Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: jazraymcbeath on June 03, 2005, 12:10:34 PM

Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 12:10:34 PM
hi i am seriously thinking of selling the cossie to get an rx7 but i am getting put off by tunnig cost and petrol consumption and reliablity can you give some facts and figures

to compare my cossie is detunned to 286.3bhp with 279 lbs of torque  and weighs 1240 kg with the gtech meter i can get 0 to 60 in 4.81 sec and quaters in 12.9 sec and with stage 3 0 to 60 in 4.51sec and quater in 12.02 (and enough to do away with a p1 scoobie and  600 bikes) i can put in  10 pound drive sensible and get 70 to 80 mile if driven hard will get 40 miles to my tenner and petrol here is 92 pence a litre the car was running stage 3 about 340 to 350 bhp (conversion cost about 600 pound) but took of as was off as was skint that month and was only getting 26ish miles to 10 pound as the car is driven hard more than sensible i use my car everyday it needs to be reliable and the cossie is that i have had 6 now there that good

how dose the rx7 compare to above as want to try an rx7 but dont want to sell the beloved cossie and be dissapointed i would want the same sort of performance as above but if this cost more than 1500 pound to get that performance and reliablity i  would prefere buying a cossie engine for 1500 and sticking that in and having reliable power in a very pretty cossie powered car as no one knows what a cossie is anymore but when i am driving my girlfreinds integra type r you get plenty of attention

thanks
jaz
Title: cosworth vs rx7
Post by: iaint on June 03, 2005, 12:50:04 PM
If you have to ask what mpg you\'re going to get from a tuned FD then it\'s not the car for you.  Simple as.

If you get past the fact you\'re looking @ 14-20mpg depending on how/where you drive then you\'re (in my biased opinon) looking at one of the best cars you can get for reasonable money.

You don\'t mention budget and that\'s the real thing that\'ll limit the quality and state of tune you\'ll get.

- You can get a stock car and mod it which is the expensive option but you know how well everything has been done.

- You can get a modded car imported. Cheaper than modding yourself but you don\'t have the full knowledge of the car.

- You can buy a decently tuned, rebuilt example from a club-member and know exactly what you\'re getting.

In terms of mods and power it\'s a varied bag.

You can uprate intercooler, fuelling, rad, etc. but keep the standard twin-turbos and get upto around 350-400fwhp or you can go single-turbo and get 350-500 fwhp.

Personally I\'d be looking to get something with a recent rebuild or a dead engine and factor the cost of rebuild into the price for peace of mind.  you could buy a higher mileage car and it might well last another 20k+ though.  The rotary engine isn\'t all that unreliable!

Get along to a meet and talkto a few owners - always the best way to find out a bit about the cars...
Title: cosworth vs rx7
Post by: MikeLMR on June 03, 2005, 12:52:20 PM
if you want cheap power an rx7 isn\'t probably isn\'t the car for you.

as for fitting a cosworth engine for £1500 ?! I\'m not even sure it\'d fit due to the steering rack being high on the rx7s + its going seriously screw up the handling due to the weight of what is basically a 16v turbo\'d pinto.
Title: cosworth vs rx7
Post by: MillSpeed on June 03, 2005, 12:56:37 PM
There\'s no doubt you can get some scary power out of the baby rotary, but I think it\'s widely accepted that 7\'s are expensive to maintain, expensive to run & are a handful to drive! But they are so much fun. I think alot of the 3rd gen\'s bad rep has come from people just not looking after them properly and treating them like a piston engine. The rotary can be built to last, it just takes a bit of planning and, most important of all, proper tuning on a rolling road by a rotary specialist. The car left the factory with a lot of compromises (i.e the cooling system and rediculously complicated sequential turbos), all of which can be improved upon. Can an RX7 be used as a daily driver? I certainly think it could, just with a bit of groundwork to address some of her \'issues\'.
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 01:25:24 PM
a budget of about 5k i am a mechanic to trade so was looking for a car needing work but what i am getting at is i dont mind rebuilding the rotary engine and looking after it as long as it dose not turn round an sting me if the rx could acheive 14 to 20 mpg i could live with that what sort of lsd dose it have and when it starts to oversteer is it progressive or dose it snap

 but dont no if i want to take a chance with the rotary when i could of stuck in a cossie lump as i have seen a pinto in a  mk1 rx7 and rover v8 and american v8 so surley a cossie with a modded sump if need would be a simple fit
Title: cosworth vs rx7
Post by: Top_gear_towers on June 03, 2005, 01:36:43 PM
From reading your post, I think mpg is important to you. That you detuned your Cossie to get better mpg says, to me, you should rethink an RX7 purchase.

No doubt this will be frowned upon, as the larger the club is the better - but I can only speak for myself.

The MPG on the RX7 is nothing short of depressing. I seem to forever be in a petrol station, and my wallet has definitely taken a hit from the monsters constant Optimax thirst.

Around town is not bad at all - but once you hit the motorway on  a long trip, prepare to start looking for Shell stations from the start.

I drove from London to Birmingham and back in my E46 3 series, and used a little less than 1/4 tank.

Did the same trip in the Rex and used an entire tank (and I wasn\'t driving like a loony).

Take as read the RX in an amazing drive, and turns heads like little else.

But once you\'ve put it to sleep and the lights go out, its just you and your wallet baby.
Title: cosworth vs rx7
Post by: iaint on June 03, 2005, 01:44:01 PM
QuoteOriginally posted by jazraymcbeath
a budget of about 5k i am a mechanic to trade so was looking for a car needing work but what i am getting at is i dont mind rebuilding the rotary engine and looking after it as long as it dose not turn round an sting me if the rx could acheive 14 to 20 mpg i could live with that what sort of lsd dose it have and when it starts to oversteer is it progressive or dose it snap

Could be wrong but I think it\'s a Torsen lsd but my memory may be playing tricks on me there.

In oversteer it\'s very, very progressive indeed - if I can catch tail out moments then it can\'t be that bad.  A heavy right foot in the wet though and you\'d better be sure you know what you\'re doing and autumn/winter always sees a spate of posts from people who\'ve stacked their rexes!

Not sure how it compares to other rwd motors though - from talking to people it\'s the transition period where the secondary turbo comes online that catches many people out - a hike of 100+ ponies over a few hundred rpm can do that if you\'re not used to it or not concentrating!

As you\'re a mechanic you should be able to do most of the work on your car - there\'s a vid doing the rounds that shows you how do rebuild the engine.  The only really complex part of the FD is the turbo control mechanism (\'rats nest\') but this can be simplified by going non-sequential or single turbo.

As for the conversion options - don\'t - you\'ll spend more doing it than a rebuild or two and you\'d be missing out on the thing that really makes the FD shine.
Title: cosworth vs rx7
Post by: MillSpeed on June 03, 2005, 01:45:47 PM
The RX7 is fitted with a torsen LSD as standard. I think alot of the people on this forum will testify that the 7 will stick like sh*t to a blanket, but when she goes...she goes!
A Cossie lump in a 7 would definately be interesting, give it a go and see what happens! Don\'t froget to take lots of photos.
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 02:03:40 PM
what sort of money should i expect to pay for a rex in need of engine rebuild and where do i get my hands on this video on rebuilds what mods are there if starting with a clean slate for a strong reliable engine are the stock radiator and intercooler up to the job cause if you uprate the intercooler you are taking away from the radiator as ther is such a small open surface are at the front of the rex
Title: cosworth vs rx7
Post by: MillSpeed on June 03, 2005, 02:21:10 PM
In my opinion, the stock intercooler is woefully inadaquate...it\'s tiny! But like you said a large front mount will restrict your airflow throught he rad. I\'ve just bought a large PWR charge cooler, and I\'ll be moving my battery to the boot so you can sit the rad more upright and hopefully get some more flow through it. With any luck, the heat exchanger up front will restrict the airflow less than a FMIC. Gonna fabricate some proper ducting too, to make sure all of the air that goes into the \'mouth\' actually goes through the rad. You can buy uprated aluminium rads which are much thicker and will mount in the stock location. You might also consider changing the cars nose. I\'ve got a FEED Type-II front and the radiator opening is much bigger.
Title: cosworth vs rx7
Post by: rxv8 on June 03, 2005, 02:28:50 PM
i say DO IT..stick a cossie lump in there would be real interesting..i am pretty sure it would fit no probs,i have a sbc 5.7 in mine and theres plenty of room...pm me if ya want a chat...or pm me ur msn address...cheers:wave
Title: cosworth vs rx7
Post by: gsb876 on June 03, 2005, 05:11:39 PM
I sold my Skyline and Escort Cosworth to make room for the RX7 and do not regret it, Cosworths are great cars but the rx7 is so different to drive and handle its worth the jump, if you are not bothered about a rebuild there are plenty of low cost rx7\'s open to you, i think the rebuild kit is £1500 and i\'m guessing you will be doing the rebuild yourself.
Title: cosworth vs rx7
Post by: John Yorke on June 03, 2005, 05:21:15 PM
Hay Mate

To be honest you are not interested in a rotary, best thing you could do is go and buy an engine to fit in yer cossie, why buy a rex and fit a different engine:confused: :confused: Waste of time:reallymad
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 05:28:58 PM
yes will be rebuiding myself and cant wait till get a wankle in bits(if sticking with the wankle)
since you had a cossie (what type and state of tune) we can use that as a bench mark for handling acceleration top end etc how did it compare
Title: cosworth vs rx7
Post by: rx7veilside on June 03, 2005, 05:44:49 PM
i had a 3 door running high stage 3 and it pulled nice but in comparison the difference was between ur perception as a small car will allways seem faster but i wld have to say a moderatly tuned 7 will dump all over the cossie on the street due weight proportionate to power and a highly tuned 7 is quite frightening and not to be abused or it will bite ur arse..looks wise the 7 gets u stopped at lights and people asking what it is
Title: Why RX7 and not Cosworth
Post by: eatmyrx7dust on June 03, 2005, 05:52:04 PM
When you own a RX-7, part of the joy is explaining to complete strangers, who approach you in petrol station forecourts, pub carparks, supermarkets, if fact everywhere all the time, that the car infact has no valves, no pistons, no cams, yes its only a 1300, yes it does look gorgeous, it has 255-280bhp stock.

Does this happen to cosworth owners ?? and you can\'t stick an rx-7 badge on a mx5 and pretend its a rx-7 !!
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 06:14:14 PM
sounds good to me i hope i have found a replacment for the cossie thats as good and hopefully better

its hard living here as there isnt any 3rd generation rex owners to stop and ask and get a blast in there car

all i need to do now is get hold of a rex does any one know of any or is it best to import whats the best option so i can have a rex  on the road for 5k that just needs maintained i dont mind the work as long as i have a finished car for 5k
Title: cosworth vs rx7
Post by: Freddy on June 03, 2005, 06:36:20 PM
Slightly off topic;

I have an RX-7 which has had a rebuild recently. Ltd edition type X in manual with all the small comforts. Car drives well with no faults to report.

Looking for £5900 ono.

Or if you\'d like to import one then I can also provide a personal import service. :)
Title: cosworth vs rx7
Post by: asp on June 03, 2005, 06:39:51 PM
where is wick.jus askin cos theres 1 buy me,
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 06:46:58 PM
wick is in caithness in scotland i am as far north as you can go i live 18 miles from john o groats wick was taken off the vicking word for vic from when they cames over an concered orkney shetland and the very top of the highlands i bet you will sleep tonight knowing that
Title: cosworth vs rx7
Post by: RobbieRX-7 on June 03, 2005, 07:25:19 PM
i would seriously NOT BOTHER doing the cossie engine conversion..RX-7`s should live with the rotary for the 50/50 weight distribution. ive seen in person ,a slightly modded rx7 with blown engine going for £2600. if you add the price of a DIY rebuild (minimum £800 you can buy a kit from usa for about £600) then you basically have a new car on your drive. Then you could spend the rest on power or body mods to make it unique to yourself.

i worked it out if you buy this kit from usa..with all required gaskits and even the guidance videos the grand total is £750..BUT that is providing your engine needs no major replacement parts (rotor housings,rotors etc..)
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 07:33:37 PM
i am starting to lean that way where do you see cars for that money that would be exellent but will cost me about 500 pound and a few days of work to get the car up here
Title: cosworth vs rx7
Post by: RobbieRX-7 on June 03, 2005, 07:45:34 PM
my mate saw that car i mentioned in the autotrader..(ive even got my mates wanting a rex now!) it was breakerlink i think..we went over to see it and it started on 1 rotor, was lowered with coilovers and a few other mods (nothing drastic)

as one of the mrc members said..if you think you can tackle it then buy 1 with a blown engine..


here is where i got the prices for the rebuild kit..ive hearrd these are real good quality kits..

http://www.rotaryaviation.com/overhaul_kits.htm
Title: cosworth vs rx7
Post by: Gerry M on June 03, 2005, 08:19:16 PM
QuoteOriginally posted by jazraymcbeath
wick is in caithness in scotland i am as far north as you can go i live 18 miles from john o groats wick was taken off the vicking word for vic from when they cames over an concered orkney shetland and the very top of the highlands i bet you will sleep tonight knowing that


dont buy a rex if you live in wick!!, i\'m in thurso & wish to remain the only one in caithness!!. but seriously if you want a run in one i can sort that out but unfortunately am offshore for the next 2 weeks.
Title: cosworth vs rx7
Post by: Gerry M on June 03, 2005, 08:43:06 PM
& you\'ll prob need to go to thurso for all your petrol as i dont think you can get super ul in wick?? The only probs i find up here with a rex is the roads arent really made for jap spec suspension, super ul is only thurso & inverness as far as i know & i dont think theres a garage in caithness would touch it for maintenance. but if your a mechanic its nae probs, I\'ve done all the basic servicing on mine so far.

On the good side i\'ve found mazda in inverness to be helpful, you car get oil filter etc locally, you do get asked all the time about it as its unique up here, theres nothing looks like it, the supras, evo\'s, subarus etc are all too scared to come near you as they dont have a clue what it is.
Title: cosworth vs rx7
Post by: jazraymcbeath on June 03, 2005, 08:51:18 PM
what about the brigade of saxos and 106\'s lol
there is always a race here haha
anyway pop in when you get on shore and will get the crack and i will speak nice to my girl freind to give you a shot of the type r
Title: cosworth vs rx7
Post by: Gerry M on June 03, 2005, 09:00:46 PM
they just point & stare!!
Title: cosworth vs rx7
Post by: stu0x on June 04, 2005, 12:48:09 AM
This is probably predictably biased, but imo people who own RX7s have them because they love RX7s... more than any other car. Because it\'s so fundamentally different to every other production car, and because there are a fair few compromises to owning one, it\'s a totally irrational purchase decision. People don\'t tend to go "hmm, I want a car that can do x, y, and z, and my budget is £x..." and then work out that an RX7 is their best purchase. They buy them because to them it is just \'the car\' they want. That\'s how it worked for me anyway. Ask an RX7 owner to explain why he\'s got one and he\'ll probably just look blankly for a few seconds, then go "it\'s an RX7 mate..." :)
Title: cosworth vs rx7
Post by: gsb876 on June 04, 2005, 12:58:59 AM
Usually people buy rx7\'s to be different and the rare factor, not very often you travel somewhere and bump into rx7\'s :(

In the year and a bit i have owned mine i think apart from shows i have only ever seen 4 rx7\'s on the road :eek:
Title: cosworth vs rx7
Post by: gja7 on June 04, 2005, 01:05:46 AM
ALRITE M8 !

COULD BE  FATE HERE - I AM ONLY DOWN IN INVERNESS AND
I HAVE AN 1993 WHITE RX7 TWIN TURBO WITH A BLOWN ENGINE WHICH I AM SELLING , I WAS REALLY REALLY HOPING TO GET IT ON THE ROAD MYSELF BUT IT HAS SAT FOR A FEW MONTHS NOW AND WITH THE CLOSEST RX7 SPECIALIST BEING IN ENGLAND IT IS VERY HARD TO GET ANYONE TO HAVE A LOOK AT IT AND IF I WANTED IT REBUILT I WOULD HAVE TO TRAILER IT DOWN AND TAKE DAYS OFF WORK AND I CANNOT BE BOTHERED WITH THE HASSLE.

I JUST PUT IT ON EBAY YESTERDAY . DO YOU GO ON EBAY ?  IF YOU DO THE ITEM NUMBER IS : 4554195052

IT HAS NEVER BEEN REGISTERED SINCE IT HAS CAME INTO THE UK WHICH ISNT A PROBLEM BECAUSE ALL YOU HAVE TO DO IS REBUILD IT GET IT MOT\'D AND REGISTER IT WITH DVLA FOR PENNIES WHO WILL THEN GIVE YOU A NUMBER PLATE . EASY AS THAT.  I HAVE ALL THE DOCUMENTS AT MY HOME AND I HAVE PAID ALL THE CHARGES INCLUDING SHIPPING ETC.

IT HAS HAD A LOT OF MONEY SPENT ON IT HAS UPRATED EVERYTHING. BODYKIT , ALLOYS , DUMP VALVES , SUSPENSION , QUICK SHIFT , STEERING WHEEL ,INDUCTION KIT ,                          EXHAUST  ( NEEDS NEW CAT ) , APEXI STUFF ETC AND RUNS ABOUT 300BHP.

IT IS SITTING AT MY PARENTS HOUSE IF YOU WANTED TO COME DOWN FOR A LOOK BUT  IT IS UP FOR SALE NOW SO WITHOUT PRESSURING YOU IT WOULD HAVE TO BE SOON . I WOULD LET YOU HAVE IT FOR  Â£3500 CASH BUT I CANNOT GO ANY LOWER AS IT COST ME ALOT MORE BUT I AM WILLING TO CUT MY LOSSES. IF I DONT GET THAT FOR IT THOUGH I WILL JUST GET IT REBUILT MYSELF BUT I THOUGHT I WOULD TRY AND SELL IT THE WAY IT IS FIRST.                                                                    

LET ME KNOW WHAT YOU THINK - GRAEME !                  :bandit
Title: cosworth vs rx7
Post by: scud on June 14, 2005, 11:28:02 PM
gja7 is this the white rex on e-bay ?
Title: cosworth vs rx7
Post by: rxv8 on June 14, 2005, 11:41:08 PM
i think it is mate...
Title: cosworth vs rx7
Post by: jazraymcbeath on June 15, 2005, 12:24:20 AM
yes thats him
Title: White RX7
Post by: gja7 on June 15, 2005, 01:56:42 AM
:3gears-rh

 Yep that is my white rx7 . Let me know if you know of anyone who is interested in it . Cheers !!!
Title: cosworth vs rx7
Post by: jazraymcbeath on June 15, 2005, 12:10:15 PM
sorry to hear you did you not get anyone serious about the car as you said there was a lot of interest in the car but thats about all there is on ebay interest but we are that far north it is even harder to sell
as discussed when i sell the cossie i am very interested but not at 3.5 for a car that is not registered and needs a rebuild was going to contact you but deleted all my old emails my mistake sorry

cheers
jaz
Title: cosworth vs rx7
Post by: jazraymcbeath on June 15, 2005, 12:16:38 PM
could gerry m please contact me

cheers
jaz
Title: cosworth vs rx7
Post by: gja7 on June 21, 2005, 02:32:43 AM
NO PROBLEM JAZ .I HAVE A GUY COMING TO VIEW IT FROM READING AND ANOTHER FROM EDINBURGH THIS WEEK AND NEXT WEEK BUT IN THE MEANTIME  IF YOU SELL YOUR COSSIE BEFORE I SELL THE REX GIVE ME A BELL ON  graemeallison@msn.com AND WE CAN DISCUSS A DEAL BUT THERE IS A PRICE I WILL NOT GO BELOW  !!!