Job done.
Tried the Mazda injectors but they made it run way too rich. Car still runs the factory ECU so no way of adjusting the fueling. So put the std Dai injectors back in.
Runs very well. Idle not too lumpy. Needs a dyno tune to get the tune spot on. Pretty sure there’s a few more HP gained there. It certainly feels like it has more pull and it revs out so much better too.
Here’s a copy of the cam specs. Also a pic of the exhaust porting. I forgot to take 1 of the intake before putting it together sorry lol.
Yeah PK is a smaller outfit that has built many top class race and rally car motors etc.
The requirements we gave him was it had to idle and rev limit was 7K max
Going to get dyno tuned soon so hope to see good gains
Been looking at a shorter trumpet design (40mm shorter with more of a taper) - no worries shortening these, but trying to get the filter to fit is going to be a challenge.
Not much! I am sure I will find a way around it though. 40mm should move the power up 500 to 600 rpm and be about perfect for road use, motorkhana’s and the odd track day.
Yes, its nice o see it layed out on a graph, makes me wonder if ive been tackling the problem the wrong way with mine, trying to achieve resonance in the intake pipe. This is more or less what ive been using to calculate the length of the intake pipe, but ive just realised in an itb setup there will be one pulse for every 2 crankshft rotations, whereas a normal intake manifold (4cyl) will have 2 pulses in the plenum for every one rotation. Just thinking out loud here but i think its time to go back to the drawing board for me…
As mentioned previously, my car seemed to understeer a lot at the last autox event I entered. I must confess that engine mods generally interest me far more than suspension, but I am now at a point where I should look into it further.
So I studied videos of my laps. It has been interesting to compare it with another entry (in a Peugeot 205) who set the quickest overall time. The pic below of the same corner (the 205 on the left) shows how body roll my car has compared to the Pug. I had been contemplating slightly stiffer (15% by my calcs) OEM GTti front springs, as I suspect my OEM fronts are shagged after 200k. And perhaps upgrading the rear anti roll bar from 16mm to 20mm.
I did find an old doc with spring rates from Daihatsu NZ’s rally GTti (looks like from 88). These could be a good place to start if I was to look into custom spring rates and dampers. Not sure who does this type of work though, and how much it costs.
I still want to have car that drives nicely on the road, but would like to improve the current setup. Any sensible suggestions are welcome.
Stiff front will only make it understeer more. Stiffer rear is the way to go. Put some chocks between the coils on the rear and test. I make up some blocks to go between the coils, put some holes in for big zip ties to hold in place and do a short test.
The rates for the rally car would be for dirt and have to do with long travel and stopping bottoming out. I have a mate/old boss that has been works driver and international navigator and is also a major race tire distributor whom runs an ex works Daihatsu with his son-in-law on dirt and asphalt - prompt me to ask some questions of him.
If you stiffen the front it is only going to transfer more grip to the rear. Add the sway bar when you get the rear rate correct and make sure it is the smallest bar you can get away with, it should have three or four adjustment settings on the blades (as in holes to change the stays). This way you have a way to tune the car on track days by using the holes or even omitting the bar (if it is a big bar then disconcerting will have too dramatic of an effect).
Stiffening the front not only makes for understeer but if you have an open diff you will have a lot more wheel spin. Do you have an lsd?
Play with one end at a time or else you will confuse yourself. Again I say stiffen the rear first with chocks before buying springs front or rear.
Based on your pics I’d say the 205 has less steering angle and is either taking a way diff line or is only just turning in and weight has not transferred. Pic is not good comparison.
Thanks for replying Mr G - as always I appreciate your input.
I like to gather a bit of knowledge before making decisions as decision by guesswork isn’t my favourite process.
One of my current theories is that the stock front springs are soft enough that the front outside is bottoming out on the bump stop. Once this happens its a bit of a guess as to what the effective spring rate is. I plan to mount a go pro under the car and do some driving. If its bottoming out then getting better front springs would seem a good thing. Then I can move on to having a look at stiffening the rear as you suggest.
My car runs an open diff - and yes it wheel spins quite well, pedal down in 2nd is all it takes most times. Would love an LSD of some type, but that’s a project for another time.
Just uploaded some video - again any thoughts appreciated:
Front springs are original springs on stock Monroe shocks. Rear springs are Gtti springs (replaced 2 years ago) on stock KYB shocks.
The original rears (that I replaced 2 years ago) were ridiculously soft, it used to amuse my mates when I would step on it, as it used to looked like a 1000hp awd drag car.
The front has the factory sway bar 22mm diameter, the rear (again factory) sway bay 16mm diameter. Tyres are 195/50R15 Adrenalin Re003’s. No adjustment is available.
Monroe and stock! It would be a dog. More spring rate will make things worse. The struts and shocks are not able to control spring oscillation as it is and more rate will be beyond their capability. You said it is possibly bottoming in the front, I doubt the front have any bump control. As a minimum I’d put some Koni red in the front or pref external adjust Koni sport (yellow) in the front. Even pumping the oil out of what you have and going up to ten or fifteen weight would be a step in the right direction. What is in there will be like 5wt or less (it will be like water and could be cooked too).
Sway bar, you want something like this on the rear for quick adjsutment
Some ends can be forged and drilled and some can have an angle grinder make a 6mm slot up the middle and ends welded on.
