Whipple 3.25" pulley numbers: 807.45 rwhp, 764.25 rwtq !!
- Thread starter 632C2
- Start date
Thanks, Tony. As I have said many times, your help is invaluable! There you have it on the A/F - from someone that should know.
Steve
Fast Freddy
GPS'D 225 MPH
so what kind of spark plugs are you guys running at these 19+ psi boost levels and how much timing are you running?
I am running the TR6 plugs but they are too hot for this application. If I were to continue with this combination, I would go to a colder plug.
As far as the timing, I was at 21 degrees at maximum horsepower.
Steve
B O N Y
MODERATOR & FGT OWNER
Fast Freddy
GPS'D 225 MPH
if i was you i would back the boost down to 19 psi and run 100 octane gas. 21 degrees of timing is way to much timing for 22+ psi especially with less than 100 octane gas. in my lightning i have a "diablo" flip chip which is the same software that is used for the GT's. on 91 octane i run 13 degrees of timing at 16 psi and when i flip the chip to the race program my timing advances to 19 degrees and i run 100 octane gas.
i run those NGK TR6 plugs in my camaro because i have nitrous. are these plugs the stock heat range for a GT or are they 1 step colder? if they are 1 step colder than stock then you should be fine.
as far as your 12.0:1 A/F ratio is concerned that would be perfect for 19 psi. the only problem i see here is too much timing relative to the level of fuel octane you are using assuming the TR6 plugs are 1 step colder than the stock plugs.
i run a intercooled whipple supercharger on my fuel injected 503 ci BIG block V-8 muscle boat engine and i luv it. :thumbsup
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BlackICE
GT Owner
Freddy what is the difference in HP did between pump gas and the 100 octane with more timing.
BlackICE
BlackICE
You are preaching to the choir. As I stated earlier, my next step is the 3.50" pulley that is good for about 19psi of boost. TR6's are colder than stock but I am not sure how many steps colder.
Steve
Steve
Fast Freddy
GPS'D 225 MPH
my lightning dyno'd 30 more rwhp with 6 degrees more timing. when i "flip the chip" on my diablo which advances my timing from 13 degrees to 19 degrees i have to run more octane or my engine will detonate and i could blow my pistons. with a GT motor and whipple making 800 rwhp i am guessing that you would see a 45 rwhp increase off of a 6 degree change in timing. but again you will need to increase your octane from 91 to 100. if you run 104 octane unleaded you could advance your timing another 2 degrees which would probably bring on another 15 rwhp at this level.
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BlackICE
GT Owner
Are there any issues with exhaust gas temperatures with 91 octane gas and retarded timing? It seems hardly worth the effort if you can get 700+ HP on 91 pump gas to get another 35-45 hp with 100 octane gas with all of the hassles, unless there is more to it than just HP.
BlackICE
BlackICE
Fast Freddy
GPS'D 225 MPH
this would be a very wise choice becasue on a dyno your supercharger stays nice and cool and does not get heat soaked like it will when out racing on a 80+ degree day. the faster you spin your blower the more heat it throws off too. so the reduction in boost will help to shed the heat too. since the plugs are already 1 step colder than stock i would stick with them. NGK TR7's are another step colder than the TR6's but in chevy's LS series engines sometimes they don't idle so well. i am not sure how they go over in fords but it seems from memory that guys are runing them in heavily modded lightnings and blown cobras. but since you are gonna turn your boost down you shouldn't need them anyway. :cheers
Fast Freddy
GPS'D 225 MPH
i think 8 degrees of timing in a + or - 800 rwhp GT is gonna be more like 60 rwhp. and in a race that can be the difference between winning and loosing and so imo its worth the effort.
I agree there is power in the timing but not as much as you would think. There is a major difference between the 2V Lightning head and a 4V GT head..
Example that would show the difference is an 03/04 Cobra vs the 03 Lightning. Whereas the Cobra can run in the 20-22 degree area safely the Lightning would destroy the piston in a heartbeat and is kept at a max of 17 in race trim (Normally)
The 4V chamber/piston design is much less prone to detonation although at the higher boost levels a 7IX would be a better choice over the 6's..
TonY G
Example that would show the difference is an 03/04 Cobra vs the 03 Lightning. Whereas the Cobra can run in the 20-22 degree area safely the Lightning would destroy the piston in a heartbeat and is kept at a max of 17 in race trim (Normally)
The 4V chamber/piston design is much less prone to detonation although at the higher boost levels a 7IX would be a better choice over the 6's..
TonY G
SLF360
GT Owner
spark plugs
Tony,
so what are the best plugs to take for a regular blower with smaller pulley here, and what the spacing ? I heard of Denso's here, but not familiar. You were experimenting way back on Piko's car with different sparkplugs, so is there an advice for us normalos mildly souped up ones?
Stefan
Tony,
so what are the best plugs to take for a regular blower with smaller pulley here, and what the spacing ? I heard of Denso's here, but not familiar. You were experimenting way back on Piko's car with different sparkplugs, so is there an advice for us normalos mildly souped up ones?
Stefan
Stefan! Off the subject, but are you going to try to see Joe when he is in Italy?
We have settled on a 8IX at the moment but may change to a new plug that I will be discussing with the manufacturer at the PRI show tomorrow.
Torrie made 1046 RWHP on Race Gas with a 22C, however he has the 7IX in his now.
At 600-700 on Pump Gas I would use the 22's unless the car is being used to its potential and then go to the 6's or 7IX.
There is s noticeable idle difference with the colder plug but its not to unpleasant unlike the alternative of replacing an engine..
TonY G
We have settled on a 8IX at the moment but may change to a new plug that I will be discussing with the manufacturer at the PRI show tomorrow.
Torrie made 1046 RWHP on Race Gas with a 22C, however he has the 7IX in his now.
At 600-700 on Pump Gas I would use the 22's unless the car is being used to its potential and then go to the 6's or 7IX.
There is s noticeable idle difference with the colder plug but its not to unpleasant unlike the alternative of replacing an engine..
TonY G
Be careful out there using a plug that is listed by the mfg as colder (many times they are not colder).
Some plugs actually run hotter under long duration use (road race, etc).
Use a heat gauge and real world experience.
Some plugs actually run hotter under long duration use (road race, etc).
Use a heat gauge and real world experience.
Trackday I would agree especially after seeing what Bob Ida does. He has also found that the colder plugs are not colder by using the ehat gauge.
Good recommendation.
Dave