"You are not authorised to download this attachment."

 

Sorry- pic originally posted on another forum- need signon. If I were at home I could upload, but I can't save any pics to the work compy

 

https://www.rx7club.com/attachment.p...9&d=1197344303
How about now? I knew I posted it on this forum at SOME point

 

alright regarding this carbon fiber intake. from what i know about carbon fiber, fuel makes the resin soggy. correct me if I'm wrong but wouldn't I not be able to run meth injection after an intake setup like that?

 

If you are that set on it, then I'm all behind someone who actually plans to follow through with something, but how much do you think it's going to cost to replicate S5 VDI, UIM, and LIM in carbon fiber? Hint: a LOT. Like, for just your set, I bet it'll be near the cost of a good rebuild, just because you can't just pour CF into a mold like steel/aluminum and have your part pop out. :/ I mean...you can mold it, but...you know what I mean.

 

I just want to throw a couple things out there that haven't been addressed that may or may not have been considered.

1. I'm not sure about the fc's but I know the fd's (my friend has one) intake gets super ******* hot. Like really hot, I don't know how this will affect/warp the intake.

2. How thick will the carbon be? Just one layer? I know with the plastic intake on my e30 (I know its not an rx7 ok ok...) but I can see that the intake gets sucked in when I'm WOT...

3. Really necessay to make a carbon intake of the same shape? Making your custom intake with justification (in my eyes) would be to improve the flow of the intake, but as you just stated its already pretty good...

You should just turn up the boost

PS: I've done a little carbon work, and its not very easy.

 

^ This project is not about efficiency or productivity, it's about being different, and as long as the OP achieves that it will be a success.

 

still researching on how other companies make their cf intakes, and which resins they use. i already thought about the fuel reacting with the resin and the problems it could cause. and still thinking about what to do about that. thickness and layers, between 2-3. i'm aware that it gets hot. and if worse came to worse, i could just make the plemun out of cf, and not the vdi manifold, but i am hoping to make the vdi manifold out of cf as well.

the only thing to think about is the runner length, and if anything, i'd shorten it an inch or two, or connect the first runners into the horseshoe runner a little closer to the engine.

as for the supercharger you've got on your car, is that the paxton-neilson one, or the newer one straight from paxton? how's it run? think you can get a few more pics? think it'd fit right where the air pump goes instead of above where the air pump goes?

 

That is a Paxton/Nelson unit, which is just an SN89 paxton blower with a kit to bolt it up to a 13b motor. This one was rebuilt and upgraded to an SN2000HO (high output) and is good for 10psi, which is actually limited by the pulley size (the original 3.25'' pulley will overspin the blower above 5k rpms) to ~8psi at redline. I also have a B&M trans cooler and a Tilton pump sending royal purple trans fluid out to the rad area to be cooled and back. It is not the NOVA blower, which is what is in my avatar.

As far as the stock air pump location, the blower's housing is way too large to fit- and as far as I know, the NOVI blowers are pretty similar in size.

The car runs and idles like stock, although it does feel a bit anemic off the light if you stay below 3k rpms. When you get between 3-5k, you can feel the car start to come alive. Where this setup shines is at highway speeds- I just LOVE being able to romp on it and break away from the pack if necessary. The blower whine is noticable enough even at idle to make people wonder what's going on under the hood, and above 5k rpms it sounds like you're gonna suck the glove box into the motor Stab the throttle at a light, and it sounds like a beast.
S/C's are not for everyone- I got this one used, with all receipts and docs for cheap, and I had to go for it. It was really a learning experience getting it all dialed in- I did all the work myself- but unless you are a relentless tinkerer and like to take the time to get it right (which given this thread I'm gonna guess you are) it isn't really the easiest way to get there. I did quite a bit of fabbing, even though the "kit" was for a 13b motor. It needed a lot of tweaking, but for me it was worth it. Plus I just can't keep the grin off my face when I hear that blower whine

 

As for pics, I could snap some tomorrow and post em up. Let me know if there is anything you'd like to see in particular.

Also, user *touch* has just about the same setup as me (although he has since popped his motor) and could give you some insight as well.

 

You can have the stock turbo rebuilt. Or, pick something better like the GT30.

Pick up a GT30 with a T3 1.06 turbine housing and an internal wastegate for $1400:
http://www.atpturbo.com/Merchant2/me...egory_Code=GRT

Make a very simple manifold due to the internal wastegate.

You'll still need a standalone which you are planning to get anyway with the supercharger.

Pick up a generic bar and plate intercooler (eBay, $100) and fab up the plumbing.

Why would you need a fuel cut switch?

This setup will put 300HP to the ground with about the same torque and make boost instantly. Won't hold boost to the end of redline though.

Sounds like it feels like a laggy turbo setup.

Ah, but yours is used so saying it cost $1500 isn't really fair when comparing to someone intending to buy everything new.

 

pics, front and back views without the fan shroud in the way, if possible.

and thanks a lot tom. if all goes right, i'll be in florida, according to your pic on the right, your in fl... i'm moving to hillsboro, just a few minutes south of boca. maybe one day we can meet up and compare supercharger set ups.

i was planning on picking up the blower straight from paxton, it's the one commonly used on mustangs, and fabbing it to fit on the 7. it sounds cool from what you said, but what were the tweaking and fabbing mods you had to do? paxton, when i talked to them on the phone, said that i just had to measure my crank pulley and the distance to the blower, and they could give me the specs for the pulley i'd need.

as for the way you set up the oil lines, did you have to drill into the blowers oil resivor? the blower i was looking at has a self contained oil resivor, or i could use cycling engine oil, if i tell them to set it up that way. i was considering going with the self contained set up, and just changing it's oil when i change the car's regular oil. the blower they said has a drain hose and a valve, which sounds easy enough.

i can mount it where you have it, but i was kind of bent on making it fit where the air pump goes, but i guess i'll have to get the blower in my hands before i can realize that thought.

we'll see

as for the turbo talk from araon...

i never fully wrote off adding a the snail to my car, it's jsut that the blower sounds more interesting. tell you what. if i dont like it, i'll later trade it for the turbo set up, k?

 

do you have any idea at what rpm the blower will start to get damaged? that's one question i forgot to ask the paxton tech people when i called them. is there a range with which it works, like does it have a 5K working range, which can be set according to the pulley it has? i've got the s5 na, so i've got from 0-8K rpms to play with.

i'm thinking of getting a pulley that doesnt do much for the first 2500-3000 rpms, and hopefully having it work till redline. safely for itself.

the newer blowers are for newer cars, which now a days are comming with more and more higher redlines, so i'm guessing that they'd be ok for that

as for the turbos.. what about when they kick in? do they max out like a blower will?

how long till they spool up from a cruising speed until you feel it?

at crusing speed with the blower, is it instantious, as i've been told?

 

if you tune your setup, a turbo can kick in really early, like ~1500rpm early (as aaron said). you've got to stop assuming that turbos have lag. only turbos that aren't properly tuned have lag.

 

i understand that. perhaps i've just heard the term turbo lag wayy too many times. are there really that many people who are running them who then dont know how to tune them?

so how exactally do you tune a turbo, if you dont mind my asking.

 

I suppose you are right about that- I got a killer deal, and did the work myself. As for laggy, I wouldn't say that- when you are above 3k and nail it, it feels pretty instant

 

Yes, see above post. As for the pulley, I am running a 3.75" pulley. It keeps me in boost until redline. But my s4's redline is lower, and the blower is not a stock SN89.

 

cool. good to hear that you can red line it though. i'll only need 1K more than you out of my blower and i'd be happy

 

playing around with the intake plenum length and width, you'll be able to move the torque curve up and down the rpm range as well as mess around with where you want more area under your power curve, below the peak or after.

At least tuning motorcycle engines that are n/a custom intake runners as well as plenum sizes and what not...

As for original part of it, I think this is awesome, I'm sure you're learning a lot and it'll look bad ***

can someone point me towards how the vdi works?
I think fuel + resin is ok....but don't quote me haha

 

the vdi is the variable cynamic intake effect. it looks complicated at first, but if you read enough about it, then stare at the diariagram for a few hours in the factory service manual, you'll begin to understand it.

it's kind of like the 6 port actuater valves, in that at a certian rpm, it opens. the vdi opens at 5800 rpm i think, and under load, to allow the pressure wave that is created when the rotor passes/closes the intake port to be sent to the opposite rotor, which is accepting it's own intake charge at that moment.

i can understand the theroy to some degree, and after reading enough about the system to give myself an annuresium, i'll just say that vdi = good.

changing the runner lengths in which the air travels through or the angle at which the air is aimed through the intake might help, but the vdi should stay in the system.


now what i'm still wondering though, is how will having forced induction effect this pressure wave.

will having a supercharger even allow the pressure wave to back track through the vdi, as the pressure from the blower will be constantly pussing its way towards the combustion chamber.

turbos dont have a vdi valve, so i'm wondering how having boost and a vdi will effect things

 

So does my GT35, and it'll put down over 400whp

3,000rpm + if you mash the pedal it just moves. I can build 15 psi by 4K if I tromped it at 3K.



Just for "lag" reference

 

Most of them don't handle much past 75,000 RPM. I'm not a supercharger expert by any means, so checking the datasheet from the manufacturer is probably the best bet.

See, that's crazy talk to me. You've just created a laggy setup under the guise of worrying about lag.

The thing is, at what point do they start making boost and do they hold it until redline? Also, the size of the blower VS. the size of the engine is important. The rotary flows air like no other. I see turbo V8s all the time with turbos so small they would choke a stock port 13B, yet the V8s seem to make power.

Depends on the turbo really. As mentioned, the stock turbo is like an on/off switch. Small aftermarket turbos act the same way. Plop a T70 on a stock port engine and don't expect full boost until 5K. Use a GT35R on the same engine and have plenty of boost before 3000 RPM. Go a bit smaller and have boost whenever you want it with some sacrifice up top. Smaller turbos will run out of flow just like a smaller supercharger will. Paradoxically, if you want to run a smaller turbo it's often advantageous to run a larger hot side (why I would say to run a 1.06 on a GT30 while maybe one size down on a GT35 is best).

The key with a turbo is that if sized properly, you can choose your boost at any point.


Depends...A small turbo will be right there. In my old 6 port turbo setup (using the HT-18) it would make full boost at any RPM under moderate throttle.

One would assume, if it's geared correctly.

I always find the term "turbo lag" to be odd. There are certainly laggy setups, and back in the day I'm sure there were a lot of crappy OEM setups. The TII has never been laggy. Drive any OEM turbo car today and I doubt you'll be able to detect any lag.

I'm willing to bet this whole "turbo lag" thing started from poor OEM setups, or the aftermarket people who thought that bolting any old turbo onto any old engine was a good idea.

Tuning too is a big part of it.

So many RX-7s I see are tuned far too rich in the low boost area. This is a critical part of the map where the turbo is trying to gain RPM but the sluggish engine and exhaust gasses is resisting due to running 10:1 A/F ratios. This area is easy to miss as many people just make a few dyno runs and call the car "tuned". Even on the street, just a few roll ons at 2000 RPM in 5th gear will make it easy to clean up those areas. Going from the typical 10:1 to high 11s is a MASSIVE difference. The turbo comes alive and that "lag" is gone. Just make sure to WATCH YOUR TIMING when doing this as it's easy to run too much advance as again, this is a section of the map often ignored.

Another thing is wastegate spring tension. That 10 PSI spring is starting to open at 6 PSI or so. An electronic boost controller will keep it closed until the turbo actually makes 10 PSI.

Mazda made the turbo manifolds very simple. It's less important to tune the intake manifold when you can just up the boost, and you can see how the 6 port manifold makes packaging a bit of a problem. Try fitting a top mounted intercooler...

Air flows into an engine because the chambers are under low pressure and the atmosphere is under high pressure. Same thing with forced induction, just the pressure difference is larger. Now at some point there is probably enough flow to break the VDI advantage but I don't know where that is. And at that point it will begin to act just like a regular intake manifold anyway.

 

you'd really rather see me do a turbo set up, would'nt you?

you should be a turbo salesman or something.

 

I would, because I've been around long enough to see all (well, most) the supercharger projects attempted and then fail.

I think you'll be happier with the end result if you go turbo. But if you want to supercharge, I just want to make sure it's done with a clear idea as to what's available on "the other side".

 

haha great stuff... you can always switch later too

Where'd you get that vdi stuff? I'd love to read into it as I'm looking to do the same for my formula team (or at least the research)...

I know the newer r6 motors have this variable intake runner lenths to adapt the intake to the rpm, but I'm not sure if the is the same thing. If so...Mazda was pretty smart in the 80's