Hi All,
This is my sirion gtvi from Melbourne.
Bought it start of this year to be a cheap track car, it’s now survived 3 track days with the nugget nationals series. They require car to be under $3000 purchase cost, 1.5l max capacity and no turbos hybrids or rotaries are allowed. Most nugget cars are 1.5l swifts, echos or Honda jazz probably as their easy to mod and have good power to weight ratio.
Well so does the gtvi, so when it came up for sale for under 3k I thought why not.
I’ve gone from doing the first event bone stock to now having, 15 inch (not sure if real) enkeiis with hankook rs4 tyres, slotted rotors, pads and hi temp fluid, rear drums are still onboard. Brakes are not the best but they haven’t overheated yet. I’ve also installed the Malaysian headers and bc coilovers.
Last event we ran 1:13 at broadford. 1st time out on stock everything was 1:18 so 5 seconds faster. The lead guys were 1:11 so maybe we can keep improving.
Thanks for accepting me and for all the valuable info you all contribute.
Welcome. Would be great to see some images, esp in comp. I’m sure you can close the gap further. Get onto the spring rates and some testing to get rid of any understeer. Stiffen up the rear and soften the front till it is lifting inner rear wheels. You’ll find at that point you are getting the best front grip. Copen front brakes will fit and if you can find some Appluase rear rotors and calipers the conversion onto yours is not too hard. I’d be keen myself to get the flywheel out and lighten it up as much as possible if the rules allow, it’ll transform the engine. All the best.
Gormsby
Good choice in vehicle, they can be made to be quite quick.
If lower final drive or gear ratio changes are permitted - it will make a big difference. The gearing is long and so there is a lot of improveing in acceleration using various daihatsu final drives depending on what you’re after.
Thanks Gents.
Agree The bc coils are way too hard up front. I’m not sure how much softer go on the front but it felt gripppier on lowered king springs with rubber blocks jammed on the rear, (got that idea from you Gormsby). That had it rotating nicely. Any steering help is good as the steering ain’t the quickest. It’s more stable now but I guess I’ll find out if it’s faster in a couple of weeks when we go back to Winton raceway as it will be the only change since last visit there.
I’ve contacted BC about softer front springs but no help as yet.
I haven’t figured out photos yet but it looks like ur twin TPG. Even has the paint fade in similar spots.
Nugget rules don’t allow flywheel lightening unfortunately so I’ll leave standard for now. No LSD allowed either. I do have a set of 13” wheels to try out instead of changing final drive for now, but haven’t put new tyres on em yet. I’ll probably fit 185/60/13 nankang ns2rs as theyres not a huge variety of choices for 13s. Or maybe 175/50/13 for an even bigger difference.
Ist photo is on old setup. Lots of fun backing it into the hairpin. Maybe not the fastest way round.
Photo 2 is last track day with its new bc coils on.
I tried hard but could not get that rear wheel up, lol.
It really is a twin!!
If you could get the and were allowed to run them Nangkang do the AR1 in a 185/60/13. They are a huge step up from the NS2rs. The RS4 should be a good wet weather tire as they don’t need to come up to temp. I’d guess std front rate would be in the 150-180ft/lb range. A BC coilover strut will take any coilover in the same diameter and length. If the rate is printed on them just measure the free length and diameter and order the rate you think you need.
Concerning flywheels. I’d keep it in mind that there might be something lighter that fits, as in not having to machine it but from a Daihatsu. I don’t remember if the EJ and K3VE are the same flywheel. If they were you could use a L200 flywheel which should be lighter but not machined.
Quicker steering. AE86 or AW11 can be made to fit. The last one I did I machined the rack to fit the Dai. If I did it again I’d mod he K frame to fit the Toyota rack. Stock ones will give you about 2.5 turns lock to lock. I went quicker again with a Quaife quick rack and pinion and was close to 1.5 turns. You have to do a hybrid steering knuckle using half of a Dai knuckle and half a Toyota pressing the universal out and back together.
Have you calculated the drive ratio change from the small overall diameter rims going from 15’s (with presumable 195/50’s) to the two different 13" options? I wonder how big a different it would make compared to any sacrifice in overall grip…
If brakes are ‘free’ or brake changes permitted within the brand - then the larger copen brakes will be a good upgrade. They definitely shortened my braking distances.
Ar1s are out unfortunately. Tyres must be tread wear rating of 140 or higher.
But t seems i misread the regs, i can machine but not replace the flywheel and i can change final drive, so my 15s can stay if i do those. More gears must be a bit faster, i can currently do Broadford all 3rd gear. Slowest point 80k fastest 145
Brakes are ok to mod so I’ll start looking for applause rears and copen fronts.
Thanks for the ideas.
All I’ve done is used a tyre size app
185/60/13 is a 4.6% drop in circumference
If that equate to 100km is now 95kmh then it’s probably not enough is it?
The skinnier 175/50/13 is 14% smaller than my 15s.
So with them, I’d guess 3rd gear would run from 85 to 125 instead of 105 to 145. Much better gearing but maybe too much 1 wheel peel outta the turns.
I’d have to fit the street 180 tw ns2rs too. Theres race 120. Tw but our regs say 140 or above.
That was similar to my experience the first time out:
The long gearing of the Sirion meant only needing gears 2 and 3. The back straight or ‘kink’ at Mallala is the highest speed section and I entered the braking zone around 145km/h in the very top of 3rd.
At Mallala specifically, due to the long gearing of the sirion, all I originally needed was 2nd and 3rd. The lower Final drive has brought 4th in to play on the track, with the acceleration out of 2nd quite astonishing for a small engine (aided by LSD too).
Depending on the exact nature of the track, either the smaller OD wheels or a lower final drive should bring the ability to choose a better gear for the corner. There is the copen FD and a few other Diahatsu model FD’s that fit and are lower than the factory GTI but not as low as the Copen. In an ideal would there would be some calculation to match the FD to the track you race at to optimise the gear spacing.
Although, I doubt 13" wheels would fit over the copen brakes.
There was a good post by Patrick Hart on my thread about going to an even smaller 12" wheel with wider tyres and actually smaller brakes. Using the mechanical grip of the wide tyre and having ‘just enough’ brake to work whilst keeping the weight low, and the even small wheel improve the gearing.
Ultimately, I didn’t follow that, and went with 15" rims and copen brakes and actually changing the gearing via the final drive and not tyre diameter.
I have not tried the Nangkang CRS semi slick (200tw) but I hear they are better than the NS2r and not a real 200tw. They do a 195/50/15
Copen’s won’t fit 13" as you guessed and don’t fit many of the 14" I tried.
You’re right Mr g as always.
I’ve fitted a harness today to the standard seat.
Massive improvement. Fitted using eyebolts and cam buckles so it can easily be taken off. I also bought another seat from the wreckers for $60 but I may only cut the foam out of the bottom at this stage to get the seating position a bit lower
It’s a shame someone rear ended the gtvi at jolly’s
Ringwood. Apart from the damage to the hatch, there’s not a mark on it I’ve never seen one so nice, I’m tempted to grab the front end and 1/4s off it.
Ive also got 2kg front coils on the way. Mine are 4kg and do not budge if you push down on the car.
My rears are 3kg and being tapered are not so easy to replace. I may just put the rubber buffers back in for now I did have a small rear sway bar onboard that I grabbed off an early model 1.0 sirion. I didn’t seem to do much when I installed it but I’m now noticing more lean and twitchyness in the rear without it.
for a four point harness make really sure the lap belt is really tight before doing the shoulder straps (sash), if not you aren’t being held properly and as well as not having good retention of yourself in the seat you will submarine under the lap.
If you leave the rubbers out of the back springs it will give you more rate which the rear could prob do with.
Looking good.