SR20 Time Attack MX5

PapaSmurf · Postby **PapaSmurf** » Sat Mar 22, 2014 12:48 am

Hi Guys,

For those of you who are into something a little different. A 15 month project that's getting closer to the end...

- 1990 NA MX5
- NB Fenders and Headlights
- Nissan SR20 Engine (PLR Performance)
- Engine Stroked to 2.2L with HKS Stroker Kit
- Cage, Splitter, Diffuser, Canards, Flares, Wing Mounts (Fabrication 81)
- Tune, ECU, Dry Sump, Engine Install (STZ Automotive)
- Single Element Wing (Custom copy of Nemo wing by Cawthorne Composites)
- Inconnell Exhaust (CES Racing Systems)
- Garrett GTX30 Turbo
- E85 Fuel
- 2200cc injectors
- Dry Sump
- Nissan Skyline RB25 Gearbox
- Custom Clutch
- RX7 FC Diff with KAAZ 1.5 LSD
- Haltech ECU and digital display
- Enkei RPF1 Rims (17 x 9.5 all round)
- 255 Wide Semi Slicks all round
- MCA Coilovers (Reds)
- RX8 Rotors (Front)
- RX7 Rotors (Rear)
- Wilwood Calipers Front
- RX7 Calipers Rear
- Datsun 260Z Extra Wide Fender Flares
- Custom Chassis Bracing
- APR Mirrors
- Carbon Trunk
- Carbon Doors (To Come)
- Dyno Estimate 400+ whp at 20 psi (Still running engine in)

Might be at the national MX5 meet at Lakeside Park in a few weeks. No fast laps though as still running in engine at 200whp and dialing in aero and coilovers.

Dean

Dweezle · Postby **Dweezle** » Sat Mar 22, 2014 5:45 am

This I love!!

Good luck to you.
Might we see you at WTAC??

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track_addict · Postby **track_addict** » Sat Mar 22, 2014 7:24 am

This is awesome. 100% nothing but pure awesome. How hard was it getting an SR in there? Will be very interesting to see its times once run/dialed in.

PapaSmurf · Postby **PapaSmurf** » Sat Mar 22, 2014 7:41 am

Thanks Track Addict. It was running low 57's at Lakeside and flat 56's on the Sprint Circuit at QR with 300whp on the old engine and old aero, so I'm hoping for at least 1+ seconds less with the newer and bigger aero. Will take a few months to dial in the balance again.

speed freak · Postby **speed freak** » Sat Mar 22, 2014 5:31 pm

Nice work mate and welcome to the forum.

I saw this at my last track meet at QR I think either at the start of the year or the last one last year. (street sprints)

Looks really good. Should put in some fast lap times when the engine is run in.

PapaSmurf · Postby **PapaSmurf** » Sat Mar 22, 2014 7:52 pm

Thanks guys. The plan is to do Jap Nats and then world Time attack this year, but mainly as a test/feeler year. Will still be sorting out balance and aero around Jap Nats time and haven't dríven Eastern Creek yet so will be taking it relatively easy.

Just got the MCA coilovers installed today. If you want the best coilovers in the business, go and see Josh Coote at MCA Suspension. These guys do most of the top time attack cars in the world and they really know their stuff. Only down side is they highlight all the other suspension problems I've now got to sort out in order for their shocks to work properly. (The car weighed in at 1060kg with a full tank of fuel (45kg). Balance is 54/46).

With regard to Track Attacks question, the SR20 fits nicely into the engine bay. The problem is getting the mounting kit and custom oil pan which is very expensive and hard to find. Dry sump is the other option.

Other major issue I've had is wheels and tyres (as you know). Going to 17 inch and wider rubber means 5 bolt pattern, custom machined hubs, custom spacers, different ball joints (It's got FC Commodore up front) and cutting out the front wheel well to prevent rubbing. And despite this, I've still got problems with rapid bearing wear and ball joints getting loose.

Happy to answer any other questions.

Postby **NitroDann** » Sat Mar 22, 2014 8:38 pm

End HP goal around 600whp? If not why not?

Why did you put on 17's and only 9.5's with narrow rubber? Class rules?

Why all of the brakes and stuff without going to hubs big enough to cope with the load?

Why do you have the same wing as nemo, budget constraints stopped you designing a wing specifically for this car?

Car looks like it was built excellently btw.

Dann

zero00 · Postby **zero00** » Sat Mar 22, 2014 9:03 pm

Look forward to seeing you at Lakeside on the 14th and understand 'running in' - I will point you past!!

Si.G · Postby **Si.G** » Sun Mar 23, 2014 12:18 am

Car looks sweet, couple of questions....

-- is the floor flat?
-- how much would you say the diffuser benefits in a laptimes (thinking of making one myself)?

PapaSmurf · Postby **PapaSmurf** » Sun Mar 23, 2014 10:33 am

Wow. Thanks for all the good questions guys.

POWER:
The car is just an evolving hobby and something to have fun with, so I'm not out break records or run ridiculous power in order to win a trophy, dyno shootout, or promote a business. I've had it for few years and it gets upgrades as I need to replace or rebuild things such as the engine. If I do eventually go down that path then I'd be looking at a sequential, VET head and 600+whp, but that's not on the cards... fun and drive ability within a reasonable budget is.

AERO:
The car is tailored to Open Class rules of world time attack so I can't run a full flat floor and there are limitations on aero dimensions. Not sure about diffuser effectiveness at this stage, so will test and check data over the coming year. The Nemo wing copy (it's narrower than Nemo's and only a single element) came about because I know the guy who built it, got a good price, and can get it trimmed if need be. A twin element Nemo wing is about $5K. If you want a custom designed one from an aero expert such as Andrew Brilliant, throw on a few grand more as well. So to answer your question... Yes, budget constraints.

RUBBER:
Yep, you're right, rubber on the rear is likely to be too narrow at 255 and the plan is to go to 18's and wider rubber, but wanted a baseline to start with and already had the 9.5 inch rims as well.

HUBS:
The custom hubs are a legacy from the original owner and are undersized. Something that will need to resolved.

As you all know, the faster and more powerful you go, the more force, strain and wear on components. That then directly translates in more expensive (or custom) components and LOTS of trial and error as there is no similar existing baseline to refer to.

sailaholic · Postby **sailaholic** » Sun Mar 23, 2014 10:45 am

There is a mob in the states that makes drop spindles and fits mr2 spider hubs for extra strength if that's any help.

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