The Mid Night Club Wangan Run Touge Monster FD RX-7 RZ!

The Mid Night Club Wangan Run Touge Monster FD RX-7 RZ!

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declasm

Original Poster:

426 posts

196 months

Wednesday 6th February 2019
quotequote all
I think it's about time we talked power numbers.


Here's the car as it stands today, still not shiny or clean and riding high on those oh so comfortable BC Racing coilovers.

A few weeks back I found a fascinating video describing a process whereby ECU datalogging can be used to estimate the power a car puts down on the road given some precise measurements for weight, wheel radius and gearing. A brilliant developer had wrapped up the whole set of equations into an application that pumps our dyno graphs as a result.

The video is here on the CarPassionChannel on youtube: https://www.youtube.com/watch?v=Sz7NBbFBQ9Y

The application is called Virtual Dyno and I'm surprised it doesn't get more exposure as it takes all the hassle out of this process. You can download the application here: https://barnhill.bitbucket.io/

If you're interested in testimonials and validation of Virtual Dyno there are some great examples here: https://innovativetuning.wordpress.com/our-experim...

I checked the compatibility of Virtual Dyno and found that it was already compatible with the logs produced by the FC-Edit application I use on a laptop connected to my APEXi Power FC ECU so I was good to go.

So to today, finally the ground was dry and it wasn't too cold so I decided that a Wednesday lunchtime might afford me some opportunities for some full throttle pulls at my local 'empty private test track'.

I found a piece of 'track' that was clear, straight, well-sighted and not on a slope and made several 3rd gear pulls from 40mph to 90mph, trying to stay at full throttle the entire time. Maybe it's because I haven't driven the car in a long time or maybe because the new spark plugs have cleared a bit of ignition break-up in the high rev range but today the car pulled cleaner, harder and more intensely than ever before all the way up to about 7500rpm, the torque was so consistent across the whole powerband - I could *feel* that it was. These full throttle pulls were no joke, I think I made 3 'good' passes where I didn't lift early or whatever but every time I couldn't tear my eyes from the road or look at any instruments but I had been logging the whole time. I actually couldn't wait to get home and see what Virtual Dyno made of my logs.

As I said before, Virtual Dyno is compatible with my log files and it even had a ready made profile for my car, I just had to slightly adjust the weight, wheel radius and final drive to match my exact model and mods which took all of about a minute.

I had to trim my log to include only the full throttle pull (otherwise all the other parts of the drive overlap the graph) but that was simple in notepad++. Generally Virtual Dyno also measures throttle opening and defaults to graphing only those sections but either I was too chicken to keep my foot in the whole time (most likely) or my TPS logging isn't perfect.

So here's my curve:


The curve gives a peak power figure of 374rwhp as if measured on a DynoJet dyno. Based on the assumption of a 15% drivetrain loss this give a bragging figure of 430bhp.

The torque curve and boost curve (ignore units - boost peaks at 14psi/0.965bar by converting the logged figures) are fascinating to me. Boost reaches 7psi by about 4000rpm and maxes at 14psi by 5000rpm and then stays rock solid all the way up to 7500rpm. Torque (that I can confirm because of the feel) was very flat and consistent in that range too. Max torque was 300lbft at the wheels and likely about 340lbft at the crank.

Other figures of interest are the AFR which was about 11.4:1 in the low rev range, reaching about 10.5:1 at 7500rpm. If you're not used to rotaries this might seem ridiculously rich but this is just how they like it (the 11:1 at idle might make you cough tho...). Water temp didn't budge from 75C and intake temps didn't budge from 21C - the V-mount setup does a tremendous job cooling the 13B.

Overall I'm very pleased. I've put in a good amount of time learning how to map and tune the car so having a respectable number to go with it is a great badge. I can honestly say the car is absolutely running the best it's ever been, it's a big step away from when I bought it.

I currently have an HKS 'silent hi-power' cat-back exhaust sat in the garage waiting to go on the car, hopefully allowing the volume to drop several more dB before my next track outing at the Castle Combe Spring Action Day at the end of March. I'm still waiting for my rear discs to come in from Japan and still contemplating spending 600 quid on new discs for the front. Once those are done I'll go to town on cleaning the car up and making it a little shinier and then try to enjoy it more than last year.

declasm

Original Poster:

426 posts

196 months

Saturday 2nd March 2019
quotequote all
Quick update!

Car is on the road, got a three day trip to Surrey/Hampshire next week so that will give the car a little workout.

So I cleaned it and went to my normal spot for some pics:















Now I have some final parts in for my 2019 season upgrades and maintenance:



This is the HKS Silent HiPower cat-back exhaust section. It should be pretty quiet in the greater scheme of modified FDs. I also have an TGS Tuning silenced mid-pipe on it's way - should be here Monday!



Other parts are brakes. I bit the bullet and bought some replacement front rotors from Sumo Power. They are Girodisc grooved/vented and are a direct replacement for my Brembo rotors:



And finally after ordering in October I have some rear discs too! These are the Dixcel 314mm RZ fitment discs that don't seem to be available anywhere. I got them through Essex Rotary who couldn't apologise enough for the delay as their Japanese supplier went very quiet for a long time.



I might be going to the Haynes meet tomorrow - might see some of you there!


declasm

Original Poster:

426 posts

196 months

Tuesday 2nd April 2019
quotequote all
Had a couple of busy car days last week, installing the previously mentioned exhaust and brakes



2-piece brake rotors were something I'd not dealt with before but the old ones came apart easily and the new rotors were a direct fit as promised.



Driver's side front was a right pig! We couldn't get one of the new pads to sit right and the first time we got it in it completely jammed. After that we filed down the edges of the pad and tried to clean the caliper as much as possible but it still took hours longer than it should have to get it to fit right.



Rears were pretty straightforward in comparison, here's a before and after:



I didn't get many pics of the exhaust, it did take me a few goes to line it all up without leaks working under the car in the garage. Here's the system before it went on the car next to the one I had just taken off:



Annoyingly the bung for the wideband o2 sensor on the new exhaust is in exactly the wrong place and the installing the sensor there would interfere with my gearbox brace. I need to rethink the position or use the bung on the downpipe next to the turbo where the stock sensor goes at the risk of frying my sensor or at least shortening its life.

With the work done I got the car cleanish and prepped a bit for Spring Action Day at Castle Combe



Then it was up early on Saturday morning to convoy there in the fog (this might be the only road rolling shot I have of the car?)



The first couple of hours of the show were a blur trying to work out where I needed to go for sound testing (yes - the new exhaust easily passed Combe's noise test!), drivers' briefing and the queue for the track but eventually I got on there - my first time on Castle Combe.





Obviously I was a little apprehensive - lots of new stuff since I last went on track - new front tyres, new coilovers, new brakes all round. I forgot to set my dampers to 'stiff' before rolling out and the new BC Racing coils felt totally different from my old Quantums - loads of grip there but soft springs meant a lot of suspension travel. The big disappointment was the brakes - only having had the motorway drive up to bed them in a bit they weren't ready for the track and didn't have the bite I needed to feel confident and because they weren't bedded fully they faded pretty quickly. The session was prematurely halted after about 10 mins when someone spun off so I took that as my opportunity to leave before I ran out of brakes. I'm hoping the short track session will have sped up the bedding in process and the bite will return soon. Thankfully the brake judder I had at Llandow last year has disappeared completely with the new setup. I consider it overall to be a good track session since I went out, came in and didn't break myself or the car!

After that I enjoyed a lovely day in the sun looking at all the show cars and watching the cars on track. I left a little earlier than the rest of my club but convoyed with a Mk4 Supra that I met on the M5, all the way back to Exeter! We had a couple of spirited pulls and this exposed an aspect of my tuning I hadn't considered yet - On the motorway I was doing pulls in 4th gear and I saw my boost rise to 1.13bar or 16psi, during my tuning pulls in 3rd the engine load and wastegate only boosted to 0.96bar. The car pulled *hard* at 16psi (probably 450bhp since I was making 430bhp at 14psi) but I think I might want to dial that out with my boost control settings for the sake of the engine.












declasm

Original Poster:

426 posts

196 months

Monday 15th April 2019
quotequote all
A couple more track shots I was sent from Castle Combe.



declasm

Original Poster:

426 posts

196 months

Friday 27th September 2019
quotequote all
So the car is looking alright and running alright. I've got the BC Racing dampers setup to feel really good for road driving, everything should be great but I'm finding more and more that I have so little time to drive the car. This is very sad. Part of the problem is that with only two seats I can't take the family out in it on weekends and my weekend activities invariably revolve around the family! To this end I'm looking to sell now and move onto an E9X 335i and tune that for power. I've had some interest in the car and for peace of mind for me and the prospective new owners I sought to get a compression test done. Mazda wanted to charge me £170 for what is a 10 minute job with their special tester but I couldn't schedule that in so I did it the hard way at home - here's a little video:

https://youtu.be/U1Cuf71caac

And the results:



And a reference diagram for engine health:











And another video with some boosting for good measure

https://youtu.be/ivJMXVQLOqU

declasm

Original Poster:

426 posts

196 months

Monday 30th September 2019
quotequote all
I went along to the new cars and coffee style Re:Fuel meet at the Froginwell Vineyard about 15 mins away from me on Sunday, a friend of mine with another black Mazda (mk3 MX-5) managed to arrive at the same time so we could park up for some pics







Good meet and I got did some testing of an old GoPro that I recently got my hands on too:

https://youtu.be/lH0qWNWY2Wg

declasm

Original Poster:

426 posts

196 months

Tuesday 11th February 2020
quotequote all
Time to wrap this thread up!

Back in November I took the car over to Smeatharpe airfield for some more drag racing. I was really hoping 1. that it was going to be dry and 2. that I would be able to get the car into the 12s. Fail on both counts, it was wet and miserable and the track was soaked and slippery, quite intense and a challenge to keep my foot down for fear of aquaplaning off the strip. The car didn't cut a 12 either, really no chance in the conditions. In the end I got a 13.79 @ 111MPH with a best 60' of 2.5. Pretty much means that with dry conditions and 2.0 or better 60' the car would get mid 12s but I wasn't going to see that.

Here's a quick video of one of my runs

https://www.youtube.com/watch?v=izAPJdLv1lk

The only other worthwhile driving in the back end 2019 was a good run up to Warwick castle and back in December but on that trip I found that I was experiencing a new crunch shifting into 2nd gear. ffs.

With the MOT due early January I decided to get a bit more serious about selling the car, having done all the mods and having done all the events I wanted to do. I decided to sell it as is, mentioning the new gearbox fault and the short MOT and try my luck.

Final spec (as per the ad) went like this:

1997 Mazda RX-7 RZ Special Edition

PZ Black
45K Miles

RZ Special Edition features:
Original Recaro RZ Carbon Kevlar seats
RZ alloy passenger footrest
RZ rear bins not seats
Twin Front Mounted Oil Coolers

Engine and performance modifications:
Rebuilt in Japan prior to export in 2015
Compression (at 35K miles) F 7.5, 7.3, 7.3 R 7.7, 7.5, 7.3
Compression (at 44K miles) F 7.4, 7.1, 6.7 R 7.2, 7.4, 7.4
A'PEXi Power FC ECU, Commander, boost controller and upgraded 3 Bar MAP sensor
HKS T04R single turbo conversion
HKS Turbo Timer
HKS Coil Leads
HKS Twin Spark ignition amplifier
Knight Sports V-mount radiator / intercooler
Knight Sports throttle body
Greddy Type-C wastegate
HPI Induction Kit
AEM 30-4110 Wideband AFR gauge with Bosch LSU 4.9 sensor
Denso Iridium Racing IRE01-31 spark plugs
2-way Kaaz LSD
Competition paddle race clutch

Fuel System:
Uprated fuel pump wiring
SARD Fuel Pressure Regulator
850cc primary injectors
1700cc Injector Dynamics ID1700x secondary injectors
DM Motorsport secondary fuel rail
Modified primary rail

Exhaust:
Trust exhaust manifold
HKS downpipe
TG Motorsport silenced mid pipe
HKS Hi-Power Silent cat back
Screamer pipe
This exhaust setup has no problems with track day noise regulations

Chassis and suspension:
Cusco Front Strut Brace
BC Racing BR Custom Adjustable Coilovers with F 8Kg R 6Kg springs and rubber top mounts
Transmission chassis brace

Brakes, Wheels and Tyres:
H&R 25mm hubcentric spacers all round
Brembo GT 332x32 2-Piece 4 Piston Black Front Big Brake Kit
Girodisc 332mm grooved / vented front rotors
Dixcel 314mm rear discs (larger RZ / Spirit R specific size)
Rays Mazdaspeed MS-01S Forged Monoblock 17” wheels, F 8.5J R 9.5J
Rear 255mm Continental ContiSportContact 5 tyres
Front 235mm Goodyear Eagle F1 tyres

Interior
Motamec suede steering wheel
Boost gauge
APEXi commander
Turbo timer
Knight Sports WT Controller (controls the rad fan)
Single-din bluetooth / mp3 headunit
Speedo and mileage converted to miles / MPH

Exterior
ARC Magic GT Rear Wing
Knight Sports vented bonnet
Knight Sports vented headlight cover
Knight Sports side skirts
Knight Sports bolt-on wide arch kit
“Extreme Dimensions” branded C-West rep bumper
Rear fog light

Extras
Quantum Racing "RE Spec Coilover kit" with pillow ball top mounts (best for track only)
2 spare (exceptionally loud) exhausts (mid pipe and cat-back)
FC-Datalogit APEXi ECU interface cable


So last weekend I sold the car, for asking price, to an enthusiast who drove several thousand miles from Prague! Apparently it was 24hrs each way. My car is now sat in his garage, next to his S13







Reflecting on the sale, I got a good price for what I had and now I have a sense of relief, so I know I made the right choice to sell. This was my 3rd FD RX-7, with my first 2 I had unfinished business but with this one I ticked all the boxes, did the majority of the work myself and learnt how to map a rotary. I did mods to improve reliability and performance but also made it a road car with the suspension and exhaust mods. It was never a perfect road car, always too extreme for that and that meant I couldn't use it maybe as much as I could have. Despite all the horror stories you hear, a 400bhp RX-7 isn't a ticking time-bomb, it was probably one of the most reliable cars I've had, never failing to start, even after sometimes spending weeks in the garage. Now on to the next thing!

declasm

Original Poster:

426 posts

196 months

Wednesday 12th February 2020
quotequote all
Rod200SX said:
Awesome car and I'm glad you had a good time with it. A few friends that have got/had RX7s in various shapes have all been generally reliable.

Am I right in saying I saw you posting on a facebook group looking for a new car? Maybe a BMW one, I've got so many pages I follow hehe
Yep that's me, looking for an e93 335i - are you selling one? wink

declasm

Original Poster:

426 posts

196 months

Friday 14th February 2020
quotequote all
Rod200SX said:
Alas, no! I wanted an E93 but couldn't find a good one in budget at the time so ended up with a manual E92. The N54 is an incredible engine despite their issues!
How do you find the manual? My current daily is an e91 330d auto with flappy paddles and it's perfect but I'm going to look at a manual e93 on Sunday as a weekend car to replace the RX-7