How Much Power Is To Much

[brad 110]

In my humble opinion if you tune your 3lt to make peak torque across the entire rpm range it will be a much more difficult car to drive, the sheer amount of torque that the three litre can develop at 3000/4800 rpm in an area where the boost is rapidly rising to target wastegate pressure will break the tyre contact patch, assuming your car is not FBW throttle then timing and boost are the only means of controling the power in the mid range. To tune to peak torque above this area and maintain peak torque for as long as possible is the key to tunning any engine.

Look to making modifications to the rear geometry as even the 33 has way to much anti squat in the rear to work with radial r tyre, which will make putting any more than 380rwkw to the ground through a radial challenging.

In my 32 it is a faster car with 490rwk even at a tight circuit like baskerville, as long as the power is controllable and follows throttle request (well as well as you could expect a turbo car to). There are large gains to be had in FBW throttle mapping getting rid of all waste throttle, ie only requesting 40% of plate opening if peak torque can be generated at this opening as this means a pedal reduction of 2% yeilds a reduction of horse power, increasing actual fly opening as rpm increases allways only requesting the min value to net max engine power at given rpm. Gear dependant boost pressure will also help and the holinger and quieff boxes have a voltage output making setting this function up very straight foward. cheers brad

[zebra]

all for the bargin price of $30k

[brad 110]

all for the bargin price of $30k

whats 30k?

[zebra]

hollinger, + setting up the fly by wire throttle + ECU to run it etc

[brad 110]

hollinger, + setting up the fly by wire throttle + ECU to run it etc

true you wont do what youve stated above for 30k if your buying new parts and paying someone to do any part oif it , tunning, install etc. What else other than a quaffe/holinger can you poke 420rwkwrwk through without it turning inside out in a race car if the car setup to put it to the ground.

[N1GTR]

OS Giken 5 speed kit - done

[irokin]

Jerico 4 or 5 speed road race box? Im surprised no one really runs these in Aus. I got rough figures of about $6500 for a 4 speed and ~$8000 for a 5 speed for an 800hp capable box when I looked into it. Edit: With a bellhousing. Oh, and the shifter mechanism will probably necessitate some cutting.

Edited October 8, 2011 by irokin

[Risking]

A mate has a 5 speed jerico in an FG XR8 that he uses for weekend warrior duties.

The initial cost of the transmission was okay, the bellhousing, clutch, flywheel, thrust bearing, tailshaft, selector and startermotor was the cost killer.

The total conversion set him back more than what an older H6S would have, now planning to remove it and I've ordered a brand new RD6 for him.

The jeri was good to use but the cost of maintaining it has proven to be expensive when it requires parts, so the hollinger is a better option.

[Risking]

Jerico boxes are also very common in Comodore cup cars,

2 of those cars I maintain have jerico boxes.

[260DET]

For sprints, where you are only allowed to pass on the straight, punch out of the corners is particularly important, you need to get past that slowbie you have been following ASAP and corner exit acceleration will do that for you. With my gearbox and diff an effective rev range of from 4000 to 7000 is required so it has to be well on boost and making good power at 4000 but not run out of puff past say 6000.

So it's not how much power is needed, it's what setup will give me a suitable and highest power spread possible. Makes the car nice to drive too which helps lap times as well.

[Super_Dude]

There are large gains to be had in FBW throttle mapping getting rid of all waste throttle, ie only requesting 40% of plate opening if peak torque can be generated at this opening as this means a pedal reduction of 2% yeilds a reduction of horse power, increasing actual fly opening as rpm increases allways only requesting the min value to net max engine power at given rpm. Gear dependant boost pressure will also help and the holinger and quieff boxes have a voltage output making setting this function up very straight foward. cheers brad

Would a cheaper alternative be 4d boost mapping with TPS vs boost and a Speed vs Boost map?

Edited October 9, 2011 by Super_Dude

[brad 110]

Would a cheaper alternative be 4d boost mapping with TPS vs boost and a Speed vs Boost map?

would be one way of doing it for sure, means running ignition cut for traction control though which is pretty hard on the engine if its on a percentage of cut for the majority of the lap. would be difficult to map due to constantly changing grip levels, maybe you could swing a 9 position trim of a gain compensation to vary it like we do to ulter the target slip percentage and rate in which throttle is slammed shut on slip break out.