Need some opinions on mods.
 

For starters, heres my car:
- 94, 70k on original motor and turbos
- 10-7-9ish boost pattern
- only mod is a downpipe
- 2k mile oil changes
- only issuses so far are a leaky rear main seal (bad clutch as a result), and some rear suspension squeaks and clunks
- also, under WOT, the secondary turbo seems to sound funny... and theres a little more oil in the intake than i would like
- the idle also dips sometimes when coming to a stop light or just reving at a stand still

SOOO..

Im about to start my next semester in college and my housing didnt work out, so now im left with a 35 minute drive everyday.

i know i need to get the compression on the motor checked before anything, but i would like some input, since im sure theres someone here that has gone the route im considering.

additions:
- PFC
- profec b
- hose job
- alum ast and rad
- ast s/s clutch
- delrin diff bushings if i can find someone with them from that group buy.
- full intake and exhaust
- a new set of turbo's, low miles, and maybe go non-seq but im undecided on this.
- undecided about a IC, but if do get one it will only be a stock replacement.

removal:
- main cat, and cat back
- air pump
- emissions (double throttle, AWS, etc..)

i have a couple of reasons for wanting to go with a set of turbos now rather than later: first off, the longer i wait, the harder its going to be to find a decent set (although there will always be someone going single or ls1). second, mine are still good. so if anything goes wrong with the new set, ill always have mine on hand.

i want to run stock pressures, 10-8-10 if i stay sequ and 10 or 12ish if non-sequ. the only thing stopping me from going non-sequ is that it seems there isnt a real concrete answer to where my boost will come in. if i could hit 10psi by 3000-3500rpms, id be okay with it as long as its not an extreme surge of power when it kicks in.

so id like to hear what you guys think about this potential set up, if im missing anything, and if you think its relatively safe on a 70k motor (depending on the comp. test). ive had my car for almost 2 years now, and ive done TONS of reading on this forum.. but its just that.. reading. you guys are the ones with the hands-on experience with these cars.

a very good friend of mine owns a machine shop that i used to work at, so all my tools and mechanical needs are taken care of, even the welding/bending/machining parts. we did my clutch and downpipe replacement in a few hours and neither of us had been under an rx7 before, so i feel pretty confident we can take care of most of the things i listed, and PFS is only about an hour away if something decides to go completely wrong.

also, do you think is is do-able with a 2-4k budget? ill be doing all of the work except the tuning.

EDIT: wow i didnt realize how long that was when i was typing it, sorry about that.

don't you think would be wise to fix the suspension/turbos/engine up to par before modifying it?

yes i defiantely think so

the diff bushings are my only suspension woes, the turbos im planning to replace, and the idle issue is the only thing that i havent quite figured out yet, but its not a very predictable occurance, it seems to come and go which makes me think its not really something related to the internals.

and honestly, the idle thing really isnt a big deal. when i say 'dip' im talking about like 100rpms MAYBE. but its noticable.

edit: oh are you talking about the rear seal? i already fixed that awhile ago when i changed my clutch and downpipe. sorry i forgot to mention that.

I don't know what your financial situation is,but I wouldn't start modifying it with 70k on the original motor..I know some motors last longer than that,but don't put all your money into mods and then find out you need a rebuild..

^thats exactly the question i want your opinions on.

if these mods are risking too much with the motor, then of course i wont do it. im hoping to get a compression test done this week.

i dont track or autox the car. occational highway pulls, and i try to make it a point to hit redline in 2nd at least once everytime i drive it.

if you noticed, there not a mention of horsepower. im not looking for a number. a little more power would be nice, but overall i just want to clean everything up a bit. like how much more simple non-sequ with intake/exhaust is.

my financial situation: my college tuition and room and board are free, so i was given a relatively blank check to take care of my car. an alignment, new tires and brakes are already on the list.

Well,adding more power is going to put more stress on the motor,period..So I would definitely try to find out the condition of the motor..Then I would do the reliability mods,and I would slowly mod from there and see what you like and don't like..And as far as sequential and non-sequential goes,non-sequential will clean up your engine bay a lot and make troubleshooting easier,however I think it makes the car less fun to drive..If you are going to daily drive it,I would stick with sequential;I think you will regret it otherwise..

All of that is probably not do-able with that budget. Plus I wouldn't shoot my wad all at once. Keep some in reserve for when something unexpected happens. If you're not after big HP numbers, skip most of your listed mods.

Do the suspension bushings. I'd recommend using stock bushings or the poly urethane ones that wanklin sells. Delrin is stiffer and you don't always want that on a street car. Search for some posts from max cooper in the Suspension section as well as howard coleman. Get some tires if you need them and get an alignment AFTER all of that is done. Use the Pettit alignment specs (FAQ thread). If you're not doing labor on bushings yourself, it will get expensive.

Regarding the cat, Unbolt the front of the cat where it meets the downpipe and shine a flash light in there to check if the cat is getting clogged. A clogged cat kinda looks like a shower drain clogged with hair. A good cat will have a mesh honeycomb looking structure. If it ain't broke don't spend your money buying one. If its clogged, get a high flow cat from some place like GothamRacing.com or rx7.com. Also get new gaskets. I suspect you have a clogged cat as I had the same symptoms when it clogged up.

Removing the cat is a big mod and cann often result in a blown motor if boost control precautions aren't taken. If you decide to get a mid pipe (which is pretty loud and annoying IMO and smelly too) you'll want a good boost controller also.

A radiator is good to have. An AST is a must. So is fresh coolant. Its probably a good idea to replace the radiator hoses that are easily accessible since they are pretty old at this point. Re-use or buy new factory hose clamps. Regular worm clamps will chew up a rad hose over time (ask me how I know...). Maybe do a new thermostat since you are there. Oh and don't forget to try and do the turbo coolant lines. You need to unbolt and more (or remove) the air pumpt to get to them. DamonB had some good info about these hoses might want to search for that.

Change the Tranny oil with Redline MT90 (mail order only usually try hrpworld.com) and diff oil with Redline gear oil (available everywhere). Or try NEO if you can find it.

I wouldn't bother with turbos right now. Do them if they blow or after the motor gives up. If the motor lets go for some reason, the apex seals may take out the turbine blades so why bother doing it now on a high mileage motor. Once you're out of college and get a good job, you'll be able to afford a set of NEW 99 turbos, BNRs or whatever.

I'd definitely do an upgraded SMIC. Get new silicon couplers and the high quality hose clamps to avoid any future problems. Maybe do the Efini Ypipe if you feel like instahlling it.


Cat: ~400-500
Radiator: ~400
Coolant hoses: ~160 for the full kit from Malloy Mazda
(you don't want to buy the above stuff used)
AST: ~100
Full rear stock Bushings: ~360
Alignment: ~100
Thermostat: 30
Coolant and distilled/bottled water: ~20
Tranny/Diff oil: ~50
used SMIC: ~500
new silicon couplers for intercooler: ~7 each
high quality clamps for the couplers: ~5-10 each
Efini Ypipe: ~200

Thats about 2,500 right there not including tires or other stuff you might need. Don't forget your regular maintenance: fuel filter, NGK plug wires, spark plugs. Thats another 150.

I'd be careful if you want to try the vacuum hoses. Lots of people don't get it right the first time or break solenoids while they are trying to "upgrade" and wind up with boost control issues. Its a bitch working on the rats nest and shit happens. I'd say if it ain't broke don't fix it - unless you see some hoses that are blatantly fucked.

Regarding your idle, try adjusting your TPS. See the FAQ for Damian's thread.

Good luck.

An irrelevant question....where do you go to school? College Park by chance?

Your idle drop at braking may be a bad check valve inside the vac line comming off the brake master - the hose kit is about $25 at the dealer

^yeah college park, but i have to commute this semester.

gracer7-rx7: thanks for your input, youve actually changed my mind.

the one thing i didnt think of is that if the motor does go, it could take the turbos out with it... not something i am willing to risk.

so staying sequ, with the original turbos...

the only thing im worried about now, is exactly what you said... screwing up the hose job. i love the sequential system to death, but it just seems to fragile sometimes. the last thing i want is boost creep that i have no idea the cause of, or a blown motor because of a sticky or blocked hose or valve.

one thing i definately want to use in my setup if i take out the main cat (after the PFC and boost controller) is some sort of emergency pop-off valve. a mechanical valve on an IC hose where i set it to 2-3psi over, and if it reaches that point, all pressure is let out through the valve. so even if something does screw up, i can possibly save the motor.

im sure my guy at the machine shop could definately design something for me if one doesnt already exist... but ive never seen or heard of one so i wouldnt know. is there something out there like this already? would there be any downside to such a method?

well its not always at braking. i really cant re-create the symptom. the closest ive gotten, is when the motor is well warmed up, and i come to a stop light. it wont drop while im moving (even if im braking), only when i come to a complete stop. if i sit there at the light and rev it a little, it will drop as well. it doesnt matter if the car is in gear or out of gear, cluch in or clutch out.

... and sometimes it wont do it at all.

someone suggested the dash pot at one point.

Some advanced boost controllers do that. I have a profec E-01 digital guage / controller that you can set to do exactly what you want. I had it on my old car but with the new car with just twins I havent put it back on. Check it out if you're interested I'd certainly sell it as it's doing me no use sitting in a box.

Yes the hoses, solenoids and electrical harness get fragile after this many years and mileage. On my car, pretty much all the solenoids are new as are the turbos and wastegate with the 99 twins. Electrical harness was replaced with one of my motors at ~100k miles. It was progressive repairs that got me here over time.

The hoses don't really get sticky or blocked, they'll crack and not hold vacuum. Solenoids often fail internally due to the heat or the nipples crack when trying to replace the hoses. :)

An easy way to get over the threat of over boosting or creeping, is to use a good boost controller and keep a cat in the exhaust stream. I used the boost controller on my mostly stock FD and it helped control some boost spikes I was getting due to a worn out solenoid. The car had a cat also. Old skool Greddy Profec B is what I like to use but the new Spec S looks easy to use also.

If you hang out here on the forum too long you often start getting overly paranoid about stuff. ;)

There are a fair amount of FDs that made it to very high mileage on the original motor b/c the owners maintained them well and had some luck.

ok so dumbing the list down a little... (still doing hose job, gaskets, clutch, bushings etc)

basic list: intake, exhaust, boost controller, maybe smic.

i know this is a pretty elementary setup here on the forums, but better safe than sorry...

so now i get to decide my boost control. it looks like many people are going with greddy products, but i want to explore other options.

is the PowerFC boost kit readily available? if i get the PFC as well, it would be nice to control everything for the commander. ive been reading about it all morning and it seems theres mixed feelings about it here on the forums. some say its no good, some say its all in the tuners experience.

https://www.rx7club.com/forum/showth...threadid=32228

also, quick question about 'keeping a cat in the system'. i really didnt want a cat in there because of the exhaust i wanted to fab up. i wanted to weld up a borla xr-1 in the midpipe section of the exhaust, and then weld up a Y collector into two 3" pipes as the catback. basically a better looking and sounding dual N1 setup. i hate the look of 8" round cans hanging off the back of the car.

i know the cat makes a huge difference, but is having a cat really going to mean the difference between having boost creep and not? and im not willing to just hope i have a little 'luck'.