Grunswald

Hi, for the moment my fc is in stock condition and has done a little less than 140000 km. I just got my exhaust replaced (the previous one as leakage). I got read of the silencers and the catalyzer. I'd like to have your advice on what i should do next.

My plans are:
- stage 1 excedy clutch (mine is completely dead)
- apexy intake.
- removal of air pump
- new power steering belt (mine is incredibly loose)
- cleaning of the grounding points
- new o2 sensor
- new coilover (probably zenky racing or driftworks)
- new wheels (yeah it's good to parade sometime )
- cusco strut bars (probably the 4 of them)

what i've heard i could need:
- Fuel cut defender : do i really need it ? a friend told me that it would be necessary as i removed the catalyzer ? is it true ? isn't there a risk of overheating the engine if i install one ?
- New fuel pump : the seller of the car told me there was issue with the pump while mass transfer, for example when going through roundabout. I haven't noticed it so far but as my clutch is sleeping i guess i didn't really do some heavy driving. I heard some really bad feedback about the walbro pump and i can have some interesting discount. you know if there is a good replacement pump from bosch ? or is it a better idea to go with the Rotary Performance pump ?
- apexy power fc : but i'm really bad at mapping, and i'm not sure the people that i know that are good at it know how to perform it on a rotary engine.
- AFR gauge + wideband sensor : i thinks it's essential to work on the mapping.

I'm not looking for a monstruous car for the moment, i'm looking at a maximum of maybe 250hp (so far if there wasn't this clutch issue, i'd be happy the power of the car). I'm more looking to get the car a bit more reactive in term of handling and thrust.

Please tell me if you think some of my planned mods are not necessary or should be priorized (the clutch is the next one coming, for the rest i have no priority) or if you see something that should be added to the list
Thx

Aaron Cake

iTrader: (1)

The stock ECU cuts fuel at 8.6 PSI of boost. A FCD allows you to get past this. HOWEVER, the FCD does not increase fuel flow, so if you intend to run much past 8-9 PSI, you'll need additional fuel mods. Your friend was a bit mixed up in the sense that running too much boost with just an FCD will run the car lean, blowing the engine.

It is likely that the baffle inside the tank has come loose, or the fuel pickup sock is clogged.

Walbro pumps are fine. But adding one will raise fuel pressure so you will need an aftermarket regulator.

I don't know the PowerFc.

Yep.

Evil Aviator

The Apexi air filter is very good, but it only lasts about 15,000 km before it needs replacing, depending on how much dirt is in the air in your area. I prefer filters that can be cleaned and re-used, such as the K&N brand that is good for 10 years or 1.6 million km. Regardless of the brand, cone type filters will suck in hot air from the radiator if you do not fabricate a divider or air box for them. Also, you can save money by making your own kit with a filter, hose clamp for the filter, an additonal small filter and zip tie if you retain the air pump, a mounting bracket for the AFM, and an AFM adapter is needed if your car is an 87-88 model. If you want to save time and money, a regular stock type filter will work fine if the engine is running close to 200hp.

I would leave the air pump alone if it still works. Removing the air pump will not save much weight or increase horsepower by any significant amount, and it will cause popping noises to come out of the exhaust when you let off of the gas pedal. If your car is an 89-92 model then removing the air pump will stop the VDI system from working, resulting in a loss of torque or horsepower.

Strut bars connect the struts to each other, so there are only two: front and rear. Rear strut bars will interfere with the area inside the car, so most people only use the front strut bar on a daily-driven car.
http://www.corksport.com/86-91-rx7/f...spension-mods/

Since the exhaust upgrade is your only significant modification, you can simply buy a Rtek upgraded ECU. If you do this, then you will not need the fuel cut defender, AFR gauge, wideband O2 sensor, boost gauge, or Apexi Power-FC. Here are links to the Rtek website and section of this forum:
http://www.pocketlogger.com/index.php?pid=rtek7
https://www.rx7club.com/forum/forumdisplay.php?f=168

Even if you don't need it for tuning the engine, a narrowband or wideband AFR gauge is still a good idea in order to monitor your engine so you can watch for fuel problems. A narrowband is less expensive and hooks up to the stock system, but is only accurate around the 14.7 AFR range. The wideband is more expensvie and requires you to mount an additional O2 sensor in the exhaust system, but it is accurate throughout the AFR operating range.

Bosch pumps have a more linear output and are made to a higher quality than Walbro pumps. However, many people on this forum have used the cheaper Walbro pumps for many years with no problem. I recommend the high-quality Aeromotive and SX brand fuel pressure regulators. Unfortunately, these aftermarket regulators are not direct fit items, and you will need to have them installed by a professional if you are not a good mechanic.

You may want to replace the fuel pulsation damper if it is the original part. If you have an 87-88 model then you can use a banjo bolt in place of the damper if you are using an aftermarket fuel pressure regulator with a built-in damper, such as the Aeromotive and SX models. Another option is to use an aftermarket damper, but like the aftermarket fuel pressure regulators, a professional mechanic should perform this modification.
http://www.mazdatrix.com/c-pulsation.htm

Grunswald

first thing first, thanks for the useful reply

in order to clarify somepoint, my car is 91 fc turbo II.

I thought it would be fine to remove the air pump as i've no catalyser (catalyst ?) anymore. although i believe i already had popping noise before during warm up.

for the strut bar, i included the lower arms as in french it's the same name for strut and lower arm (i believe).

Never heard of the R-tek solution, but it seems really interesting for what i want to do... i read that it remove the warm up procedure used to "warm the precat". I don't have a precat anymore, so it's fine for me to start the car with the gearbox in 1st to bypass this AWS so ? if so my neighbors will be really happy...

If i regroup your answer on the fuel pump :
- Walbro pumps are actually not bad
- if i change my pump in need a new fuel pressure regulator
I didn't think of it before, but will it increase my fuel consumption ? as long as i drive as before changing the pump, it should not change anything i believe.

for the fuel pulsation dampener, i'll check if i have leakage and see if i have to change it.

for the air filter, i had an apexi one on my mx5 (replacing my k&n that caught fire ) and it wasn't dirty after a couple of year. but that's a good point, i'll check what k&n solution are available. I think i will go with kit, install it and then see how to install a wall around it. Maybe it's feasible to use the same fixation as the one for the original air box...
I'm not looking to increase the power like this, but more to increase the "roaring" factor of the car

Evil Aviator

The Turbo II doesn't have VDI, so there will be no performance loss with the air pump removed. Here is an example of the popping noise:
http://www.youtube.com/watch?v=6bY89...eature=related

Upgrading the fuel pump will not change the fuel consumption of the engine as long as the fuel pressure is kept within limits.

A cone air filter will fit directly to the 1991 airflow meter. I think the diameter is 2.5". You only need to buy a kit if you don't want to build a mounting bracket to support the airflow meter once the stock air box is removed. However, the cone filter will suck in hot air unless you make a custom divider or air box as I mentioned earlier.

The Cusco lower strut bars are not very popular among racers, and they would be overkill for a street car. Most racers do not bother stiffening the lower body, but those who do usually choose the AutoExe kit or a similar custom design.
http://www.rhdjapan.com/autoexe-memb...set-fc3s-55495

Grunswald

ok, i'll keep the lower bars for when i'll win the national lottery

I'm a bit sad with the backfiring, i'd like to have it i've had some when i change my exhaust but now that i putted the sound dampener ( don't know if it's called like that) in the muffler tip, i think it doesn't do that anymore... on the plus side, the cops are not running after me anymore

and for the air filter, i don't have much spare time and i just have a small garage. Moreover my rx7 is my... daily drive... yeah i know, that's stupid... so if change something and find out that there is something missing i can't leave the car as it is and work back on it once i got the missing parts... that's why i'll go for the kit, like that i know that it will fit and i will be able to drive the car and then work on the divider on the side. is it absolutely necessary ? as the conduct for cold air from the old air box will remain and blow cold air on the cone when driving.

Grunswald

Hi all, yesterday i was searching were to get a clutch at the best pric and found something that creeped me out...
Apparently the stage 1 excedy clutch (which was my initial choice) is not able to withstand the torque delivered by the stock turbo 13b. cf this topic https://www.rx7club.com/2nd-generation-specific-1986-1992-17/exedy-stage-1-clutch-power-limits-862817/

If i understand well, the minimum should be a stage 2 or 3 clutch ?
seems weird to sell a stage 1 weaker than an oem one...
or maybe if you know a clutch that will fit my needs better, feel free to say it, that will helpful

Grunswald

Sorry to repost but i really need an answer. I'm starting to think differently.
I'm not planning on adding much more power than the stock engine and the original clutch did 140 000 km. Is it really necessary for me to get a stage 1 or an OEM version should be enough ? it's not the same price at all, so if i don't need it... can i have your mind on that ? another point, do you know the duration set by mazda for a clutch replacement ? My garage didn't find it and they'll use it to determine the price of the installation... I like to do it by myself though, is it really hard ? keep in mind that i'm not really well equiped and not really well trained

Evil Aviator

If you like the Exedy brand, their regular Stage 1 kit (10803A) is good for up to 237 lb-ft wheel torque, and their HD Stage 1 kit (10803AHD) is good for up to 296 lb-ft wheel torque. Exedy describes wheel torque as about 20% less than engine torque. I would estimate the peak engine torque on a 250hp non-ported 13BT at about 215-220 lb-ft.
http://www.atkinsrotary.com/store/home.php?cat=764

The life of the clutch depends on how you drive. A stronger clutch will not last any longer than the OEM clutch.

I would not recommend trying to change the clutch yourself because you could ruin the engine or transmission if you bolt them together incorrectly. Also, the clutch will fail if you get any grease on it.

Grunswald

hum ok so a stage 1 is enough but i could also keep an OEM one....
And for the installation, i'm a bit ashamed but i will have it installed in a garage.
You know the admissible torque for the OEM clutch ?

Evil Aviator

I do not know the torque rating of the OEM clutch, but it is probably close to the Exedy Stage 1, maybe less. Personally, I would choose the Exedy HD clutch over the regular Stage 1 or OEM clutch for the estimated torque of your engine. Another option is the ACT Street/Strip clutch, which is rated for 330 lb-ft torque.
http://www.rx7store.net/product_p/z65-hdss.htm

There is no shame in choosing a professional to work on your car. That is actually the smart choice with maintenance that requires a high degree of technical skill and/or expensive equipment.

Grunswald

the web link doesn't work for me and when i search the site, i only find rx8 clutches. Is there something to do to have the full list ?

Evil Aviator

You can go to the ACT website and search for products if you enter your vehicle year, make, model, and engine. The two street clucth kits are Z65-HDSS and Z65-XTSS.
http://www2.advancedclutch.com/home.aspx

Grunswald

wow... those are expensive... i'd love to go for this one but i have too much taxes to pay this month lol.
I've found what i believe is the exedy kit you are talking about on ebay :
http://cgi.ebay.com/ebaymotors/EXEDY...item2a0b559ad5
Is it this one ?

Evil Aviator

Yes, 10803AHD is the correct part number as per the Exedy catalog. However, there are many fake copies on Ebay, so I would recommend that you buy from a legitimate dealer.

Exedy catalog link here:
http://www.exedyusa.com/catalogs/2010SportsCatalog.pdf

The clutch is expensive because the kit also includes a new pressure plate, release bearing, and alignment tool.

Grunswald

ok, i believe if i buy a 10803AHD branded as "for rx8", it should fit my car as well , normally ? (sorry for asking this stupid question, but if i buy a wrong one, i'll be pretty much fucked...)

Evil Aviator

I am pretty sure they are the same part. I suggest that you ask Exedy to make sure. Exedy has telephone numbers and email for such questions, and they are very supportive of the rotary community.
http://www.exedyusa.com/oe/contact

Grunswald

i've finally found it at black halo racing. I ask them if it was ok and the guy answer with a really detailled answer (size of the disc, size of the housing, comparison with the rx7 one, etc...). It's nice to find someone selling parts that actually know about them . And the price is pretty decent as well : 426$ delivered in france. i believe that's the cheapest i could find. So when i get paid, i order it right away

Grunswald

Hi,
just a little update, i received my clutch the 23rd and normally i will have it installed this week.

I think i will go on cheap mods for the moment to try save a bit... i'm thinking removing the air pump (with the installation of the dual alternator belt pulley and small water pump pulley as well) and the fuel cut defender. For the FCD what do i need more to install to have it running without risking blowing up the engine ?

Evil Aviator

The pulley size should match the purpose of the car. The standard size pulleys are made to cool the engine and power the electrical system in the street driving engine rpm range, but the water pump will cavitate at higher engine rpms common with ported racing engines. The underdrive pulleys are sized to work well on ported high-rpm racing engines, but will not supply an adequate water flow or electrical flow at lower engine rpms common with street cars. If your engine is not ported, and your car will be driven on the street, then you should keep the stock pulleys.

From Racing Beat:
http://www.racingbeat.com/mazda/perf...r-cooling.html
"Note: We do not recommend either the Single or Double-Sheave Main Drive Pulley be installed on engines that are typically used for "stop and go" street driving: however, if your engine is commonly run up to 8,000 RPM, our Double Sheave Main Drive Pulley will prove beneficial. In general, do not use our Double Sheave Main Drive Pulley on 1987-91 Turbo II engines unless modifications have been made - shorter intake runners. etc. - to increase the engine’s RPM range substantially. Turbo II engines produce their peak power in a lower RPM range, relative to their non-turbo counterparts."

Along with the FCD, you may want to also install an upgraded fuel pump and fuel pressure regulator. You should at least check the voltage to the stock fuel pump:
http://fc3spro.com/TECH/MODS/preliminary.htm
http://fc3spro.com/TECH/MODS/FUEL/fpump.htm

Personally, I would choose an Rtek ECU upgrade rather than a FCD, assuming that your car has an N370 ECU. The Rtek ECU upgrade is not very expensive, and it has the FCD function as well as other nice features. Also, an FCD requires an aftermarket boost gauge, while the Rtek will work with the stock boost gauge. If you think you will need larger fuel injectors, then you can buy some 720cc injectors and use them along with the Rtek 1.7 or 1.8.
http://www.pocketlogger.com/index.ph...age=1&ecu=S5T2

Grunswald

you're absolutely right, i completely forgot the Rtek would replace the fcd.

for the pulley, i watched on rotary performance and they don't say anything about issue at lower rpm. thanks a lot on warning me

So Rtek, dual alternator pulley (i really want to remove the air pump, there are way too many thing under this bonnet) and lots of belts as mine ar a bit loose lol.

Concerning the rtek, i believe the stage 1 is enough for me. 550cc are the stock injector i believe ?

i have to clean my grounding point, but i'm waiting to receive my new headphone to have music while working lol

Evil Aviator

The 2Gen RX-7 alternator is weak. Many people have had problems with the electrical system cutting out at low engine rpm when driving at night with lights or when powering a large stereo system.

I would leave the air pump and alternator alone unless you can find a stock-sized dual pulley system. The air pump doesn't weigh much, and it only uses about 1 hp.

It sounds to me like Stage 1 would be fine for you. You can always sell it later if you decide to upgrade to a full standalone EMS.

Yes, stock is 550cc.

Here is an approximation of potential horsepower, assuming the fuel pump can handle the flow:
4 x 550 = 210-260bhp
550/720 = 235-290bhp
4 x 720 = 260-330bhp

LOL

Grunswald

it's not really to gain power or save weight that i want to remove the air pump. It's more that it's useless now i have a decat exhaust and i would save some place under the bonnet (that is amazingly crowded)... The dual pulley from rotary performance wouldn't work ?. For the alternator, i'll do the voltage check and see...

canonize-ryda

i was a noob when i changed my clutch for a stock hd clutch.. took me 2 days but working a few hours each one and i changed my own clutch no problem. i had my uncle help me since he new more about dropping trannys then i did.. and here i am a year and half later no problems yet with my clutch.. and i didint even change the pilot bearing

Evil Aviator

The Rotary Performance pulleys are underdrive. If you want the correct drive speed for a street car then you will need to get pulleys that do not underdrive.
http://www.tweakit.net/shop/product_...roducts_id=111