup mod

I've been reading a lot of post about high heat in the TII with front mounts.. after doing some research, i belive that a small part of the problem may be the stock hoodscoop.

if you put a front mount it, you've now restricted the airflow to the radiator. Further, if you leave the stock hoodscoop on, you would think that it would pull cold air into the motor and cool it.. Well, thats the problem.

During forward motion, the hoodscoop IS pulling air into the motor compartment... problem is that it dumps out right on top of the UIM, not where the hoodscoop actually is because of the tunnel in the hood. This creates an areai of high pressure inside the engine compartment, and further restricts air from comming in the front where the radiator and oil cooler are!.

Solution.. 1 is a louvered hood scoop from re amimiya... for 400 bucks!!! NOT.

another is to use the hood riser plates for sale on aerodyne.. .. maybe, ,but i hate the way it looks.

third.. aftermarket vented hood... maybe next year, no cash now..

MY solution.. remove the weatehr stripping at the top of the firewall top allow air to be pulled out the back of the hood and modify the stock hoodscoop into a reverse cowl to pull air out of the engine bay by vaccume when the car is at speed.

I', goint to make a plug out of structural foam and then use that to make a figerglass part to fit on top of the iriginal hoodscoop that covers the open area an raises over top of the rinser on the back about an inch. I'll then JB weld that cowl onto the original hoodscoop insert and use another layer of fiberglass to bond it to the edges. basically it will end up being similar to the shaker style scoops seen on older muscle cars that were designed for the same purpose, to draw air out through the hood while the car is at speed.

the original hoodscoop insert has already been modified to allow more air out by cutting vent slots into it in the area where the hole is that it sits over on the hood.

as soon as i figure out why i can't get into my website, i'll post some pics of the build.

Last edited by YearsOfDecay; 07-03-04 at 06:51 PM.
Old 07-03-04 | 08:05 PM
  #2  
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how about an n/a hood. a steelie can be found dirt cheap and aluminum ones arent too bad either if you keep your eyes out for a deal. also helps the sleeper look which is always a plus in my book.
Old 07-03-04 | 08:50 PM
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when you male the plut get a MOROSO decal for it, seriously plugging it might be a good idea
Old 07-03-04 | 10:55 PM
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Re: TII hoodscoup mod

Originally posted by YearsOfDecay

MY solution.. remove the weatehr stripping at the top of the firewall top allow air to be pulled out the back of the hood and modify the stock hoodscoop into a reverse cowl to pull air out of the engine bay by vaccume when the car is at speed.
cowl induction hoods bring air INTO the engine bay. not out. they collect air that bounces off the windsheid.

your reverse vent needs to be near the front of the hood to let air out.

Last edited by Scott 89t2; 07-03-04 at 10:57 PM.
Old 07-03-04 | 11:08 PM
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From: eugene, or
precisely... other thing you can do is leave the stock scoop on... look at the.. the flate piece of plastic that is part of the scoop. cut that rectangle open straight through and the metal behind it you can sand the edge of the plastic to make it look good... Panspeed does this with one of there cars.. works wheather you have a top mount or not... lets out hot air right behind the fan, infront of the alt. pully......

hell i got a friend that just pulled the scoop plastic and cut all the metal behind it.. then cut/cleaned the lip around the the opening with no top mount it looks o.k. a little cheap but hey the jap hood are expensive....

Last edited by astrochild7; 07-03-04 at 11:11 PM.
Old 07-04-04 | 12:57 AM
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Originally posted by astrochild7
precisely... other thing you can do is leave the stock scoop on... look at the.. the flate piece of plastic that is part of the scoop. cut that rectangle open straight through and the metal behind it you can sand the edge of the plastic to make it look good... Panspeed does this with one of there cars.. works wheather you have a top mount or not... lets out hot air right behind the fan, infront of the alt. pully......

hell i got a friend that just pulled the scoop plastic and cut all the metal behind it.. then cut/cleaned the lip around the the opening with no top mount it looks o.k. a little cheap but hey the jap hood are expensive....
i wanna see a pic of this... photoshop... real deal... what ever. I wanna see what your taking about doing.

im gonna search for the panspeed fc but i doubt ill find it.
Old 07-04-04 | 01:24 AM
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Jaared do you know what game that video was done in?
Old 07-04-04 | 03:01 AM
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Have you done any pressure testing to prove any of your theories? You might be surprised what you find. It is very difficult to predict pressure variances in and around moving vehicles just from looking, particularly in engine bays. Your initial assumptions can often be quite wrong...
Old 07-04-04 | 03:06 AM
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The hood scoop is too far away from the windshield to create a cowl induction effect. Removing the weatherstripping on top of the firewall may be a bad idea, as this may lead to a cowl induction type effect where the hood meets the windshield.

as far as a flat hood... no venting whatsoever.. not an improvement.

I placed a mockup of the modified hoodscoop on top of a box with a dreager smoke generator in it in the exhaust passage of my polishing/ painting room. (downstream of the fan to rule out vaccume effect from the fan) to simulate the car traveling at speed. the higher the fan speed, the more smoke was drawn out the back of the scoop into the airstream. I am aslo assuming that Mazda engineeers placed the hoodsoop there after windtunnel testing to be sure that the scoop would be recieving a steady flow of air and the front of the car wouldn't be deflecting it up over the hood.

this works the same way as the vaccume port for the power brake booster in the UIM does.. an opening that faces AWAY from the airflow will see a negative pressure, this is how you can get vaccume for your brakes even under boost conditions. As air travels up over my hood it will hit the hoodscoop cowl and be forced to rise to get over it rather than being forced into the hole. this will create and area of low pressure at the top of the cowl, thus drawing air out of the engine bay, through the hole beneather the insert and through the tunnel for the TMIC. the windshiled is a good foot and a half back from the insert, ans will not interfere with this effect.

I guess the real test would be to place the smoke generator in the hood tunnel and take the car out on the road to see if smoke is drawn out the louver/cowl, but as the engine isn't in the car.. that aint gonna happen for another week or so!!

Basically, this thing is going to be one huge hood louver instead of a lot of little ones.

I wish i could post a pic of whats going on, but VERIZON is being a bitch and i can 't modify my website for some reason....

Last edited by YearsOfDecay; 07-04-04 at 03:26 AM.
Old 07-04-04 | 03:15 AM
  #10  
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Ok so will I see negative effects swapping the N/A steel hood to a TII hood on a N/A seeing as how I already pulled the hood off a junked car?
Old 07-04-04 | 03:19 AM
  #11  
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rx7.com USED to have the RE amimya louvered hoodscoop pictured on their website, but they stopped carrying it because the pricetag was retarded and nobody was buying it at 400 buck a pop!~!
Old 07-04-04 | 03:21 AM
  #12  
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flamin roids.. I don't know.. being that you don't have a FMIC to slow down the airflow into your car, i don't think so, but, you will find grasshoppers and such smashed onto your UIM!!!!
Old 07-04-04 | 03:25 AM
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Well I've thought of that but seeing as how I have the hood and go it for free and its tons lighter than my steel hood. I'm just wondering if there will be any negative drag or air flow.
Old 07-04-04 | 03:28 AM
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Slight bit of drag, but nothing to worry about, the wieght savings will make up for it.... Put a piece of mesh over the opening on the underside of the hood... this willl keep cicadas, rabbits and leaves from splattering on your engine!!!
Old 07-04-04 | 03:30 AM
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Cool. But the real problem is I'll have a TII hood along with TII rims on a GXL so I'm going to have problems with people kicking my *** and then telling their friends they beat a turbo 7.
Old 07-04-04 | 03:45 AM
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Well, at least you don't have a sick Turbo II that got beat by a civic last fall and caused you to rebuild it, port it, get a new turbo, ,a haltech, and about 2 grand worth of other hops ups to quell your shame!!!!

Hey... Just don't race them and they'll never know!!! or put some NOS on that bad boy!!
Old 07-04-04 | 03:48 AM
  #17  
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Hmm. I having the car painted this fall so I think I'll replace the GXL on the side with GTUs so I can easily convince others it isn't a turbo. Also the breather hissing after revving doesn't help either.
Old 07-04-04 | 04:03 AM
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Originally posted by NZConvertible
Have you done any pressure testing to prove any of your theories? You might be surprised what you find. It is very difficult to predict pressure variances in and around moving vehicles just from looking, particularly in engine bays. Your initial assumptions can often be quite wrong...
... as well as the assumption that there is too much heat in the engine bay, or that a few extra degrees in the engine bay even makes any significant difference in performance.

I like how everybody tries to solve problems that don't exist or don't matter. Just so I don't feel left out, I am currently working on the following projects:
1) Evil Windshield Washer Fluid Cooler - It's a small air-liquid heat exchanger that keeps the windshield washer fluid from boiling, adding 15hp to the engine because the increased efficiency of the washer motor with the more dense fluid charge eliminates cavitation, reducing the load of the alternator.
2) Evil Plasma Ionic Nose-Charger - This special grounding strap charges the plastic front end with negative ions, lowering the coefficient of drag by 0.02, which increases the top end of the car by 20mph. It works just as well as an Ebay electric supercharger.
3) Evil Cold Air Intake - It's actually just a stock intake, but since the stock intake is a cold air intake, I can charge a lot of money for this just by changing the name.
4) Evil NA Intercooler - Guaranteed to cool the intake charge down to ambient temperature on an NA 13B. This is good for 350hp (with optional $10,000 turbocharger kit).
5) Evil Super Reduction Pulley - Special alternator reduction pulley reduces engine load and increases the life of most electrical system components (except the battery) because it goes off-line below 3000rpm. This is even better than the other reduction pulleys on the market that only make the alternator go off-line at 800-1000rpm.
Old 07-04-04 | 04:09 AM
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Dude..... you are evil...

and just for the record.. Heat is baaaaadd Mmmm-Kay.
Old 07-04-04 | 04:12 AM
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Originally posted by YearsOfDecay
Dude..... you are evil...
Yup.

Originally posted by YearsOfDecay
and just for the record.. Heat is baaaaadd Mmmm-Kay.
Please explain.
Old 07-04-04 | 04:20 AM
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Originally posted by YearsOfDecay

and just for the record.. Heat is baaaaadd Mmmm-Kay.
Don't you know your physics? Heat has and is energy and enegry makes a car go. So the more heat, the more energy going thought the car, adding 'mo powah'.

Anyway, what about using the stock scoop, only upside down?





Old 07-04-04 | 04:21 AM
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^^soul assassin's old car.
Old 07-04-04 | 04:37 AM
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Originally posted by version13
^^soul assassin's old car.
may it rest in pieces.

edit: i seem to recall a piece made for the factory t2 hood scoop that would replace the inserted piece (the forward facing scoop) with a 2 louver (i think) reverse scoop piece. get it painted to match your hood and it looked pretty clean. someone bought one and had lots of pics up...but it was awhile ago and i can't remember who or find it in a search.

Last edited by bingoboy; 07-04-04 at 04:42 AM.
Old 07-04-04 | 08:32 AM
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Originally posted by YearsOfDecay
I placed a mockup of the modified hoodscoop on top of a box with a dreager smoke generator in it in the exhaust passage of my polishing/ painting room. (downstream of the fan to rule out vaccume effect from the fan) to simulate the car traveling at speed.
There is no way that will accurately simulate a car at speed. For starters, you're missing the car, so you'll be getting quite different results. To do this properly, you need to do your testing on a moving car. If you're really serious about it, subscribe to AutoSpeed and read these articles. They cover exactly the ideas you're playing with.

http://www.autospeed.com/cms/A_2159/article.html
http://www.autospeed.com/cms/A_2160/article.html
http://www.autospeed.com/cms/A_2162/article.html

this works the same way as the vaccume port for the power brake booster in the UIM does.. an opening that faces AWAY from the airflow will see a negative pressure, this is how you can get vaccume for your brakes even under boost conditions.
Ah no, not even close. The brakes get their assisitance from manifold vacuum, and only then the throttle is closed. There is never brake assistance under boost.
Old 07-04-04 | 01:50 PM
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From: eugene, or
there has been a pic of a 2nd gen in a wind tunnel circulating around i'll see if i can find it.. it shows that no air is hitting the hood at the scoop.. its all pulling up or away there .... i know it will cause alot of ****, but i think the air flows backwards through the scoop, up from the tranny...



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