SammyD

So I'm going to go with the basic 'intake, exhaust and tune'. Puresports in Ramona will do it. It'll be their stage 1 type of package - I don't want to go crazy with this thing.

Question is - what kind of performance #'s can I expect - like 0-60 and quarter mile? I think I'll get a 30 RWHP increase from these mods with a safe tune, right?

I was originally going to buy an Elise but decided to save myself 28k (20k for a '95 F3 with 36k miles v. 48k OTD for an Elise). I'd like to know that I have a car that can beat or is at least equal to the Elise.

OKRX-7

That should put you about on the right track for straight line performance with an Elise but the 1000lb handicap will be hard to overcome when it comes to the track.

The damned Elises are just to light.

SammyD

Elise weighs I think 1950lbs, 190 HP - so 10 HP/ lb

F3 with 35 HP gain at the crank - 2850lbs(?) 290 HP - 9.8 HP/ lb

So the Elise would be faster. Is that some fuzzy math or what?!

Funny thing is, I rented an Elise in Vegas and it didn't feel as fast as my stock F3. Wonder if those foookers detuned it for reliability.

saxyman990

First, what the heck is an "F3"?

Second:
No, that's what we call incorrect math.

If you're trying to see the Power/Weight ratio, then you need to start with Power, and divide the weight. For the numbers you were using :

Elise: 190/1950 = .097
FD: 290/2850 = .102

In this scenario, the FD would have a better Hp/lb ratio.

Of course, that number doesn't mean JACK CRAP, and does not indicate that the FD is a faster car, so this was basically an exercise in futility.

-Rob

Montego

iTrader: (1)

IMO to gain the most out of that set up: You should include a bigger IC while you are at it. The stock IC sucks donkey nutz.

Assuming non ported engine and stock twins at 10 psi:

With full exhaust, intake and a tune you should be 240 RWHP - 260 RWHP. Add an efficient IC you might reach 290 RWHP. The Stock IC quickly becomes a bottle neck when one is enhancing the performance of their vehicle.

Herblenny

iTrader: (13)

SammyD,

I'm guessing you are new to "FD"s??
I'm not sure what they are trying to do at the Puresports (are they rotary guys?) but I don't quite understand what you mean by 'TUNE'?

If you have PFC.. you don't need to get it 'tune'd for just intake and exhaust.. And when you say exhaust I'm guessing catback??

I would highly recommend you looking thru the FAQ section for FD's

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/

Good luck but I wouldn't waste a dime tuning your pfc for just intakes and catback..

SammyD

Never was very good at math!

I got my terms mixed up. Still not grasping what your numbers mean - I've never seen numbers like that cited in power:weight listings. Anyway, I'm going off off a Z06 ad that came out of MotorTrend or the like:

Power to Weight (lbs. per hp)

Corvette Z06 - 6.2

Ford GT - 6.3

etc.

So what I figured out was that an Elise would have 10lbs per hp, an FD (sorry) 9.8, so you are right, the FD would have a better ratio!

Thanks for being a willing participant in my 'excercise in futility'!

SammyD

Yes, one week new!

I've read the FAQ's to death and read that even a new downpipe can increase boost and result in a potentially lean condition. I'm not willing to take that kind of $6k gamble. A new exhaust will apparently uncork the engine pretty substantially, so I'm guessing a tune is necessary to increase the rate of fuel delivery to make up for it. When I say 'tune' I mean chip or whatever it is you have to do to reprogram these cars. And yes, just a catback.

How about some quick advice on intakes - i see all these cone filters and they look like they're just gonna suck hot air out of the engine bay. Do intakes really make a difference?

Montego

iTrader: (1)

For now forget the "chip/ tune"

1) get a boost gauge.

You can perform as much mods a you like as long as you stay at 10 psi. and I mean no spikes nothing.


True cold air intakes do work. See Adamc's cheap bastard intake, M2 intake, Rotary extreme intake so you can see what they look like.

Like I said earlier your biggest bottle neck is the IC. You can have the COLDEST intake in the world and have it's effects be worthless by a heatsoaked IC. But you can have the worst intake and yet have it's bad effects become negligle with a good IC.

Obviously the best combo is efficient IC with an efficient intake.

On a STOCK computer I'm running:

Street ported engine
CAI
PFS SMIC
DP
MP
Boost is set at 10 psi
Stock catback.


What I really need is a PFC and catback so I can get the most out of my set up. Reliability wise the car is fine

SammyD

I seem to have a fundamental misunderstanding about tuning. I thought that the mods were designed to increase boost, yet you have yours set a stock levels? So 10 psi of cold air generates more power than 10 psi of hot air? Gaaa! I guess this makes sense. Thanks.

Montego

iTrader: (1)

Most mods are done to increase efficiency not boost. A more effient set up = more power no matter what boost level you are at. The increase of boost due to mods is a side effect and has to be controlled and set to a level were you are able to support it. Whether that be 10 psi or 20 psi.

DGblk93

SammyD-

My buddy at work just got an Elise a month ago. I drove it. Fun car - but the FD is MUCH more comfortable. My butt dyno also tells me that my RX-7 feels a little faster in stock trim. It's the turbo effect. That little Elise doesn't have a lot of torque and is only really fun above 5,000 rpm whereas the FD spools up pretty quicky and doesn't give up till 8K. With a few bolt-on mods your Mazda will be faster IMO. I have no data to back this up - just my experience with driving both cars.

adam c

iTrader: (2)

Boost is measured as a level of pressure (psi). In order to have pressure, there must be resistance to the pressure. As you remove resistance, you must increase CFM to maintain the same pressure.

In an FD, we modify the car to remove resistance. That means increasing CFM to maintain 10 psi. That is why a modified FD at 10 psi is faster than stock. It is running much higher CFM at the same pressure.

Hope this helps

Herblenny

iTrader: (13)

This is what I tell to most newbs on the forum.. Don't get a chipped ECU. I've had it and most veterans on the forum have had either pettit or M2 some point of owning their FD. My M2 never fixed my issue with 3k hesitation and it wasn't until I went PFC. M2 stage 3 ran quite rich and I personally didn't think it was that good. 8bit vs. 16bit... maybe might be the cause.. When I installed my PFC for the first time, car ran amazingly smoother (just base map). When I added HKS twin on top of my PFC, ran even smoother. So, get a PFC! PFC will also tell you most of the vital signs of the car.

I'm also assuming you have a dp already?

If you care about your investment.. there are ton of thread about the list of reliability mods for the FD.. Get those things done instead... I'm sure its in the FAQ thread.. If not, tell the mods of this section

SammyD

That makes a LOT of sense! Thanks!

Thanks Herblenny too. You know, I really didn't want to get into the car so far as hooking up boost controllers etc. Maybe I will down the road, but I personally consider the car a 'find' being a '95 with 36k miles. Mabye I'll just do reliablity mods for now and boost the performance a little further down the road. Thanks all!

dgeesaman

iTrader: (7)

A new downpipe is unlikely to increase boost much, even with a cat-back too. It's when you change all 3 exhaust sections to straight-thru (or downpipe, high-flow cat, and cat-back) that the increase in flow will overrun the stock wastegate. This used to be called the 3 mod rule, as in 3 flow-enhancing mods (such as intake, downpipe, high-flow cat/midpipe, cat-back, intercooler) is the limit of the stock ECU tuning. But the more current guideline is 10psi rule - keep the boost at 10psi, and the increase in flow is generally not enough to eat up the margin in the stock ECU tuning.

If you're worried about popping the motor, it's simple enough to just buy a cheap wideband and use that to follow AFRs, or install a PFC and have a good tuner put some time in with it. A well-tuned PFC will generally drive better than the stock ECU - more power, no hesitations, etc.

Dave

FLA94FD

No way! Adding IC at about $1000 even with tuning isn't going to add 30 HP at those levels, maybe after running hard track for awhile. Hold off on the IC until you really need it at stock boost levels unless you're tracking the car its not going to give you much at all. A good intake, downpipe hi-flow cat and catback with a good tune will get you to 280-300. That assuming you have a strong engine to start with, which is not a given these days.

With a good launch you should be able to get low 13's. The Rx-7 will be harder to get a great launch with. Lots of revs with a little slipping...

Montego

iTrader: (1)

AT 10 Psi

Are you talking WHP Or FHP? because I'm talking Wheel HP. 280 RWHP with just an intake and exhaust seems highly unlikely (50 Horses from stock WHP). But I would love to be proved wrong. Do you have any data to back up your claim?


http://dyno.zeroglabs.com/graph.php?...1&SUBMIT=GRAPH

as you can see 290 RWHP with an CAI, Upgraded IC, full exhaust, and a tune is not out of this world.

Edit:

You lost me here chief,

Who is talking about 1/4 mile times? and what does that have to do with this thread?

M104-AMG

iTrader: (8)

Don't forget there will be a Hazmat fee of about $20 or more depending on the SIZE of the Halon fire extinguisher.

I get mine inexpensively from the local fire extinguisher supplier that supplies my work (or your school, businesses, etc.) and in a re-conditioned bottle, not brand spanking new.

:-) neil

FLA94FD

SammyD is talking about 1/4 times, thats what he was asking. 60' and 0-60 are all over the place with the FD 1/4 mile time settle down a little. Stock low 14's - high 13's His mods should get him the low 13's with a great launch.

That would be a yes to rwhp. There is one assumption that with out a boost controler the boost will be higher than 10 so around 12.

Those dyno plots don't show enough information for one thing the second motor is ported. A port job could help or hurt the numbers depending on how its done. My point is that IC makes very little difference at those power levels even with tuning. Now if we were talking about going from 320-340+ yes, but with the stock twins at near stock level it just not going to add that much for $1000. When upgraded my IC I didn't notice a change at all, I think I would have noticed 30 rwhp. After I get my car dyno tuned I'm expecting 340rwhp+ with my stock ported motor at around 14lbs of boost.