Project VF Boosted Part II - The Cram
So as a quick recap leading on from PVFB and where we left off... we were in the 9.60s at 143mph. Nice place to be hitting off from but we hadnt come this far to end it there.
With PVF and PVF2 we had chased power by moving air with larger and revised camshafts, displacement and header/ intake designs. This time we had an adder so if we want more power just add BOOST?! Well lets see...
Time is short and waits for no man and with a zillion things on the go like we had building the new shop while running the business poor old PVF2 and PVFB were on the back burner. But onto the dyno. With no time to waste...first upgrade was to hit it with a NW102B throttle body. Now our previous testing with this mod showed it was far from a cost effective way of getting more power. We had never done it on the 2650 so it was time to bolt one on. Results were the same as we had previously seen...struggled to gain one psi in boost and netted sub 20hp pretty much confirming the 90mm unit isn't holding the blower back by as much as some would think. Or is it the inlet of the charger holding it back? Lets see...
Best value for money we had always seen from 5mm of pulley! Seeing as we were spinning a 75mm we decided to bolt on the smallest available in a 65mm and turn it up. The gains were immediate taking boost to levels no smaller blower will ever see regardless of porting and supporting mods. Clearly with the boost increase the inlet of this charger is not the choke point. Are there gains to be had there? Only testing will tell but at this point boost is increasing at the same rate as it did before 15psi so it appears to be moving air well..
The big dollar TB gave us 1psi. 10mm of pulley gave us 3psi!! Now that is value and clearly shows the blower is still in its efficiency range to be pumping more air with that extra speed. Touch up of the tune as best we could on the dyno but tyres were stuggling as can be seen on this graph but gives us the data we need to get it in the zone even if the queen numbers aren't there. Little 6.2L is poking over 800 at the tyres with slip. The track will be the master on this one. The curve starting later on the graph? No chance the lock up was going to hold at this level...so it sits on the converter. We try to start them later in that instance to prevent it cooking the trans out of it.
Just incase you didn't know reading this...SQP is a Premium Dealer for Harrop products. This is an upcoming special we have on the horizon...get on it!! Mention PVFB on booking for free infill panel.
Racing is a fickle mistress and disasters are only around the corner at any time. We got the ute to the track full of anticipation and enthusiasm only to have dark hand of bad luck ruin the evening. It would be safe to say we found the torque limit of the OEM tailshaft...
You reckon that made a racket?? You bet!! Soft leave on the first lap after the upgrades it got a little unsettled half way through 1st gear and BANG!! I was straight off the throttle and it never even touched the limiter...reflexes like a cat the old bloke! LOL!! (I have to log to prove it too!) Sitting in the car rolling down the side of the track hoping I make it to the finishline gate the tach was showing the engine still running so it is good. But we had no drive and a heck of a lot of rumbling from under the car. They say what doesn't kill you makes you stronger - well best we apply that theory to the shaft. We constantly get told the donuts are piss etc. This thing didn't bother a 155000km old donut. It destroyed the tubes and cracked EVERY weld in the shaft. Onto our good friends at Driveshafts Australia DSA. Paul has built shafts for SQP for near 30 years from everything up to our Top Doorslammers builds. They have some of the best balancing equipement and machines for purpose made by man. Check out the upgrade!
We revised the tube size and diameter. Upgraded the centre bearing and uni but as can be seen we left the donuts alone. Back in the car.
Well that should get the job done with power tranmission to the diff. Back to the track.
Can you believe that when shit is happening...it just keeps happening? Test day - 1st run out...DOESN'T MOVE 10 FEET AND BREAKS A DRIVE SHAFT IN THE REAR END! PICKLE ME GRANDMOTHER and stuff like that!! On the phone and a new one is on its way...car jacked, parts and tools ran to the to the track...others borrowed and we were back in action. Eat your heart out McGiver.
Day was lost but into the evening we headed.
Getting the ute off the line harder we were into the 9.50s! And deep too! 60 foot was lame as I was still a bit gun shy after the previous two breakages.
Time to man up and get on with the show.
The 60 was smoking with a 1.42! It trucked through the 1st half of the track but we lost the belt at 1000 foot. 9.45@ a slowing 140mph. Into the 40s and it would of been deeper too if the belt had stayed in the game. Sweet and Sour at the same time.
Back to the shop and some time investigating why the belt was all of a sudden an issue. It was found that the idler was starting to lay over after the blower drive. Now this idler bracket was never engineered to be ran anywhere near as hard as where we were taking it with the tensioner and speeds we are seeing. The reason SQP had stayed inloop on this is to utilise the tensioner we have used for many years on previous blower installations. It gives the highest loading on that 8 rib we can get out of any tensioner and over a longer range than any other available. In fact 30% more than a LSA tensioner can deliver. But we have an issue. So a redesign was in order. Nothing more was added than a stabilising bracket supporting the idler via the SQP billet power steer delete as can be seen in the pic below. Taking things to another level is how innovation and development occur. Something SQP is no stranger to. We are seeing over 20psi (yes they make more at the track with the OTR giving a ram effect once you get the car moving) into this engine out of the Harrop FDFI 2650. That is mental in anyones book for a street blower. A redesign is in play for the idler bracket that will be available soon... Again - thank you to Heath and the team at Harrop for your support on this Project. It is great pushing the boundaries and having the back up of Australia's biggest aftermarket performance manufacturer.
Did someone say Harrop FDFI 2650? SQP were the first to offer this as an upgrade on LSA engines replacing the 1900. Check out the pricing and packages below.
But back to the track. Time to get a driver in the car sub 100kg and see where we can get this rocket to go and prove we have the belt issue sorted. In steps Shane Joyce. At a wet 72kg he is worth a good .12 seconds in the other PVF cars so lets see where he can take the blown beast!
Few mishits as it takes a bit of technique to make the blown heavyweight get off the line - too soft and it is slow - too agressive and it just takes the drag radials clean off it. That is the nasty thing about blown cars...you gotta drive them! No boost control and timing curves to make up for what isn't getting done behind the wheel. No bump boxes and line locks...this is all on foot brake and loud pedal. But as all good drivers, he got it going! The mph showed we had the belt issue sorted! But you can do some more on that 60 foot Shane!!
And he did!!
This email address is being protected from spambots. You need JavaScript enabled to view it. ! SMOKING!! That is a cool way to finish off the season. After the breakages and issues it was awesome to end on such a high note.. I set the season goal at 9.30s and friends looked at me like i'd been in the sun too long. Something about stress causing the old bloke to start cooking off! But we got there! it is very rewarding to validate our SQP PWM controlled returnless fuel system, SQP conrods, SQP cam design, SQP transmission calibrating in conjunction with a capable builder in LSX Powertrain (thanks Rocky) keeping the 6L80E alive cranking over 1140 weight shifted horsepower out of the 6.2L LS3 base. All GM OEM controllers. All tuned MAFLESS utilising GM Coefficents to control fuelling and keeping the torque models pure via EFILive.
Where to now? Well with boost comes the dreaded intake heat. Boost doesn't make power- it is a measure of restriction and it takes power off the crank to make with a blower. Moving air through the motor makes power. If higher boost sees more air moving into the engine - power comes up but how much extra air is actually entering the engine? And how much will it lower intake temps? The heat we are seeing is at levels smaller blower get to at 15psi so it truly shows the efficiency of the 2650. To move more air we better get the covers off this thing and start messing with a new cam. As seen here the SQ53B is no slouch but in will get the the SQ60. It has a history and has powered some of the fastest PD cars around. Best we get it into PVFB. Onto the hubs at Tune Corp for a baseline power number 1st...we have done the Cram - now it is time for CAM! Might even do an oil change too. Back soon!
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Project VF Boosted Part III - THE CAM... >>
