Street Port MPG?
 

Im wanting to get a full port on my n/a. Was wondering if anyone has had this done and how it affected your gas mileage.

thanks

Go get a turbodiesel VW if you want fuel economy. RX7s won't see anything higher than 20 with porting. And that's pussyfotting it.

it will all depend on how it's tuned and how you drive it.

I've only placed 260 miles on my newly done streetport. Still have approx a quarter tank of gas left. Before the build I averaged 14mpg. I would get about 200miles being heavy on the gas and and about 250 being light. So this is a little change. As what has been said before you still won't get great fuel economy with a 7.

again, it really comes down to how you drive it. I currently have a BDC streetported motor, RB 3" exahust and HKS intake, and run around 23MPG on the highway.

oh, guess I should also state Im running the stock ECU, injectors also, but a Walbro 255 pump.

That wasnt a very constructive comment about the VW turbodiesel. Im aware 7's dont get great mileage but with this car being my daily driver I cant afford it being much lower than 17mpg on average. So basically is it going to get worse or better? I was thinking on one hand more hp needs more fuel on the other more flow means engine doesnt have to work as hard. I dunno.

With out a doubt, the best fuel economy will only come from a vehicle specific tune... don't know what you're doing in that department.

...as well, driving habbits will greatly influence fuel economy (i.e. keeping it below 2500RPM and no boost).

My Turbo II gets horrible fuel mileage, for a daily driver... so I have a Volvo 850 Turbo. My best reccomendation would be to look in to another vehicle as soon as possible; keeping the 7 for 'fun'.

Back to your original post, I can't imagine getting better fuel economy from altering the car with a performance-based port... but to be fair, I'm new enough to not be very confident with rotaries and porting (i.e. wich benefits each port job would yield).

Oh really? Cuz my aggressively streetported TII gets 26 mpg with a shitty tune on the highway. oh an i should state that i have a fairly unrestricted 3" exhaust, 720/1680 injectors and a 9lbs flywheel.

it really comes down to quality of the port and tuning. and an rx7 CAN get 30 mpg. shit my 12a first gen got me 32mpg with a leaky exhaust. dont let people stear you in the wrong direction.

its a street port . . . dont worry about gass!!! . . .lolz

Then you sir are one of the few exceptions to the rule. :icon_tup:

I'm with you on this one. I'm having a hard time believing 26MPG on a TII.

I think there's more than likely some error in his calculations or methods to reach factors.

... YOU'RE JUST DOING IT WRONG! :lol:

i get 20 mpg city driving.

You should also think about getting a wideband o2 sensor and some kind of fuel management device. That won't only help your mpg but a porting doesn't do what it's supposed to until you have control over your fuel ratio.

I spose you didn't ask for opinions but I wouldn't pay for a port on an N/A. So unless you are planning to diy, in which case thats fine, I would save for a T2 swap since that'll satisfy you more in the long run. (reading previous posts it seems you are at a rebuild point)

i measured 13.8mpg on my last tank.

street ported turbo with 720/880.

Bascially Im trying to get to the 200whp number. I saw dyno numbers from an 88 n/a with aggressive street port done at Banzai Racing and it hit 188 without fuel management. Im hoping with the same port and an afc neo i can get to at least 195whp.

Okay so Ive got responses ranging from 26 mpg to 13. If I average those numbers Id be very content. Do the turbos get better or worse mileage in general?

I hate to break your bubble, but your not going to get 195RWHP on a streetported N/A motor. bridgport probably, maybe even a half bridge. 7RWHP is alot to gain on an N/A, and I don't thing a AFC will cut it.

please prove me wrong, i'd love to see it ~not being sarcastic~

in theory, turbos should get better efficiency but ti's so damn hard to keep off boost, it's addicting!

https://www.rx7club.com/showthread.p...highlight=dyno

196whp with a modded, stock S4 intake manifold.

Say no to misinformation!

A "full" street port? As opposed to what other type of street port? :)

Any reasonable street port will have little effect on mileage. Depending on how it is ported (mainly on the exhaust side) it may get better mileage, may get worse. Though one thing to remember is that your driving style is likely different from the driving style I would use to measure mileage. If you are heavy on the throttle, mileage is going to be poor either way.

My bridgeported 2nd gen gets about 25 MPG on the highway. Now that's on a standalone and a good tune, but that's a feat also easily replicated on a stock RX-7 that is working properly. Don't give out advice unless you are sure about it, please. Spreading misinformation helps no one.

And if you want to split hairs, a VW turbo diesel gets poor economy as well. My other car is a Honda Insight.

Only if you know how to tune are these things useful. And most certainly, a good tune will help in the mileage. A little leaning out of the mid and top range on the typical NA RX-7 is a nice boost in mileage and power.

If the engine is in need of a rebuild, it's a perfectly reasonable thing to port it. Just don't go hog wild and make a set of huge useless ports when a bit of minor adjusting is going to give a better result.

Not everyone wants a TII swap, and there's something to be said about a nice fresh NA engine compared to a junk yard TII drivetrain.

[QUOTE=need-a-t2;8878711]I hate to break your bubble, but your not going to get 195RWHP on a streetported N/A motor. bridgport probably, maybe even a half bridge. 7RWHP is alot to gain on an N/A, and I don't thing a AFC will cut it.
please prove me wrong, i'd love to see it ~not being sarcastic~

Easily done on a half bridge with a proper manifold setup. But I agree, it's going to be difficult to get 200 wheel HP on an NA setup without radical modifications. Few achieve this.

200WHP would be nice, but I'll give you some advice, as a DynoJet certified operator; don't set your mind on the 200 number. Instead, mod the engine how you think will best suit your expectations and requirements (decent power and fuel economy). The Dyno is really a tool for tuning air/fuel ratio, and any numbers/bragging rights you get should just be a bonus. Along that train of thought, Dyno numbers can vary greatly from Dyno to Dyno, so only compare numbers with people who ran the same Dyno with similar conditions (temp, humidity, operator, etc...). You still can't be 100% with these things in mind. Operators can alter numbers, or cheat the numbers. There's a certain 'guideline' for an honest-tune, and making passes doing different things can better or worsen your results.

Food for thought

217miles per tank on a highway.... or there abouts..

13BT Extend port with stock turbo and computer

I am getting 14 city, 25 mpg Hwy on an 88 TII.
Set up is a hybrid engine.
Street port turbo center plate, Street port 6 port end plates, Street ported housings.
9.4 NA rotors
Hogged S5 Turbo intake, stock IC
TII ECU, stock 550cc injectors, Aeromotive AFPR @45 PSI
Hybrid S5 turbo, ported WG, 9 PSI
HKS FCD
AFR stays below 11.7 all the way to 7.5k RPM
Cruise AFR is 14.5-14.9
Stock DP (hollowed cat), Corksport 3" exhaust
256 RWHP

Point being you can get decent MPG's with modified engines.

what exactly is a "Street Port SCCA standards (off internet)" I'm still skeptical, but I've been wrong before.

You guys need to keep wishing you get over 30MPG. The rotary is not an efficient motor. You'd be so lucky to see 20. Just enjoy the car and beat on it. Don't worry about MPGs. :lol:

http://www.scca.com/documents/Club%2...Definition.pdf

Anyone know if stock N/A's meet this rule?