patsmx5

iTrader: (16)

You got me worrying how much my stock 99 auto is going to hold. Will found out soon enough.

miata2fast

iTrader: (2)

No offense, but I can't think of a worse gear ratio than a 3.63 for dragstrip use with your power level. I understand the desire to have a comfortable street car, but you are leaving an awful lot on the table.

mx5psi

my friends who have experience in drag racing say the more power the taller you go for more mph as you have the power to hit limiter with shorter ratio's

and if you look at the ratio's of the jatco i needed more legs



i could be wrong i bought the 3.63's when it was manual i may go back to 3.9's depending on how it goes on the track i just spoke to my auto builder asking about the thing revving to 6,800 rpm he said some cars do it they build your converter to the cars specs there are two ways to check mph on the track and Dyno and check rpm vs wheel speed

miata2fast

iTrader: (2)

How tall of a tire?

mx5psi

225/50/15 is the tyre and so far feels like it sticks well

mx5psi

mx5psi

Ok so everything works a treat hits limiter in third at 132mph so gearing seems perfect it comes on hard on the dyno with the converter

the intresting things we tried 2 more psi got some blowout but the dyno line jumped up a silly amount so i might have to regap plugs or upgrade the ls coils thats at 27.1psi i want 28psi in the end

the fuels are pretty good there is one dip we want to clean up we also might throw some more timing in it see what happens

i want 300rwkw back

patsmx5

iTrader: (16)

343whp/460wtq for those curious.

Day-um! Am I reading that right, 625 Nm of torque?

Did you figure out if the converter is slipping?

mx5psi

We dont think it is slipping

torque is a little higher as we were doing 2nd gear runs

but my friend who owns the dyno said it wouldnt be much less

sixshooter

iTrader: (12)

If tq is high then so is hp. One is a mathematic function of the other.

mx5psi

between 2nd and third low boost runs was .5rwkw so if they are relative im am guessing it wont drop by much at all

next thing is the run it down the quater i may just turn it up before i go

18psi

iTrader: (76)

this does not sound correct

turbofan

iTrader: (1)

Could be. Old style autos can result in some weird dyno readings. My buddy in the old turbo dodge minivan would usually have a graph that was shaped a lot like that, with somewhat similar numbers.

sonofthehill

iTrader: (1)

I guess we'll find out when it runs the 1/4 mile.
I never quite understand your time slips down there, there always seems to be a 1264 foot mark or something.
​​​​​

mx5psi

well it feels quick i am keen to run it down the track but not sure when i can go cause the closest track is two hours away and i work the weekends

it at least feels very quick and its fun to drive i might go out and bench mark it with some friends with a few v8's and see how it goes

patsmx5

iTrader: (16)

He later mentioned he dyno'd in 2nd not 3rd (3rd being 1:1 gear, 2nd being I dunno but > 1:1) So power is right, torque is off as we here quote wheel torque in the 1:1 gear and he apparently dyno'd in 2nd not 3rd.

mx5psi

Box has to come out

My auto builder called me as we had a discussion earlier in the day and there is an issue not a big one but its costing me power and not coming on properly oil pump in the box might need modding or changing he will also change the converter slightly

he thinks converter is flaring due to lack of oil pressure but is an easy fix

then we can turn it all up

mx5psi

its up and exhaust is out i need to have it all apart by Tuesday and they will have box all moded within one week

not how i planned on spending my weekend

patsmx5

iTrader: (16)

What do they think is wrong? What changes are they thinking of making to the oil pump?

mx5psi

He thinks there is not enough oil pressure or flow iam not sure which one which is screwing with the converter it should climb a little more power wise iam just happy i have got onto someone that has the time to help get it right as it is all trial and error to get it bang on he has said once its right i cant change turbo's as the converter will need to be changed

he thinks he left the stock MX5 oil pump in the box he will upgrade it to the Holden VL Turbo model which is the car they build these boxes for or modify the stock one which iam not sure of what entails he is also going to tweak the converter as he has said it may be a little loose