"spi sucks fit a carb"

[Aragorn]

well further to my spi tuning guide a wrote i finally managed to get me bro's car on a rolling road with the mods done in the guide (gte cam, decat, GTE exhuast manifold and downpipe, ashley GTE system)

car made 64bhp at 6200rpm (rev limiter) and 62lb-ft of torque at 2500 and 4500rpm (with a slight dip in the middle), and was leaning out a bit at the top (13:1 upto 4500rpm then leaned off to 14.5:1 from 4500 to limiter)

pity we cant increase the rev limit as the graph is a streight line right upto the limiter

it feels great to drive and that almost flat torque curve from 2500 to 4500 defo shows especially in lower gears and with it being stripped out with the buckets it keeps with a std SR reasonably well (and it ran an 18.8 quarter)

got some more mods up my sleeve but im trying not to move the power too far up the revs due to the limiter being so low, think im gonna try a mild cam, larger injector and possibly some headwork

[Nick]

sounds good, 64bhp isn't bad for a 1.2i

am i correct in thinking they are nearly 45bhp standard ?

[david dixon]

sounds good, how much was it before hand?

[Aragorn]

yup 45bhp at 5000rpm and 63lb-ft at 2800rpm

although i havent got more torque, my torque graph has a nice large plateau now rather than the small peak around 2800 that exists on the std engine

[david dixon]

well thats a good hike for mods that dont cost a lot! :D

[Nick]

excellent, so it really pulls more through the low end of the gears ?

[Aragorn]

pulls hard to the limiter in 1st and 2nd, doesnt really have the power to pull that well in 3rd and 4th (3rd is ok 4ths just shite )

could really benefit from a CR boxi think, its got std 4speed wide ratio box just now

as i said got some more mods up sleeve, gonna try n get rid of the leaning out at high rpms, perhaps push the ignition advance forward a bit and some other ideas i have swimming round in my head

gonna be taking a trip to scrappy soon to size up some bits

i'll scan and post the bhp and torque graphs when i get the chance

[Adam]

well further to my spi tuning guide a wrote i finally managed to get me bro's car on a rolling road with the mods done in the guide (gte cam, decat, GTE exhuast manifold and downpipe, ashley GTE system)

car made 64bhp at 6200rpm (rev limiter) and 62lb-ft of torque at 2500 and 4500rpm (with a slight dip in the middle), and was leaning out a bit at the top (13:1 upto 4500rpm then leaned off to 14.5:1 from 4500 to limiter)

pity we cant increase the rev limit as the graph is a streight line right upto the limiter

it feels great to drive and that almost flat torque curve from 2500 to 4500 defo shows especially in lower gears and with it being stripped out with the buckets it keeps with a std SR reasonably well (and it ran an 18.8 quarter)

got some more mods up my sleeve but im trying not to move the power too far up the revs due to the limiter being so low, think im gonna try a mild cam, larger injector and possibly some headwork

64bhp, that is quite a great increase for basically, mods of a higher spec nova(gte)
I wouldn't expect the increase to be that much, so it has suprised me a lot.

It at least gives 1200spi owners some hope :wink:

[Aragorn]

the rollers were maybe a bit optimistic but not that bad really

a totally bog std astra X20XEV run 142bhp which is 4 up on std

the nova ran 52bhp at the wheels

if we ignore the calculations for flypower and just assume 15% transmission losses that gives us 52*1.15 = 59.8bhp

so even 60bhp isnt too shabby for the mods

the gte cam does increase valve lift by about 40-50% tho

std 1.2i has about 4.2mm lift and GTE has 6.12mm

[Adam]

How it struggles to the limiter in 3rd and 4th sounds rather much like my 1400spi astra, basically struggles reach 5k rpm in 3rd. And i have no comment in 5th gear
I don't even bother with 4th/5th gear ::