fcdrifter13

Chalk up another GTUs that has went the way of The Slow and the Curious Vermont Drag

blacks5

Thanks.

blacks5

What do you mean by "chalk?" Sorry i dont understand your slang, but where is drag racing mentioned anywhere in this posting? It is not the same as autocross just so you know.

blacks5

Now i understand what you were trying to say after sgt. pepper explained it.

robtechfabrications

i understand where everyones comming from on the leaving the GTUs stock...but i look at it like this..its not a freakin 63 corvette stingray, it's not really going to be worth assloads of money someday...if i had a GTUs i'd do the same thing im doing with my NA now...gut the hell out of it and set it up for track abuse...not all of us want our cars bone stock just cuz its rare car...i have my car cuz i love driving and i have more fun driving a lightweight lowered car than a bone stock s5...

robtechfabrications

and the 5one5 hood mentioned above isnt ricey...it's functional...ricey would be if the vents had absolutely no performance gain...but they do so its very functional.

blacks5

Oh, and from what i hear, only 1100 were made in 1989 and another 100 in 1990. Only 10% of all of those are black from what i hear. BTW, who are you to tell me what i do and dont know. I guess im not a "knowledgeable" owner like you, but from my posting how do you know me well enough to believe that i dont know anything about a GTUs? From what you are saying, since i know what i have, i should park it in my garage and never drive it? Whats the point of owning a car if you are not going to have fun driving it? Im not trying to be an *** either, im just telling you how it is for me and my car, and im not telling you how it is for you and your car. Can we please leave it at that?

blacks5

I also understand where they are coming from. I have my car for the same reasons you do. Driving should be fun, so i feel i should be able to have fun in my GTUs the way i want to have fun, and not how others want to have their fun (such as keeping it in a garage and admiring it). If this car is sooo rare, why did i get it for less than the cost of my beater civic? We all have our own intentions for our cars. Please be respectful of those intentions by not telling others what they "should" do. Thanks for the posting robtechfabrications.

'87 turbo II

iTrader: (1)

I had it in my head I just said Ricey to save my lazy *** some time and let someone else explain.

blacks5

I see. Well, i do understand why you said what you did. The GTUs is the rarest model fc in the US, if not the world (? Please let me know if there was a model that had fewer production numbers) and i do appreciate it for what it is. I just have so much fun driving it, imaging it even lighter gives me a high like none other. I would be up for a trade if i felt the t2 was is as good condition as my GTUs (which is very clean for being completly stock in my opinion. Almost perfect interior, no major dents on body and the paint is clean, but not perfect, original engine with 118k and no major mechanical issues or rust. Striaght frame with a Clean California title. located in the Bay Area.) I am not looking since i am happy with what i have, but if you feel that what i plan on doing is going to an fc3s member tradition, help me out instead of simply telling me what you think. I appreciate all the information this thread has given me (i dont plan on using a t2 hood as a result of the informed advice given). I know i will find this web site as beneficial in the future as well. Thank you all.

ProjectR13B

iTrader: (1)

corksport sells a rear hatch now i believe. i was looking for the same mod since i already have an aluminum hood and i ahve one of the heavy *** RX-7s now.... 90gxl haha

MazterDizazter

iTrader: (5)

It's not like you're talking about hacking up the body or doing irreversable things to the car. The interior can be put back in and the original hood can be put back on. Why's everyone whining? I gutted my TII and I keep all the parts that came out of it in my garage so I can put 'em back on if and when I need to. I did the same thing with my MR2 and my Lumina (yes, I said Lumina....sigh) before that. Do what you wish, it's your GTUs.

MazterDizazter

iTrader: (5)

If gutting the interior is the most useless mod in the world, then why do all professional race cars not have full carpets with sound deadening and stereos? Because lighter means faster. The old racer mantra is something like "worry about the ounces and the pounds will come." The carpeting and insulation in an RX-7 weighs close to 30lbs. And it's a free mod. I think (although I'd still do it if I had the money) that buying carbon fiber parts for a car is a foolish mod because the cost versus benefit is so much lower than putting the same amount of money into power-adders or suspension/brakes/tires. But losing 30lbs for $0, you can't beat it.

blacks5

Exactly my point. Thanks for the posting.

raptor22

Here's my take on the whole turboII hood thing. The increased inlet area will decrease aerodynamic drag and increase the airflow through the engine bay. It will also help the cold air mix out to distribute cold air through the engine bay. Therefore, it will decrease engine bay temps.

Here is a great post pulled from another forum by the all-knowing ( ) Dr. Mark Drela. You probably don't know him, but he is famous in many other hobbies/industries. He is a professor of aerodynamics at MIT and designed the XFoil aerodynamic code:

However, it WILL, as stated, decrease the airflow through the radiator due to a higher engine bay pressure. However, considering that most hood scoops aren't massively efficient, I would guess that the pressure effect may not be too large, but I may eb wrong on that.

I guess the biggest question is whether the lower engine bay temps or increased flow through the radiator have the biggest impact on total engine temperature.

Here's an idea: If the hood scoop reduces under hood temps and increases pressure, it would therefore increase the mass of air entering the engine and increase power marginally, no?

--Alex

raptor22

cause professional racecars don't drive on the street or do anything besides race. Its not like you are going to notice 35 lb's; if you drive the car ont he street much, its a stupid mod. Now, if its a track-only car, that's different.

BTW, I agree with everyone else about not gutting a GTUs. It honestly wouldn't surprise me if they are someday worht alot of $$$, and why trash a rare car for no damn good reason?

To me, that is like burning expensive wood like ebony when there is oak all around and saying, "why not? its my wood and I want a fire"

--Alex

blacks5

I agree with you also. "Trashing" or "messing up" this nice of a rare car is not a wise move. But thats the thing though. I DONT plan on trashing it. I treid to make myself clear on that point, but here i go again. The only mods i plan on doing are those which are easily reversable. I dont even plan on putting wider wheels on it since i will have to roll the fenders which would be the worst thing i have mentioned in terms of "trashing" the car and modifying it from its stock look.

MazterDizazter

iTrader: (5)

As far as the TII hood goes, that argument does make sense, but you'd really have to test it and not just speculate. However, if it is true, perhaps all the people who switched to front-mounts should consider going with a non-vented hood. But that's not what the argument is about anyhow....

'87 turbo II

iTrader: (1)

more aire WOULD enter the engine but not in the right area. Cold air hitting hte top of the block would be un noticably coling but the robbin gof air passing through the radiator which needs air more WOULD be noticeably slower. It may ad a bit more airflow but in the wrong ares which also decrease from the areas you DO want the air. A reverse vented hood is like a vaccume though and that'd bring air through the radiator quickly.

raptor22

I realise the argument that everyone posted. I acknowledged it in my post. Please read it more carefully before you try to explain it all to me...it includes alot more information than what you quoted.

You don't understand the quoted statement. I said in that sentence that more air enters the ENGINE, not the engine bay. By decreasing bay temps and increasing under-hood pressure, you will increase the mass of air entering the intake, and effectively boost the engine marginally.

I honestly wouldn't think the pressure difference is large enough to make much difference to anything on a n/a, considering the size of the scoop. I just wanted to post the other side of the story, since there are also arguments to be made FOR addictional engine cooling, increased power, and decreased aerodynamic drag with the addition of the scoop.

--Alex

raptor22

Here's the best way to visualise my argument about the engine temps. Don't think of the scoop as something that is squirting air onto the top of the engine; I really don't think that is the case. I think it is more along the lines of the air slowly diffusing through it into the engine bay. This would improve the diffusion of all cold air, and effectively make all of the air in the engine bay cooler. Plus, air flowing backwards from the engine bay would be cooler, and as posted, could help cool the transmission more. Finally, during city driving, the scoop would ideally suited to allow extra hot air to escape the engine bay.

So, which do you think is more benificial? A tiny bit of extra airflow through the radiator, or the engine bathed in noticeable colder air? For the sake of argument, I am saying the second one.

--Alex

'87 turbo II

iTrader: (1)

Ok now I see what you're saying. Ok put it this way, if the air entering the engine bay is comming in at 2 areas (front and back) then the backpressure would creat something a bit close to equilibrium and the air would become stale. This air sitting in the engine bay would exit in 2 ways, 1) being sucked into the intake and 2) through the open bottom of the bay.Well "air" in terms of physics, has a low absolute temperature, a better way of saying this would be that non-moving air can change temperature very quickly without absorbing much energy(if the air heats up it's not taking too much energy from the engine to cool it down) in the simplest of terms, cold air with backpressure and equilibrium would not saty cold for very long. Then the hotter parts of this air (heated by and engine that is already running hotter from a insuffecient radiator) would rise and all the colder air would go out the bottom and expectedly cool the transmission (this is probably the effect our members see). this hot air would then be sucked into the intake and the hotter air (in it's heat driven expanded form) would not compress as well and leave the power stroke stage of the engine hindered and raise engine temps as well (further repeating the cycle of heat air, draw in air, get hotter, heat air, bring in air, get hotter, etc.). If this cycle continued you would see engine life-threatening heat. Not enough for an overheating (as I'm sure many forum members can drive witht his setup without drastic overheating) but enough to lose a considerable ammount of power. Now I have no way to actually prove what I have stated but I used simple knowelege in physics. I can probably be proven wrong but my biggest backup would be this. If this "air bath" is so effective or if the gains outweigh the losses then why didn't mazda put a scoop on every hood they made? or any manufacterer for that matter? Surely the people with heavy wallets and extensive educations over at BMW, Mercedes Benz, Bentley, Ferrari, etc. would put a forward facing scoop on all their cars turbo or not. If your counter example to that is styling, then why not race cars? Put a scoop over every engine in a race car if it helps, but why isn't it done? The scoops you see on Vette Z06s, Camero Z28s, Trans Ams, Vipers, and such are all directly routed to the intake. Pumping col air into an engine bay simply isn't going to ammount for much if anything. It seems good in thought but upon further review the downsides are clear.

raptor22

You are forgetting one thing; the air travelling under the car in the FC produces a low pressure area right behind the engine bay that draws air out of it, so high pressure reducing airflow through the radiator isn't as much of a concern.

Why don't high end cars use hood scoops? The anser is that there are several more effective ways to push air into the an intake than a hood scoop. The hood isn't particularly high presure, and if you place the intake in a different spot you increase airflow more for a given intake area than you would with a hood scoop.

Like I said before, since thehood isn't in a very high pressure spot as it is, I doubt that it really does a whole lot of anything.

BoostedRex

BlackS5, I can appreciate what you are doing. As long as you do take care in stripping weight off of your car then you can reverse that process if/when you feel like it. And yeah, lexan rear hatch and windows would surely shed some weight off of your car. Also, a nice fiberglass or CF hood will also help to shed some weight off of the front end.

Now here is my take on the hood issue. Granted I'm bias towards the 5one5 Innovations vented hood, but my argument is a solid one. A TII hood will over pressurize your engine bay and will seriously hinder your cooling systems abilities. It doesn't matter what other benefit you might gain here, it's not worth it. Our engines run hot enough as it is and hindering the cooling system at all is a bad idea. Now a vented hood like the one from 5one5 will help with engine bay temps and will also improve the efficiency of the cooling system. There will be a low pressure area created over the vents in that hood. That low pressure area will naturally draw more air out of the vents to try and neutralize the pressure differential, thus drawing more fresh air in through the nose of the car and more hot air out of the engine bay. And what is directly in between the nose of the car and the engine bay? The radiator! So you'll see increased airflow through the radiator while at speed. And last but not least, the 5one5 hood is made out of fiberglass so it will be significantly lighter than a stock TII hood.

While I am also a purist when it comes to the '90 GTUs model, this isn't my car. So I do wish you the best of luck in turning your GTUs into the car that you truly want. And I hope that everyone else will let you be a big boy and make up your own mind as well. If there is anything I can do to help then just let me know. And if you are interested in any of the parts from 5one5 just let me know. Good luck bro and I'll be looking forward to meeting you at one of the NorCal events.

Zach

383Mazda

BlackS5... What's the waight difference in the rear window swap? I'd like to do that to mine also. And about the hood, do what you want! I really doubt you'd see ANY differnce in any of your guages as far as water temp goes if you had a hood scoop or not, and if you stuck a "boost guage" under your hood, you wouldn't see a difference in there either. If it really did raise engine bay temps enough to warm up the rediator, your thermostat would just open sooner, that's all That's also why they design radiator fans and shrouds, you could drive with your hood off and you're not going to see a major difference! They make it seem like you'll run 500º with a hood scoop!
And if people keep complaining about "ricing up" your rx7 (which was made in japan, isn't it???) Just stick a V8 in there, it's the opposite of "rice," it shoudl keep them happy right?
Good luck with YOUR car.