Bit of help needed if possible.
With a bit of decent headwork on a 9 port Hi comp head & the right cam in a 202, what is the approx upper limit of HP expected from a set of 1 3/4 SUs @ the flywheel?
Posted 26 April 2022 - 02:48 PM
Bit of help needed if possible.
With a bit of decent headwork on a 9 port Hi comp head & the right cam in a 202, what is the approx upper limit of HP expected from a set of 1 3/4 SUs @ the flywheel?
Posted 26 April 2022 - 03:45 PM
Posted 26 April 2022 - 07:41 PM
Thanks for that Bruiser.
Id like to acheive around 250+ at the flywheel & have seen 265+ from an engine on youtube by powerhouse engines, it sports a small 4bbl holley & they mention alot more would be possible with a set of triples, but i guess he aint talking about 1.75 SUs
Any feeback would be apreciated
Posted 26 April 2022 - 10:34 PM
3x 1 3/4" carbs can potentially flow 624cfm. If I get a chance tomorrow I'll run the numbers.
Posted 27 April 2022 - 11:24 AM
Would appreciate that.
I have read the carbies will support around 200 cfm each, but what figures have actually been produced on a 202 with a decent 9 port head & cam, say to max 7000 RPM with them.
Most have gone 2'', but im not chasing 300HP.
Would just like to know what real world figures members have got, using HS6 1 3/4 SUs, or am I wasting my time with 1 3/4 triples trying to chase 250+ HP with them & maybe i need to look at other options?
Posted 27 April 2022 - 01:49 PM
Posted 27 April 2022 - 03:54 PM
Posted 27 April 2022 - 04:41 PM
Yes Adam carbs on a working red 202 in my LJ, but have come across a virgin blue motor Block with crank & rods to play with. , just trying to keep costs down.
Bruiser, sounds like 250 could be the limit with them then.
You would think 600 CFM could support more power?
it would be interesting to hear of anyone else's experiences?
Posted 27 April 2022 - 05:24 PM
Posted 27 April 2022 - 05:29 PM
Posted 27 April 2022 - 05:49 PM
Posted 27 April 2022 - 08:05 PM
Well Lets Say Constant 6500rpm changes and redline 7000!(spoke to HSD in Melb for head work on my old yella 6000 head)
The red in it now was put together in 1985 & it still has no probs reving to 6k(and this car sat idle from 1992 til 2019) but its leaking a fair bit of oil, so time to pull it out for a refresh or the blue motor build!!!!!!
Bruiser, great minds think alike, I reckon the triples should perform better than the holley as well???
Posted 27 April 2022 - 10:40 PM
That 624cfm is [email protected]", can't remember if the 600 Holley is measured at 1.5" or 3".
Posted 28 April 2022 - 05:02 AM
Posted 28 April 2022 - 09:17 AM
Thats what im Hoping for 250 plus if possible.
Talking about holleys below.
http://www.gmh-toran...carby/?p=878142
4bbls measured at 1.5.
Posted 28 April 2022 - 11:31 AM
Thanks Warren, if you can make 260hp with the 390cfm holley, I cant see why you shouldnt get a little more with 624cfm from triple 1 3/4 SUs.
Hopefully we might get some feedback from someone that had a bit more experience using those carbies.
Posted 28 April 2022 - 05:08 PM
Posted 28 April 2022 - 07:17 PM
I better stop there then bruiser B4 i embarass myself anymore.
Just love these little engines & want to make sure the package I put together 35 yrs after the last one. is going to do the little six justice.
Thought some of the fellas might have had dyno figures over the yrs of where 1 3/4 finish & whether the investment or search would be validated in HP to chase a 2'' option.
This thing will be driven on the street.
Any help or guidance would be appeciated.
Posted 28 April 2022 - 08:12 PM
Posted 28 April 2022 - 08:33 PM
Posted 28 April 2022 - 10:04 PM
Awesome question Bruiser.
The 1 3/4 & old 70/30 watson in the car ATM, behaves quite well on the street & to be honest since giving the old girl some xtra spark & paying attention to to the advance curve it runs far better than it did back in the day, and its fun to drive(makes me smile, but no idea of HP, a guess of 180@ flywheel)
So knowing how the 2'' behaves in the higher HP six, would be nice, do they help it behave better at lower RPMs as well?
Adam,
Thanks for your help,
I have a M22 box & 3.08 diff which i will fitt, so around 2750 RPM @ 100Kmh, so your right, no good having a cam that doesnt come on to 3000!
Head is an old HC 173 Yella bathurst 6000(HSD in melb have quoted to bring it up to 250-300 HP flow rates).
No cam chosen yet but,
HSD Have mentioned a Crow XU1 cam to get the HP mentioned, had a bit of a check & it seems those grinds are hydraulic.
I was thinking more solid cam, as I was going for yella terra adjutable joined roller rockers, to get away from the hyd setup.
Any suggestions, would be appreciated.
So if i was going to spend some Xtra dollars on 2" carbies would I be better to go down the HSR path??, or is that too much of a race option?
Posted 29 April 2022 - 10:06 AM
Posted 29 April 2022 - 01:34 PM
Thanks Bruiser.
Ill give those blokes a call, solid seems to be the way to go now(read Oldjohnno's invaluable pages any times, excellent information)
Never had any probs with hyd, but rarely took my old motor past 6000.
Thought pattern originally was, If HSD in Melb would build the head, he could match cam choice to headwork, or is that not how its done?
Had read a bit about the HSR thing & thought it may be a tad easier to get a hold of & cheaper(was thinking I might also get away the old LYNX manifold as they talk 38-42 mm HSRs & hoped they might fit on it with some work)
I think 2'' SUs and a manifold are gunna be hard to find today?
Or just build the engine with better carbs in mind, use what ive got & see how it goes?
Posted 29 April 2022 - 02:10 PM
Posted 29 April 2022 - 04:38 PM
Virtual Cheers to All, thanks for your help.
Appreciated!
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