Mpressiv

whats up....im new to the forum and the wonderful world of rotary....i am selling my M3 for a RX-7. I was wondering how much power i can expect from intake, downpipe, exhaust. another thing how much is a safe amount of boost to run on the stock engine? i have also heard that the stock radiator is much to small. is it a necessity to upgrade the the radiator? i also heard about problems with all of the hoses. and last question is what kind of times will i be running with downpipe exhaust intake and a boost controller running a safe amount of boost. Thanks a lot any help is appreciated.

Mpressiv

anyone? please...thats rough guys any help is appreciated.

rx7speed811

with the dp, intake, and cb, you should be able to run higher 12 second times, depending on your launching skill and the condition of your engine and turbos.

it is highly recommended by most rx7 owners to upgrade the radiator for better cooling, i think the most popular drop in replacements are from fluidyne and koyo. changing the hoses out for silicone also helps your turbo system out a lot, considering the stock rubber hoses are most likely six to eight years old and the underhood temps are pretty high.

a lot of newer members ask similar questions as you asked and thats probably why you didnt get very many responses, but if you need any help with more specific problems once you get your '7, the members of this forum can be of great help. id recommend doing a forum search on the "reliability mods" and also check out rob robinettes site, as it is also an excellent resource for any common questions.

hope this helped.

rx7speed811

oh yeah, one more thing. you should be able to safely run up to a full bar of boost (14.7 psi) using the stock injectors, as long as you use a reputable fuel computer or upgraded ecu. the apexi power fc seems to be the most popular standalone system on this forum, due to its ease of installation and tuning. you would definitely need an upgraded ecu for faster fuel delivery if you plan on upgrading the exhaust flow with anything more than the catback and downpipe, or you would be running too lean. the rotary engine is very sensitive to that type of thing.

Mpressiv

thanks a lot for your reply. i was just lookin around the forum and i answered some of my own questions by looking at other posts. i would like to be into the mid 12s. i was thinking downpipe exhaust as soon as i got the car. what would i be running with just those mods? will i need to upgrade the ECU with those mods and if so how much will that cost me? i know on the supras people get the fuel cut defencer...will i need that also?i will have about $3000 to put into the car after i get it. but i think about $1000 will go to the maintainance and radiator and new silicone hoses. how would you recommend i spend the other 2 grand? i appreciate your help thanks a lot.

Jeff

CantGoStraight

Hi Jeff,
Welcome to the club.....General rule of thumb is two mods before you need to upgrade ECU. Would be your choice...For example downpipe=cat back, or downpipe=cold air intake, coldair intake=cat back.....so on and so forth...silicone hose upgrade is not a preformance mod but a reliability mod. First and formost get a boost gauge so you can trouble shoot the turbo's when needed.

airborne

hey congrats and good luck with the mods.
$2k after radiator hmm...i'm assuming the car has nothing done to it? then how about
Boost Gauge $100
Downpipe $200
Power FC $1400
Replace ast $100

With those four and the rad upgrade you shouldn't run into any problems. If you can stretch the budget add intake/catback.
But i think you'd want the ecu, if you're going to continue modding the car you will need one so better to knock it out now while you have the cash.
With my setup below you can see what i did. with a good clutch i'd hope the hp would be closer to 300 and with just practice i should be able to touch 12s in the 1/4. i hope.

have fun with it!

KZ1

I have the stock radiator and it works like a champ, cools the car very well, I have never experience any problems with it, if you are going to race the car or use a front-mount intercooler then I would consider an upgrade, but other than that save your cash. Everyoen also talks about the AST upgrade or removal, I think this is greatly due to rob robinettes site, I have heard very little of these things blowing, and have even heard of the aluminum ones blwoing, MY ADVICE don't worry about he AST until it pops. I reassured myself when I saw that 3 rotor with stock AST.

Anyway, just thought I woudl give my opinion. If I were you I woudl get eveything running right, ie boost patteren, chaneg fuel filtre, etc. slap on a downpipe and intake just to start, that should give you an extra psi of boost.

CantGoStraight

How can you say not to replace the AST ????? I can think of 5 people in the last month with stock tanks that let go. My car had the original tank with a JB weld patch job on it, I'm guessing the car ran hot when it went because I have a coolant o-ring failure now. I would replace it or eliminate it ..... I wouldn't wait for it to go..........just asking for a blown motor if you wait for it to happen.

airborne

I'd think for the relatively low cost of replacing/deleting the ast its worth it. Just because when they go they tend to take the engine with em...

Mpressiv

thanks for all the replys and input. first off....what the F*** is a AST? abbreviations are killing me. i would like to do downpipe, exhaust, intake, some sort of ecu upgrade, boost controller, boost gauge, . will i need anything else to be able to run those mods? any fuel upgrades? Im really not looking forward to spending 1400 on an ecu upgrade. that ***** crazy. is there a cheaper alternative if i am just looking to do the above mods? i read about the FMIC being good because you can push the limits more and do more mods without running into problems. but if i am looking for the basic bolt ons will i need all that extra stuff on the FMIC as opposed to a different less expensive thing. i know modding cars isnt cheap as i found out with my last 2 cars (acura integra GS-R, BMW M3) but i am looking to get the most out of my money. maybe pettit ecu upgrade i saw someone else running on the site....any opinions? i work at an autobody shop so i once the paychecks keep comming in and christmas rolls around i will have more money to do the body of the car. once i get into the 12s i think i will just concentrate on the body of the car. and you guys can keep that in mind if you are in the NY area and need some body work.....i'll hook you up if you drive an RX-7 thanks guys.

Jeff

CantGoStraight

The "AST" or (Air Seperation Tank) is in the system to purge air from the coolant system. The stock one is plastic and the seam is known to split of seperate without warning dumping your coolant and allowing the system to loose pressure and boil over, in most case's overheating the motor.

Mpressiv

oh i see....that sucks. how much will it cost to replace the AST?
so for the things that i should do before i mod the car are:
radiator, AST, silicone hoses, boost gauge, turbo timer, and blow off valve. is there anything else anyone can think of? i just dont want to mess something up i want to just get all that stuff out of the way as soon as i get it. and then i will spend my leftover money on other mods and save some for "just in case"

CantGoStraight

AST can be purchased at Pettit racing for $149 he will throw in some other goodies such as the ground strap upgrade (another thing this car is noted for) Don't forget your boost gauge and down pipe....looks like your on the right path. Enjoy the car.

Foz'sRX-7

Replace the AST with an Aluminum one from Pettie Racing. Mine split while I was going to Dr about 18 mos ago. I was very fortunate to come out of the Dr's office and notice the puddle under my Rex. It only cost me a new raduiator and AST. But they put a new plastic one back on.. I now have the Alum from Pettit. I don't want to get caught on the highway when it blows.

Next you should absolutely replace your hoses and vacuum lines with silicone. By now your OEM's are as hard as a rock from being baked by the heat of the engine.

After that you can add upgrades slowly, making sure that you are running fine before each upgrade. If something goes wrong you only have to back off the last upgrade. I would suggest a Turbi Timer and boost gauge then a Cat-back exhaust. Drive it for a while and get used to te changes. Then go with a 3" down.

Later, change out your pulleys, get the 8.5# flywheel and replace the clutch. Next add a Boost Controller, & on & on & on, depending on where you want to go with it.

Remember, it's only money and it's such a rush to drive!