rx7learner

I've been doing a bunch of reading and wanted some guidance. I think I'm leaning towards nitrous. I have a stock port 12a with all stock internals about 80k miles. From what I understand if I go turbo with my engine I have to run minimal boost to avoid hurting my engine. The thing is... my car is a daily driver. With a turbo I would be subjecting my engine to the turbo all of the time. Plus if I'm lucky... it seems I can get away with a blowthrough setup for about 1k (I have a mikuni side draft already).

If I only want the extra hp when I'm racing once in a while... it seems that a 50 shot of nitrous activated on demand seems more appropriate. I'm new to both options... but from what I read either option would require retarded timing, a richer mixture, and higher octane gas to avoid detonation.

So.. considering my situation (activation on demand with a limited budget) I'm leaning more towards the nitrous. I read the DIY nitrous kit site from the UK which inspired me to look on ebay for a used kit... from what I'm seeing I need

2 foggers jetted at 25 each to push 50hp total,
2 solenoids (1 fuel & 1 nitrous)
1 distribution block to break the output from the solenoids to the 2 foggers
2 lines from the solenoids to the distribution block (1 nitrous 1 fuel)
4 lines from distribution block to the foggers (2 nitrous 2 fuel to each fogger)
1 long line from the bottle (with guage and valve) to the nitrous solenoid
1 T fitting for my fuel line fitted before my fpr (fed by my holley red)
1 fuel line from the T fitting to the fuel solenoid
1 toggle switch to power the throttle switch
1 throttle switch to activate the solenoids at WOT

What I listed may be incorrect please correct whats wrong... but if I am on point I think I could piece that together on ebay for about 250$ instead of the minimal 1k on the turbo. The difference in cost is a whole lot of nitrous refills. I also dont know if it makes a difference what components you buy... are all solenoids, bottles, foggers, distribution blocks created equal? Is the only variable the shot jetting for the fogger? If so... I think I could probably get the whole setup less than 200$.

I know that there are people out there pro and against nitrous but the way I think of it as one thread explained. Forced air is forced air... Any guidance appreciated. Thanks again.....

steve84GS TII

For the most part,turbos are only a burden on your engine so far as you right foot makes them a burden.
I can drive all day long,in a normal fashion and never once boost.....and my car rewards me with 20+MPG.

There is nothing wrong with nitrous,it has some great advantages like internal intercooling and simplistic plumbing/installation.Its also no more abusive to the engine than other forms of forced induction.Most people screw it up because they run a cheap dry setup that leans to engine into destruction (think blowtorch)....or they get into the nitrous too low in the RPMs and detonation does the engine in.
Also,in addition to the re-fill penalties,with nitrous you have to consider the legal and safety ramifications.......Vs turbo/supercharging which it totally safe and legal everywhere.

rx7learner

ok... Is nitrous illegal for a daily driver in fl? no emissions here (yet)?

did my parts list look correct?

is there a difference in parts other than the jetting for the foggers? (i.e. 1 solenoid that will work versus another that wont????) or are all solenoids created equal?

steve84GS TII

Dont quote me,but far as I know, nitrous that is hooked up and plumbed is illegal anywhere, on any street vehicle.
It has nothing to do with the smog or effects to your engine.It has to do with DOT regulations regarding high pressure vessels and moving vehicles.The nitrous bottle is a BOMB.....and having it hooked up, means that its protective transport cap has been removed.In addition to killing you with the blast and shrapnel,the nitrous itself as an oxidizer, can accelerate any existing fire that might be present when/if it explodes after a bad wreck.
Of course,its only illegal if you get caught.

I personally dont mess with nitrous,not that I have anything against it.Someone with personal experience would better be able to guide you with component choices.
When it comes to rotary power-making, N/A porting and turbos are the norm,followed by superchargers,then nitrous....so theres less expertise to glean from others,regarding its use and setup on an RX-7.

rx7learner

I tried google'ing whether it was illegal or not and had no luck. I would rather not mess with it if it's illegal to have it on a street vehicle. If anyone can confirm I would appreciate it.

Morey987

Not sure if it's illegal to have,,,, or just illegal to USE. Kind've like those neon underglow lights. You can HAVE them on your car, but the second you use them while you are driving down the road they'll bust you.

rx7learner

If that's the case how would they tell that you used it? I'm going to take a trip down to my local speed shop and ask them.

steve84GS TII

Thats probably the jist of it.
Its not illegal to boost power to your engine......but it is illegal to have a high pressure canister open/un-capped inside a moving vehicle.Again,its not a smog thing,its about violating D.O.T. rules for transportation of hazardous products.In order for you to USE the nitrous,you have to take the cap off and screw on the hose that goes to the engine.

Just like gun laws.
Its not illegal to have a rifle slung in your back window........but if its loaded,your busted.

MontanaKid

do both

FC_Fan21

Turbos are only bad on your engine if they are not tuned right. Thats why cars come stock with them. Nitrous on the other hand is putting somthing in to your engine that the engine is not used to being there. It is normaly very harmful to use on a stock engine, but in very small amounts could not be too harmful. Just about as much as dumping the clutch and roasting the rubber.

Morey987

I had a great deal of luck with a 50 wet shot on my stock 12A And if you're going for a bare bones price range. You can't beat the price of an ebay nitrous system! You can pick up everything you NEED for like 300. Some of the frills will cost you a bit more, but it's definitely the cheapest power adder, especially opposed to a $600 carb, $600 turbo, $200 manifold, $30 in oil lines, $100 in exhaust. And it can get even higher than that!

steve84GS TII

Oxygen and fuel are supposed to go into the engine.No car comes with nitrous because refilling tanks is hardly convenient, and there are the aforementioned safety reasons.
Turbo/superchargers and nitrous do exactly the same thing,push more oxygen into the engine.The means with which its administered (mechanical or chemical) makes no difference to the engine.If either delivery system is not tuned right with the proper fuel delivery increase,then either will destroy the engine in the same fashion.....lean-out detonation.

Morey,you hit it right.
It is cheap and easy power,and a W-E-T system is the only way to go for easier tuning.Why some people cheap out and slap a dry system on,thinking thats all there is too it,is beyond me.I guess they are the same breed as people who think a turbo just bolts to the exhaust manifold and its ready to run........

rx7learner

Man... I havent checked back and this thread grew... I think I might be swaying more towards the turbo now. Not only for the non-consumable aspect of it, but the challenge of getting it done, the uniqueness of a turbo'd 1st gen, and from what ive seen on the "bad 83" you-tube video... it looks like some serious fun.

Anyhow I started looking at the single turbo forum to learn somethings and all I can say is... it is awesome. Ive read about 6 hours this weekend and best of all another member who has been through it has been walking me through everything I need so that I can get a good idea of what the challenges will be. He's even hooking me up with some parts once I descide to go Turbo.

It looks like it's going to end up running in the range of 1500$ so about 1200$ more than the wet kit. I already have a Mikuni 44.

I'm looking at...

HKS turbo manifold redrilled and ported to fit the 12A
Upgrade my fp from a Holley Red to a Holley Blue (I have a good FPR & FPG)
HKS 40mm wastegate
Blow off Valve
Carb Hat for my Mikuni
Intercooler (24 x 12)
Intercooler tubing
MasterPower T04b turbo
Boost Controller
Fabbed downpipe from my local exhaust shop.
Time

I still havent reached a comfort zone with my knowledge of going turbo yet because it is difficult to find a single "road map" for someone with a carbed 12a but I'm getting there. I greatly appreciate the help I'm getting from boriqua51371 it almost seems like he's breaking a code of silence but he's been a blessing.

On our forums there is a wealth of knowledge but its bits and pieces unless I'm missing the holy grail somewhere. 1st thing I vow (provided I go Turbo) is to get a cut and dry "how to turbo a carbed 12a". It's intimidating when you see many posts that talk about incomplete turbo 12A projects. I just dont want to start buying parts to find out I'm in above my head.

If any of you turbo guys see some red flags or missing required parts I would appreciate any tips (other than rebuilding and porting my stock 12a which I know will be next in line).

Thanks.

Morey987

I think a lot of the problem with the 12a turbo is that people get over their head financially with the system. It is not a cheap ebay run of the mil system from what I have read. Turboing a carb seems like it's a lot of tuning and jetting. So it isn't for the average backyard mechanic. I'd go with nitrous for a little bit until you were SURE you got the cash to do it. I completely agree that a turbo first gen is something special and I plan on doing it as well, but the nice part about nitrous is, there is a vast market to sell it to when you decide you don't want it any more. You can just sell the kit to the next guy! If you get a used one then you can pretty much break even! Just don't over do it! Horse power wise I am guessing you can reach the same numbers as a 12a with an intercooler.

kgray

You will need a boost referenced FPR if the one you have isnt. Then you will have to deal with the oil system.

rx7learner

Thanks guys. I have a message into Robert at rotary shack asking about the carb hat and any other considerations I need for boost preping the mikuni. I just did a fresh master rebuild on it.

The oil system (I'm assuming you mean the oil to the turbo.) From what I have read there is a way to run the line from the area next to the OMP.

I do not have a boost referenced fpr (do not know exactly what that means). I just have a holley fpr. Need to look into it... thanks....

Not concerned about re-couping price if I decide to sell afterwards. There was a 12a draw through setup that looked spray painted and abused that went for 500$ on ebay. I've seen other "better looking" 12a turbo "sets" go for around the 1k range on ebay. I think people like the simplicity of what they think is a bolt on set.

On the Nitrous option I was wondering... if you are running nitrous shots for lets say 50hp with a 10lb bottle how long would that take to use? and how much does it cost to refill the 10lb bottle?

Morey987

I think I was paying $35 to refill a couple years ago. Depends how trigger happy you are. But if you use it once in a while. You can easily get a month out of it. Just depends how often you NEED it. I used it quite a bit and still got a month out of it. I know guys that use it sparingly and easily get a couple months out of a 10lb bottle

rx7learner

Too Late already started my 12a turbo project. Got a used 87-88 turbo and manifold with bov for 125$ on ebay. Now the flood gates have opened.

http://cgi.ebay.com/ebaymotors/ws/eB...m=230170037767

Couldnt find one for crap in FL... only 6 people looked at this before I did a buy it now (email notification to my blackberry when it listed). None the less its a chance I've taken...

There's a boatload of info threads on next steps. ie plumbing the oil lines, drilling out the holes in the manifold and adding the rb spacers to clear the intake, mounting a volvo ic, getting the downpipe done... getting the ic pipes done... using a boost reference fpr... and so on... and so on...

I'm a mainframe software engineer so I love to get my hands dirty a bit instead of on the keyboard. Time to pull the 94 Q45 out of the garage and let the fun begin. I'm sure the saga will continue. Any tips please let em roll... otherwise I'm sure stuff has been covered in another thread I'll be reading tonight.

OOOH and BTW I learned the mikuni does not need to be boost preped (floats are solid) just needs to be jetted appropriately (another one of my research points)

Jeezus

iTrader: (4)

You also have to seal any parts of the carburetor that can leak air, because anywhere it can leak, is anywhere the boost will go.

rx7learner

Thanks Jeezus. I just did a fresh master rebuild using a woolfcreek kit and I have my carb hat in the works. Is there anything that needs to be sealed other than that?

81WideMariah

iTrader: (8)

yes... ANY port, that means the vacum port on the top of the carb, the OMP ports underneath the carb, probably want to seal the throtle shafts too somehow, it's gotta be sealed or no boost. You also need a rising rate FPR this will have a spot to hook up a vacum line to it and will increase fuel pressure as boost increases usually at a 1:1 ratio.

rx7learner

Thanks guys.... I was just comming back to post that I forgot about the OMP inlets and you beat me to it 81WideMariah. I'm running premix now so if I get rubber caps and use worm clamps would that seal the OMP inlets sufficiently... or maybe I can plug them with a threaded bolt of correct size?

I know this has to be in other forums but while I have the elders attentions I will ask....

I havent seen any posts on sealing the throttle shafts... but then again I havent seen any posts on boost prepping a mikuni except one that said it does not require any... but apparently that is an incorrect statement.

rx7learner

You talk about discouraging. Now I hear from a reliable source that

"that choke on the Mikuni will not hold boost and you will have issues under boost with the float bowl venting pressurized air"

It's really becoming very hard to distinguish what posts to trust.

also...

"Make or buy a 12a manifold, dont try and adapt a stocker"

and

"A little end play" probably means that you just bought a paper weight"

according to this info I'm back at ground zero (even in th hole some because I thought I had a carb that was already boost preped).... Nitrous is looking better and better. I may have learned a 150$ lesson.

steve84GS TII

Play in turbos is normal in the "up-down" directions since there is no oil wedge supporting the shaft.What you dont want is "in-out" play on the shaft.Looking into the hotside will also give you a clue as to if the oil seals are shot.It should be dry and brown in there,no wet gooey black stuff.

There really is no such thing as a carb that requires no prep for turbocharging.
Carbs work off of atmospheric pressure, and lack thereof in the intake path of the engine(vacuum=pressure below atmospheric).
When you boost the intake manifold pressure from below, to above atmospheric,there are going to be all kinds of problems since outside atmospheric pressure is needed to push the fuel from the floatbowls,down through the jets,and into the venturies to be mixed with the low pressure air present in the carb body.The float chambers will have to be refferenced to the intake before the throttle,so that there is adequate pressure in the bowls,to move the fuel when boosting.When not boosting,the intake before the throttle is at/close to outside atmospheric pressure and the carb will behave normally.......it just cant be plumbed to the outside air,or youll have boost loss and little to no fuel delivery.Ram-air equipped bikes have the same issue when carbed,since several PSI of boost can be produced at speeds over 100MPH.

Yea,choke shafts have to be adressed just like throttle shafts.There must be clearance for movement to occur,but any play means that leaks can/will occur.......I love EFI.

81gsl12a

iTrader: (1)

or you can build a air tight box around the whole carb problem fixed

EFI = EZ way out
CARB = FTW and cheep

woot