Big HP Starlets - Putting Down The Power
- Thread starter Gee
- Start date
Spoonz
Member +
haha great answer
Aga
Member +
higher rev limit does wonders on the quarter mile, however the thing is, will you have power in that area? you will need big cams, and a balanced engine to rev high and make power (and a turbo that will not fall out of efficiency at such high rpm...)
i hear engine shops here talking about built 5E's that are safe to go 8500...
Hi, i was reading the forum and came across this topic thought i might add.
I can try and explain how I try to achieve good traction!
The basic thing you do not want to happen in weight transfer off the front wheels during launch,so for a start jack the back off your car up,heavy rear springs or if you like fit those caravan towing aid rubber spacers into the coils of the rear springs,the stiffer the better but not solid ,I now use solid packers on my shock absorbers,with a 1" bump rubber ,the car weight sits on the shocks.
At the front,you try to eliminate droop,in my case I have adjustable shocks so I wind the rebound to max, if you dont have adjustable shocks then a cheap fix would be too install droop strapsmade of steel cable.
Lower control arm position will effect dive or anti dive,so fit spacers between the body and the rear mount of the front arm(mine are 15mm long)
Axle tramp is very much a killer of a good 60ft,so heavy eurethene engine mounts are a must,my car has a very solid strut brace which has an equaly heavy engine steady brace.
All the power is trying to tear the front wheels off the car so it moves this action to the weakest area which is the lower control arm rubber mounts, a minimum fit eurethene mounts here,mine has spherical bearings and the rear mount is steel with a phosfor bronze bush insert.
Axle tramp can be minimized if the front anti roll bar is as solid as possible connecting onto the lower control arms,minimum of eurethene or for drags only go aluminum,solid.
I think that covers the basics of the suspension,it wont really help if you dont have sticky tyres,I use Toyo 888 205/60/13" for drags that require a street tyre and our team holds the current street tyre fwd Australian record, they work well,but it is important to do a massive burnout. For slick record attempts we use MT slicks again a good burnout helps.
A lot of guys are worried about breaking gearboxes when they launch hard and so they should be ,Ive broken my share too!,but you have to decide what your aims are,if its to have fun then a soft launch putting power down gradually might be for you, I have spent a lot of money on my drivetrain components so they wont break and if they do then so be it, all in fun.
A locked diff will help, not an lsd but a locked diff big difference, tyre pressures is a big part of grip, we run as low as 8 psi if the track does not have the grip we are after, droping the pressures after the run is a must, you dont want 10psi cold pressure because after the burnout its going to be anywhere between 5 and 9 psi higher, so only take readings when the tyre is up to temp.
So bearing in mind you all don't have these components in your cars,this next bit may not be possible for you to achieve,I launch at 8,000rpm on the rev limiter ,no slipping of the clutch ,just dump it and mash the throttle(this is if the track is prepped and the tyres are hooking up good (oh ,only on the slicks too!!!).This last time i went I was launching at 6,000rpm and the tyres were spinning,then we dropped the pressures and it bogged at 6,000 then gripped good.
Street tyres I was launching at 5,000 rpm but sliding the clutch, The driver can make a large difference, you dont want to much traction as the car will bog when it grabs grip, and too much you go nowhere, so you need to find the happy middle for the track that day. Anyway the best thing is have a look at your suspension, get decent tyres and go and practice.
I can try and explain how I try to achieve good traction!
The basic thing you do not want to happen in weight transfer off the front wheels during launch,so for a start jack the back off your car up,heavy rear springs or if you like fit those caravan towing aid rubber spacers into the coils of the rear springs,the stiffer the better but not solid ,I now use solid packers on my shock absorbers,with a 1" bump rubber ,the car weight sits on the shocks.
At the front,you try to eliminate droop,in my case I have adjustable shocks so I wind the rebound to max, if you dont have adjustable shocks then a cheap fix would be too install droop strapsmade of steel cable.
Lower control arm position will effect dive or anti dive,so fit spacers between the body and the rear mount of the front arm(mine are 15mm long)
Axle tramp is very much a killer of a good 60ft,so heavy eurethene engine mounts are a must,my car has a very solid strut brace which has an equaly heavy engine steady brace.
All the power is trying to tear the front wheels off the car so it moves this action to the weakest area which is the lower control arm rubber mounts, a minimum fit eurethene mounts here,mine has spherical bearings and the rear mount is steel with a phosfor bronze bush insert.
Axle tramp can be minimized if the front anti roll bar is as solid as possible connecting onto the lower control arms,minimum of eurethene or for drags only go aluminum,solid.
I think that covers the basics of the suspension,it wont really help if you dont have sticky tyres,I use Toyo 888 205/60/13" for drags that require a street tyre and our team holds the current street tyre fwd Australian record, they work well,but it is important to do a massive burnout. For slick record attempts we use MT slicks again a good burnout helps.
A lot of guys are worried about breaking gearboxes when they launch hard and so they should be ,Ive broken my share too!,but you have to decide what your aims are,if its to have fun then a soft launch putting power down gradually might be for you, I have spent a lot of money on my drivetrain components so they wont break and if they do then so be it, all in fun.
A locked diff will help, not an lsd but a locked diff big difference, tyre pressures is a big part of grip, we run as low as 8 psi if the track does not have the grip we are after, droping the pressures after the run is a must, you dont want 10psi cold pressure because after the burnout its going to be anywhere between 5 and 9 psi higher, so only take readings when the tyre is up to temp.
So bearing in mind you all don't have these components in your cars,this next bit may not be possible for you to achieve,I launch at 8,000rpm on the rev limiter ,no slipping of the clutch ,just dump it and mash the throttle(this is if the track is prepped and the tyres are hooking up good (oh ,only on the slicks too!!!).This last time i went I was launching at 6,000rpm and the tyres were spinning,then we dropped the pressures and it bogged at 6,000 then gripped good.
Street tyres I was launching at 5,000 rpm but sliding the clutch, The driver can make a large difference, you dont want to much traction as the car will bog when it grabs grip, and too much you go nowhere, so you need to find the happy middle for the track that day. Anyway the best thing is have a look at your suspension, get decent tyres and go and practice.
GTti
Member +
Perhaps the most sensible option is to mod the car within reason in the first place rather than having an obsession with figures 
I bet you could wind off 5 or 10 psi through 1st 2nd and most of 3rd and end up with an identical 1/4 mile time.
I just might add that all this info is a perfect recipe for ruining your car, box, clutch, and everything else in between the flywheel and the road wheel.
Maybe I just have too much mechanical sympathy.
I bet you could wind off 5 or 10 psi through 1st 2nd and most of 3rd and end up with an identical 1/4 mile time.
I just might add that all this info is a perfect recipe for ruining your car, box, clutch, and everything else in between the flywheel and the road wheel.
Maybe I just have too much mechanical sympathy.
Gee
Member +
Well, this thread was posted for people that may have a track dedicated car or who may consider blowing a box to get a time they want to put down for the rest to beat.
Obviously somethings are out of means, I would not go all out with some of the suggestions above either, but it's good info. Which partly is what this forum is all about.
Obviously somethings are out of means, I would not go all out with some of the suggestions above either, but it's good info. Which partly is what this forum is all about.
eptercel82
Member +
EXCELLENT first post there i think ive seen him in au starlet club?? right.
all that said is real good ive gone down as much as 6psi on my slicks at the track and since im on a stock ecu im at the 7200 rpm launch and dump it!! and so far with a stock c52 trans and a phantom grip ( which sucks) im getting 1.74 60ft's in the process of welding the diff and leaving it a drag queen! so good luck to all
also developing some traction bars to preload the front arms similar to the hondas cuz i noticed under hard loads due to solid hubs on the clutch that the tires would fluctuate almost .50-.75" when engaging the clucth we'll see how it works out and hopefully it will bring those 60ft times lower..
all that said is real good ive gone down as much as 6psi on my slicks at the track and since im on a stock ecu im at the 7200 rpm launch and dump it!! and so far with a stock c52 trans and a phantom grip ( which sucks) im getting 1.74 60ft's in the process of welding the diff and leaving it a drag queen! so good luck to all
also developing some traction bars to preload the front arms similar to the hondas cuz i noticed under hard loads due to solid hubs on the clutch that the tires would fluctuate almost .50-.75" when engaging the clucth we'll see how it works out and hopefully it will bring those 60ft times lower..
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Gee
Member +
What negative effect can the clutch? It does not slip or anything like that.