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[I'm a Red Motor fiend]

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Dyno session #1

Hit a couple of hurdles, had to mod the pipes to fit no biggie.
Brand new out the box Holley regulator didn't regulate shit so changed it out.
Fired it, bedded it, put the inner springs in.

Tried UM, UP, UU, and UX needles, UX got us the closest.
Tried heavier dash pot springs but the pistons wouldn't lift fully so went back to the lightest springs.
Tried SU oil, settled on 30 weight in the pots.

Set float levels higher, fuel pressure up to 4psi.

Little rich through the midrange.

Started leaning out around 4800 and not a happy curve after that.

Anyway, long story short, not enough fuel! Will source some grose type needles and seats and think we will be ok.

Kinda kicking myself for not covering this base to start with.

Made 245 ftlb and 263hp. There is a lot more in it once we get the fuel in.

Cam comes on violently around 4000rpm and starts to go ballistic but then unfortunately starves and leans out.

Hoping to make power to around 6500rpm.

Stay tuned for dyno run #2 sometime in the next week all going well.

[claysummers]

Sounds like you’re all over it


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[TK383]

Yeah, bugger with the leaning out, she's on a mission till the fuel supply tapers off!
Looks like peak torque will occur around 4800rpm, so peak power should be around 6300rpm.
Looks good to hit 300hp, but hard to tell till we can keep fuel up to it.

Yeah, bugger with the leaning out, she's on a mission till the fuel supply tapers off!
Looks like peak torque will occur around 4800rpm, so peak power should be around 6300rpm.
Looks good to hit 300hp, but hard to tell till we can keep fuel up to it.

[I'm a Red Motor fiend]

Twas a long day, started at 8.30 and ended just after 11pm I reckon. TK and Con at Competiton Automotive were brilliant.
And Tony, we will no doubt beat
this thing into submission as you would say!!

[LC-GTR-1969]

I had similar woes with my old engine when it ran 2 inch SUs. The lightest springs seemed to be good till about 4500 then would lift too quickly and give lean spikes, it would catch up with itself kind of but I never got a clean curve with the light springs. I had tried different weight damper oil but it never seemed to settle enough in my setup, or maybe just my limited tuning abilities...  I ran 11oz springs in the end (from memory) and they ended up being the best compromise for me. UX needles worked well in my setup also. 

 

Sounds like it should be a great little engine when you get it sorted. Nice work mate. 

Edited by LC-GTR-1969, 26 January 2020 - 06:21 AM.

[Ando]

Great thread Adam & luv Tony's engine building skills as well!!

 

I'm fairly ignorant with the Holden six performance knowledge but very keen to do an old school hi-po street build too.

Picked up what looks to be a stage 4 head & a Cain 9 port with 13/4 HIF SU's for starters.

Looks like I could be under-gunned with the induction choice.

Not sure of the head compression & flow atm but it will dictate my cam selection.

Still a bit of a punter but builds like this certainly rattles my can. 

 

Cheers

 

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[I'm a Red Motor fiend]

Ando, that head looks like an excellent starting point.
For what you will need to put into those carbs though to get them up to scratch it might be worth trying to source some bigger ones and put the dollars into them?

[lakeside]

Some bigger pipes will help, my  300hp 202 hand grenade was running header pipes twice the size of what in picture above. 

[I'm a Red Motor fiend]

Some bigger pipes will help, my 300hp 202 hand grenade was running header pipes twice the size of what in picture above.

They are HM9C's, 1 and 5/8" primaries. Biggest and best you can get off the shelf. They will be adequate.

[LC-GTR-1969]

Some bigger pipes will help, my  300hp 202 hand grenade was running header pipes twice the size of what in picture above. 

 

My 202 is using HM9Cs and made 352hp- these pipes are good and should and I do not think they will be a restriction to this setup. 

Edited by LC-GTR-1969, 27 January 2020 - 03:14 PM.

[TK383]

Pipes are good, she just needs more fuel to the float bowls.

[LC-GTR-1969]

Any update on the engine? Would love to see the power curve... 

[I'm a Red Motor fiend]

Sigh, have been avoiding updating this but knew someone would ask.
Dyno session number two ended in disappointment.
Changed to grose needles and seats upped pressure to 5 psi. Thought we would be good to go.
Was marginally better but like before completely fell over past 5000 rpm.
Just too lean.
Running the UX needles still, clearly the profile isn't right as it is fat down low and mid but lean as up top.
Looks like I have the joy of needle polishing.
Could have left it on the dyno but can't keep having time away from my business so bit the bullet and took it off.
I have a lot of road testing and polishing ahead to get it right.

[I'm a Red Motor fiend]

Just realised we ended up with UL needles in there not UX.
UL have much the same profile but fatter up the top than UX but still no joy.

[LC-GTR-1969]

What springs are currently in the SUs?

 

Nearly all good 202s running 2 inch SUs I have seen love UP or UX, i'm surprised this setup didn't like it.. 

Edited by LC-GTR-1969, 15 February 2020 - 07:20 AM.

[I'm a Red Motor fiend]

So we used a go-pro to film the pistons each pull.
The 5oz springs enabled them to rise too early.
The 12oz springs just wouldn't allow them to rise fully even at upper rpm.
So we chopped down the 12oz springs a little more each pull till we got the pistons to fully rise.
When I get a chance I'm going to compress the springs on my scale to see where they're at. I'm guessing chopped down maybe 8-9oz?

[Heath]

How did the fuel bowl performance work with 5psi and the Grose needles & seats? 

I have a lot of trouble getting them to seal.
Very tempted to convert to a Holley fuel bowl.

[LC-GTR-1969]

So we used a go-pro to film the pistons each pull.
The 5oz springs enabled them to rise too early.
The 12oz springs just wouldn't allow them to rise fully even at upper rpm.
So we chopped down the 12oz springs a little more each pull till we got the pistons to fully rise.
When I get a chance I'm going to compress the springs on my scale to see where they're at. I'm guessing chopped down maybe 8-9oz?

 

I found I couldn't get the car to run well with 5oz springs. I ran 12oz and the AFR was excellent with UP needles. Never checked with a camera though whether they were opening fully. I also removed the dampers. 

[I'm a Red Motor fiend]

How did the fuel bowl performance work with 5psi and the Grose needles & seats?

I have a lot of trouble getting them to seal.
Very tempted to convert to a Holley fuel bowl.

Seamless transition really mate, no dramas at all, no leaks.

[I'm a Red Motor fiend]

I found I couldn't get the car to run well with 5oz springs. I ran 12oz and the AFR was excellent with UP needles. Never checked with a camera though whether they were opening fully. I also removed the dampers.

Yeah that's interesting, could be your pistons weren't opening fully and mine were hence the lean out where yours didn't??

When u say removed the dampers was this full time on the street no dampers?

[LC-GTR-1969]

Yeah that's interesting, could be your pistons weren't opening fully and mine were hence the lean out where yours didn't??

When u say removed the dampers was this full time on the street no dampers?

 

I thought yours were not opening fully with the 12oz springs? In honesty I have heard 2 inch SUs will have the damper rise fully but with extended run, ie dyno or long straight, the dampers start to drop down a little (so I have been told). Personally if the engine hits the hp goals I wouldn't worry to much about this but if you're already tuning and spending time on the dyno you may as well look into it...

 

I ran no dampers full time on the street, mainly for the improvement in throttle snap, quick response. They worked beautifully. When I ran dampers I used 3 in 1 general purpose oil, i'd say about 20 weight and car felt great but when I removed the dampers for a test I liked it so kept running without them. 

 

This was with a pretty radical cam with low manifold vacuum and lots of overlap, 266@50 on a 99lsa. Made 200hp at tyres. 

Edited by LC-GTR-1969, 16 February 2020 - 06:46 AM.

[LC-GTR-1969]

How did the fuel bowl performance work with 5psi and the Grose needles & seats? 

I have a lot of trouble getting them to seal.
Very tempted to convert to a Holley fuel bowl.

 

I had issues with my Grose needles at just 4psi, I had one not seal from factory, didn't believe it at first and started looking for every other reason for fuel bowl flooding but when I swapped it out issue was resolved. I think the vibration rattled the little ball and if the clearance was a bit on the sloppy side it leaked- well that was what I came up with. I researched a bit and it seems somewhat common so perhaps quality control is a bit of an issue with some of them. 

 

When the bad one was swapped out they ran great though. 

[greens nice]

I’ve found a slight tap with a hammer (gentle) on the gross valves can help just to Marr the seat together did the trick. The Seat may not have a perfect finish.

Also, the black nitrophyl ‘stay up’ floats are a blessing, they work well.

Holley bowl is too much drama IMO, and a lot of weight hanging off the side, naturally has a lot of fuel sloshing around in it too.
The factory bowl works good, but doesn’t hold much fuel because of how big the float is, not an issue on petrol but with alcohol and jet tube size nearing .160” the flaws show up. I added some volume to the side of the bowls.

[FNQ]

If your grose needle and seat is not providing enough flow at WOT, have you tried enlarging the feed holes in the side of the valve.? ( excuse improper naming). as suggested above regarding meeting the needs of Ethanol.- in my mind ideally you achieve extra volume without extra pressure. 

[claysummers]

Chuck those SUs in the bin........ 8)8)8)8)


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