Drag Racing: 325i vs 306 Rallye (GTi6)

[DmcL]

have a wee wager on with a mate about who will win. i was up untill today under the impression that his was standard but just found out hes a intake, exhaust and de-cat plus a few "little things".

what can i do to improve my chances of whooping that french turd for free or very cheaply? lol

my mods are:

- 325 sport 15's (not really a mod but i have a feeling im gonna need to launch the s**t out of mine to have a chance)
- 4.10 differential
- Z3 M coupe gear stick (short shift)
- unknown spec 6850rpm redline chip (hopefully have a copy of an alpina B3 chip by then)
- universal filter on the airflow meter with large air feed (in the process of making a covered ramair setup for it, just have to finish the "airbox" lid)
- a spare standard exhaust mid section, cut the middle box out and planning to join the 2 and run a 2.5-3 inch single system from downpipes back
- lumenition MS4 ignition coil
- all my junk/tools/jack/etc in boot (must be a good 10 stone in the boot at least, i will also remove the spare)

all i have that i could try for free is a pair of E36 standard rear springs off my old 318i, line of thinking is E36 is a heavier car so rears should be a little stiffer which might help off the line as im on standard E30 suspension and las time i launched on my 14's in the dry i got a lot of wheel hop in 1st gear. launched from 2000rpm for minimal spinning but also no bogging, ended up hopping my way up 1st gear. think the 15's and the E36 rears might help with that?

so given all of that what do we reckon? im kind of hoping if i complete the intake, build the exhaust and empty the boot i might stand a chance of winning with a decent launch.

what do u reckon?

[steve_k]

you're gonna hate this but it all comes down to the driver if you ask me lol.

let us know how you get on.

[DmcL]

well i can drive and with the Z3 M coupe stick in her gearchange is not the typical rowboat affair like any other 5 speed (even so called short shift kitted) BMW's. that and the 4.10 allow me to chirp the tyres into 2nd gear on dry asphalt, slight spin on tarmac. no dumping the clutch or shifting with the revs up, i can chirp 2nd even if i shift up to 2nd at 3000rpm in 1st.

just wondering if im crazy thinking that by pulling the excess weight (not forgetting that uber heavy backbox being removed when the dp back system is made) and finishing the mods i have on the cards right now it would be a fairly even race.

the 306 is 167bhp standard and is also a lighter car and id say the rallye model is lighter than the GTi6 but with the same engine/box. add say 10-15bhp for intake/exhaust/decat/other and id need to be in the 180-190bhp region and of a similar weight. thinking a good launch could be the trick as i doubt i could get the E30 to a similar weight without lots of interior stripping. also not sure what the deal is with 5 speed vs 6 speed. i know most 6 speeds have 6th set as the economy gear wherear most 5 speeds have 5th set. with my 4.10 5th gear is nearly 1:1, think its something like 0.86:1 if memmory serves so i dont really have that eco gear anymore lol

[Ze-German]

save as much weight as possible!
get any mats, rear seats etc out any cds if u can take the headunit out easily that would be good if the door cards come off easy then go to thatt extent!
service the engine ie oil filter new oil etc etc etc
the air filter should have a ram air pipe make sure it is facing onto the filters front not onto the side otherwise the air will blow thorugh the filter
new tyres??
have a poo before the run aswell (extra pound saved )
run minimal fuel littrally enough for 1 run save 40kilos
perspex windows????
any engine covers that dont need to be there can go!
make sure the timing is right on the engine and that everything is clean!!!


apart from that theres not alot else!

[Jhonno]

For a start your plans for the exhaust sound like a great way to lose power

[Jon_Bmw]

You'll be pleased to know the 'intake' exhaust and decat will do half of fuck all really. Maybe 5bhp from the decat, but even that is unlikely. Not sure what you mean by intake, I presume you mean a shit cone filter, rather than ITBs.

If it has ITBs and the associated cams, you are forked.

From a standing start they are not that quick, but get one moving on an A road, and you have no chance. From a standing start to 60 is your only chance IMO.

You need someone who can drive, to pilot the gti6 lump as if you don't know what you are doing, you will not make the most of the engine.

Anyhow, both cars will be similar, and neither will make the other look stupid.

[Jon_Bmw]

The 306 weighs: 1163 kg

So no real difference to a 325. You mate wants to get that lump in a 205. 830 kilos ftw.

[dazleeds]

think is will be won in the first 100yards

whoever gets it off the line best

[steve_k]

do us all a favour & when you hold this drag race then why not film it & post it up for us all to see??

[Lloydie38]

The french thing will break before it gets the the track. You've won.

[m_jermyn]

get some race fuel.

[12345kevin]

Be prepared to loose, i would guess

If u're going over the quater mile, don't put in the 4.10 diff as there will be an extra gear change, and more wheelspin. Keep to a 3.64 and you will get to the line in 3rd.

[Jhonno]

get some race fuel.

On a car without knock sensors that is mapped for 91 RON.. Great Idea

[DmcL]

Be prepared to loose, i would guess

If u're going over the quater mile, don't put in the 4.10 diff as there will be an extra gear change, and more wheelspin. Keep to a 3.64 and you will get to the line in 3rd.

4.10 was always in it. car was originally a 4 speed auto but i converted it. i reckon ill get off the line quicker than him. i can takeoff in 1st with no spinning at all, just slip the clutch a little initially and step on it immediately after coming off the clutch. dunno if that would be quicker than launching with a little spin or not tho. not too worried about the extra gear change as the Z3 M coupe stick makes it extremely short between gears.

was actually thinking of trying to get it on video.

[e301988325i]

15psi in the rear tyres for grip, 50 in the front for low rolling resistance.

You want softer rear springs if anything to aid rearward weight shift and hence more traction.

Keep the weight in the boot for traction off the line.

You could remove front passsenger seat.

Make sure your car is nice and warm, especially the gearbox oil to aid smooth changes.

Find the release point of the clutch pedal and make a physical stop underneath it, saves about an inch of clutch travel if all is working well!

Check condition of engine and gearbox mounts, propshaft guilbo and replace if perished to minimise losses. These are easy to change, diff bush is also worth checking if you've got time and tools. . .