Alpine Chassis Dyno pulls

[spmdr]

Seeing I can't find any Chassis Dyno Threads, I'll start one.

(Edit- another thread here http://forum.sunbeamalpine.org/index.php?threads/dyno-testing.13337/)

And seeing the one I have handy is from a Vintage Race Alpine, I'll put it in the Racing section.

BUT, I'd like to see Stock Alpine Pulls as well.

Note the TQ and HP scales are not the same.

It's from 2004 and not the biggest ball of fire pull, but a starting point.

DW

 

[spmdr]

On the web I found this dyno test of an Alpine and two Tigers.

Note the Black smoke coming from the Alpine at the end of the run.

Bottom line:

Alpine 50 WHP
Stock Tiger 74 WHP ( a LOW number for a Tiger!)
347 Tiger 350 WHP



DW

 

[alpine_64]

Dan.. Jim E (old forum member) used to run a fairly warm 1725... 2x40dcoe holbay carbs on a warnerford gooseneck, delta grind ( one above KB... Something 9?) Flat tops and a vizard heax woth 3 angle and stock valves. Chrv rods and flat tops.

Iirc it put down 86 RWHP...and that was a fast fine.

 

[alpine_64]

Dan,

Here is the old dyno sheet from my 1592 race motor on twin SU carbs... Flat tops, ported. Big valves cam headers roller rockers .060 overbore manley chev rods.

Figure was to the wheels not adjusted etc. 104.4hp

 

[Warren]

That YouTube of the Alpine and Tiger is laughable. The barn find Tiger was a let's do nothing to this motor and see if we can blow it up. But in all fairness I've seen guys show up at a club Dyno day with old gas in the car and say doh...

 

[Bill Blue]

As I recall, Jim Ellis also reported the indignity of producing about 50 hp in a stock 1725. While he would have been happy with less than 100, less than 75 was more than he could stand. His only comfort, the dyno operator said that 50 hp was very common among engines of that size and era.

Bill

 

[spmdr]

Thanks Michael.

Question- what rear end gear was your Alpine run with?

You make a Great case for 1600s! I'm looking REAL close at my next Alpine VR

engine being a 1600.

BTW, "...fast fine" ??


The dyno pulls above (post#1) were done with 3rd and 4th gears, and the curious dip in the TQ curve is a bit of a mystery.

I'm not sure of the rear end gear, because 3rd gear was used, I don't think it was the 4.55


Yes, it's a bit of a challenge to come from the Sunbeam Tiger VR world where power

is more of a liability and FAR from the biggest problem.


Then enter the Alpine VR world and be at the bottom of the power scale,

and have THAT be the Biggest problem.

I have a lot of Alpine info to catch up on, I was Busy WASTING my time playing with Tigers....?

 

[spmdr]

The Tiger club CAT did a short scheduled Dyno day, so I took the WR Alpine.

This is the same short block as ran in post 1 above, with a different head, different induction and open exhaust (early Tri-Y).

The current head is a STOCK SV head with stiffer springs, gee how much GAIN was the original BIG valve modified head?

...the case HAS been made, ZERO.... or very little. Hmmmmm (some serious head scratching (pun intended) going on)

The induction was changed from 30 mm to 34 mm chokes, in the 40 DCOE 151s, clearly, they are not fully sorted as seen by the first run going way lean with the throttle opened too fast.

Also, on the last run, I thought I could detect the sound of valve float, explains a bit!



I'll re-post the first run for easier comparison, note different scales.

 

[alpine_64]

Dan,

Are these rwhp figures? Are they temp corrected or straight shootout mode?

The new motor appears to have around 6hp on the old.. In a motor sub 100hp.. Thats a decent increase as a %... But given the work you are doing etc. Not where you want to be.

If the original dyno sheet for steves was a big valve head 1725 on 2 x dcoe. . id suggest the motor had some fundamental issues.. Be it cam.. Chamber shape doing something restricting effective flow of gases out the exhuast... Or....

 

[jdoclogan]

"The current head is a STOCK SV head with stiffer springs, gee how much GAIN was the original BIG valve modified head?

...the case HAS been made, ZERO.... or very little. Hmmmmm (some serious head scratching (pun intended) going on)"

Dan, I've returned to Alpine race engine builds and reread all of my materials the last few days. In the December 2001 issue of Practical Classics under the Modified Classics section the author, Mark Dixon, noted in his article Alpine Horn, "Bigger valves have been fitted to the head, although there's not a lot to be gained from fitting bigger valves to a standard 1725 because they will be shrouded by the cylinder wall, negating any potential advantage." Your test apparently confirms the notion that bigger valve better flow isn't necessarily true. Did the head undergo a Vizard modification?

As for valve springs - Doanne Spencer incorporated stock outer springs with competition inner springs to attain an on seat pressure of 82 pounds. This was based on the G-cam incorporated 29/65/65/29 ( Sports Car Graphics, Sept, 1962). Below is the 1962 dyno results from Project Sunbeam. Note: Peak torque of 109 lbs/ft at 4000 rpms.

 

[spmdr]

Jerry, GREAT Old Dyno stuff! Of course, in '62, NOT a 1725.

AND, not likely a Chassis Dyno pull , BUT an Engine Dyno.

We DO need to keep the Dyno Type Noted, because of the difference.

I'm not sure of Alpine numbers, but Tiger power range Engine Dyno to Chassis Dyno conversion is about 18% less.

And then, looking at Dyno graphs that have different scales is a challenge.


The original Big valve head Does have a Mod to un-shroud the valves, but Clearly, it LOOKS better than it works.

....And/or the head has other problems...

But the SAGE Head Guy has it and will Tune it UP when he recovers from a Quad By-pass.

Of course, NOW I want to see the NEW Big valve head results More than ever!!

 

[spmdr]

Steve Alcala did some house cleaning and found some old dyno info.

Dated 1994.

Some details:

AEM Dyno Compton, CA

1725+.040, flat top forged pistons, ported and milled head, reground cam, early stock Tri-Y headers.
Custom intake manifold.

-started with 40 DCOEs with 28mm chokes Max 82 HP @ 5500
100m 190ac F16 ...timing 14I -34 total

-ended with 30mm chokes and 91 HP @6000
120m 170ac F11...timing 11I -32 total

too bad bigger chokes were not tried.

Interesting, back then they used mainly CO% to determine mixture.

My weak memory had the last thing changed was emulation tubes.

I thought it was from F11 to F16, but the docs suggest the other way,

even though later docs have F16 in the carbs.... Hmmmm.

DW

 

[GlennB]

This was the result with my 1600 engine, straight from a new build with DCOE's and 30mm chokes. I reduced my Silverstone short circuit laptime down from 1:32 to 1:28 when I installed 32mm chokes. Sadly the rolling road went bust during Covid and I haven't been able to repeat the test. I'd like to think there's a few more horses now I've changed the chokes and put 2000 miles on the engine. The 30mm chokes were definitely hurting the high rev performance. The car was previously rallied and needed low range torque.

 

[spmdr]

Recently, our best priced Go-to Dyno place closed also, ...not do to covid so much....

So future dyno runs are in question.

We may have to resort to some APP on our phones??

...if anyone knows of an APP, do tell...

BTW GlennB, can you run a BIGGER Weber, like 45s?

(see other carb stuff: )

https://forum.sunbeamalpine.org/index.php?threads/weber-40-dcoe-mods-for-more-flow.30747/

DW

 

[alpine_64]

View attachment 28841
This was the result with my 1600 engine, straight from a new build with DCOE's and 30mm chokes. I reduced my Silverstone short circuit laptime down from 1:32 to 1:28 when I installed 32mm chokes. Sadly the rolling road went bust during Covid and I haven't been able to repeat the test. I'd like to think there's a few more horses now I've changed the chokes and put 2000 miles on the engine. The 30mm chokes were definitely hurting the high rev performance. The car was previously rallied and needed low range torque.

Glen,

Are these RWhp ?

Engine should have loosened up a little since your first pull.

Iirc Chris Draycott is selling track motors over there 1725 based on DCOE's with 150ish HP? Assuming flywheel HP.

 

[GlennB]

I'm sure this is power at the wheels. It is a Chris Draycott engine with all the tweaks. I witnessed his own personal 1725cc engine in action when he beat half the Tigers in the 2014 Sunbeam Challenge so I don't doubt the claimed power. I stayed with 1600cc so I could stay in spec for my favourite historic series. I'm stuck with the 40's for budget reasons and as for increasing the choke size further I think that this would need rolling road sessions and then probably find that my exhaust bore is then the constraint - that was Chris's opinion some time back. It's all about air flow and something stops me going much beyond 6KRPM. Jerry's been in my car with this 1600cc engine and can vouch for it's liveliness. At the moment I am running in a road-going 1725cc to make it easier to drive to this years various shows and meetings.

 

[spmdr]

The Tiger Club (CAT) found a New Chassis Dyno place.

I took the WR Alpine to their new location.

It turns out the new location has a very recent NEW Dyno,

it is only 2 years old.

Both old and new Dyno shops use DynoJet Dynos

So, in theory, all should be good...


The first car on the Dyno ran at the old Dyno place,

it pulled a 239 WHP.

At the new place the first pull was a 219 WHP, not quite what was expected.


One definite difference in the old and new location is the elevation.

The old location was better at only about 100 ft above sea level.

The new location is 900+ ft above sea level.


The second Tiger pulled a lower than expected number also.

The WR Alpine ran third.

The only Alpine engine parts that ran the last Dyno location are the exhaust

system, (but this time with the muffler) and intake manifold.

The new engine has more Cam, bigger exhaust valves, bigger carbs and an MSD ignition, but less compression.

I expected maybe 10 more WHP if run at the old location.

At the new location, my expectations were quickly going down....

The first pull had the engine missing at the top end and shut down a little early.

However, it pulled 99.20 WHP @ 5,680 RPM and 101.36 ftlbs @ 4,590 RPM.

All was not lost.

The second pull ran better but was not run up to the rev limiter of 7000 RPM.

Maybe 6,100 RPM was as high as it turned.

The second pull was 103.32 WHP @ 5,770 RPM and 103.68 ftlbs @ 4,560 RPM.

I attribute some of the difference to putting a little heat in the engine oil,

even though I tried to warm up the Alpine, I got little heat into the oil

by the time of the first pull.

Here is the printout they gave me:




A bit hard to see any details.

After all the runs, I asked them for a higher res printout:

 

[alpine_64]

Dan,

Interesting results ... and good. It is intesting you have a drop in power around 5500 before it climbs again before hitting peak before 6.. was that ignition or fueling causing the dip?
this is with your modified Weber chokes . Did you signle side the anular or still supported across the choke?
in theory you are running around 110 +/- rwhp elevation corrected.. strong... This is the 1592 long rod modern piston motor?
I'll drop you an email with more geeky questions ..
a video snuck from CAT of the weekend racer singing

2024-0316 cat dyno day - weekend racer alpine

• alpine_64
• Mar 17, 2024

Dan W dyno run

2024-0316 cat dyno day - weekend racer alpine

Dan W dyno run

forum.sunbeamalpine.org

 

[spmdr]

The current engine is Alcala's second 1725.

With the recent MSD 6AL box, it has the "soft touch" rev limiter

that drops alternate cylinders and sounds like a miss.

Even though at a low RPM, that is what it sounded like on the first pull.

...but was not the rev limiter.

I had let the Alpine idle for quite some time to try and get some heat

into the engine, so the carbs may have been unusually warm on that first pull.

The second pull sounded clean, but the Dyno print out showed ....

a lot of Work to be done, yet...

I brought the open exhaust pipe but the shop was happy to not see it on the car.

The few residents near by were likely just as happy.

I left the jetting as it was run last with the 135 mains.

You can hear the 45 DCOE carbs are working quite well, with good throttle responds.

As the print out shows, it did go a little lean at the higher RPMs.

.....CLEARLY, I was giving away MASSIVE amounts of Power..... he tells him self....

DW

 

[spmdr]

Easier to see.
MPH instead of RPM.