Discussion
QBee said:
I have a feeling that both Daz's 345 bhp and Chilli's 360 bhp have been achieved by sacrificing torque to get bhp.
Which is more important on the strip?
Yes I agree with that, I saw the graph Derek posted on Facebook and it is pretty much 340ft/lb flat from 1500RPM which would make it 'feel' proper quick and very nice to drive. You can sacrifice BHP for torque using a higher lift cam which is great on track where you can keep the revs up. Not sure about dragstrip, probably torque for the first 1/8 and BHP for the second 1/8 BHP. I know when I have raced Speed Six cars I can launch mine off of the line with torque and gain a couple of car lengths, by the time I have reached 1/8 the speed six can is starting to gain.Which is more important on the strip?
What cam have you got in there Derek?
MPoxon said:
What cam have you got in there Derek?
Its a Crower 50304 solid.I think Dales rollers are very conservative. There is a healthy hike in torque.
So a rather eventful weekend.
I put the car on the dragstrip at Ten Of The Best on Saturday morning and did 2 runs NA. The first run had a fair amount of wheelspin after just chirping the tyres to clean them off. I ran 12.57 at 117mph on a poor 60 foot time of 2.01. The best i have ever done on a dragstrip NA iis 12.41 @ 113 so this run proved to me straight away the engine had more grunt. I gave the car a quick look over then went out again. I tried a burnout but it proved impossible on the dry concrete surface. So again the launch was not perfect. I ran a new NA PB of 12.35 @ 116 with a 60 foot time of 1.91. At this point i could not have been happier.
So it was time to set a proper ET and the nitrous bottles were opened. Again no burnout, so a 60 foot of 1,86 was all i could manage but ran 11.24 at 135 mph. I could not believe ths terminal speed as it was over 5 mph faster than ive ever gone on the 1/4.
I was happy so left it there and watched some of the other competitors in allsorts of mainly Jap 4WD stuff.
Later i decided to finish the day with a run at the kilometer. So i lined up in the left lane and signalled to the startline marshall that i was attempting the full 0.6 mile run to test top speed. I set off well OK with a 1.84 to 60 foot, but as i approached the 1/4 there was a problem. Then i saw smoke in the mirror and from under the bonnet so backed off. I still ran the fastest 1/4 of the day at 11.18 at only 121. Then there was a lot of smoke as i slowed and stopped by a marshall van. I popped the bonnet to fine the offside exhaust manifold with flames licking out from where the primaries meet. A few big puffs and it was out. Towed back to the pits and pulled the plugs on that side. 3 were wet with speckles and number 8 was completely white. I took the nearside plugs out and they looked fine. The engine spun over on the starter ok with the fuel pump switched off but it looked like oil was being spit from the plug holes.
Guess we will have to wait to Friday to find out the full extent of any damage when i strip it down. I an too tired to do it now.
There were literally no miles on the car. Only cam bedding then we loaded it up on Dales rollers to bed the rings in. This worked as it was fairly smokey at first with the thin break in oil. Was much better later with vr1.
I was suspicious of those terminal speeds but hear the GTR guys had matching numbers on their fancy data loggers.
I had the same jets on the nitrous systems as I had previously and I knew the AFR used to go off scale rich when it was 3.5 bar fuel pressure. I am now back to 2.5 bar so was careful to watch the gauge. It hovered around 11:1 which I thought was perfect but am now thinking that average on all cylinders may have left 1 or 2 to lean out. We will find out come Friday when I pull the head.
I was suspicious of those terminal speeds but hear the GTR guys had matching numbers on their fancy data loggers.
I had the same jets on the nitrous systems as I had previously and I knew the AFR used to go off scale rich when it was 3.5 bar fuel pressure. I am now back to 2.5 bar so was careful to watch the gauge. It hovered around 11:1 which I thought was perfect but am now thinking that average on all cylinders may have left 1 or 2 to lean out. We will find out come Friday when I pull the head.
Looking forward to getting home tonight and start the strip down. It's been on my mind all week and I fear some serious damage.
Also after repairs I am fitting a vernier timing set and setting the cam with 4 degrees retard. Then the nitrous system is getting a makeover and will be operated using the MS2.
Also after repairs I am fitting a vernier timing set and setting the cam with 4 degrees retard. Then the nitrous system is getting a makeover and will be operated using the MS2.
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