The Triumph Dolomite Club - Discussion Forum

The Number One Club for owners of Triumph's range of small saloons from the 1960s and 1970s.
It is currently Fri Mar 29, 2024 11:27 am

All times are UTC




Post new topic  Reply to topic  [ 5 posts ] 
Author Message
 Post subject: Rolling Road outcome
PostPosted: Sun May 29, 2022 4:45 pm 
Offline
TDC Member

Joined: Tue Jul 28, 2020 8:11 pm
Posts: 14
Thanks to all the help I have had from members and also gaining a lot of information from the forum.
Now that the engine (Sprint) is run in and going well I thought I would update on the outcome now it has had it's rolling road session.
The engine is as follows.
Nothing radical and pretty much standard as regards engine internals but the flywheel has been slightly lightened and crank etc. all balanced.
The camshaft fitted is a
Newman PH3 Fast road / Rally
290 duration
Valve lift 0.390 (9.9)
35 75 75 35
Twin Weber 45DCOE's with 36mm chokes
Jetted Mains 130, Air 160 and emulsion tubes F4.
Max Engine BHP 153 and 119 at the wheels at 5495. Power tailing off at 5500rpm.
Max torque 151 lbf ft at 5100 but pretty much a flat curve from 4200 to 5400rpm
Due to the fact I had points (not cheap Ebay ones) fail I fitted a left over Accuspark electronic ignition from a 1500 engine I used to have, optimal timimg was 28 degrees

So I'm really pleased with how it has turned out and look forward to having a blast!

Derek


Top
   
 Post subject: Re: Rolling Road outcome
PostPosted: Sun May 29, 2022 5:41 pm 
Offline
Future Club member hopefully!
Future Club member hopefully!
User avatar

Joined: Thu Oct 06, 2011 1:13 am
Posts: 3173
Location: The continent
The average Sprint has about 105 at the rearwheels so 119 is a big improvement. Unless the engine was out and on a dyno also the 153 engine power is a bit overexited.

Loosing 34 hp on the transmission would melt the alloy gearbox casing and you not being able to even tough the gearlever.. around 135 engine hp would be a more accurate figure when you have to guess something.

35hp loss are Landrover series figures with extra transfer cases and agricultural diffs.

Jeroen.

_________________
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com


Top
   
 Post subject: Re: Rolling Road outcome
PostPosted: Wed Jun 01, 2022 7:58 pm 
Offline
TDC Member

Joined: Tue Jul 28, 2020 8:11 pm
Posts: 14
Quote:
The average Sprint has about 105 at the rearwheels so 119 is a big improvement. Unless the engine was out and on a dyno also the 153 engine power is a bit overexited.

Loosing 34 hp on the transmission would melt the alloy gearbox casing and you not being able to even tough the gearlever.. around 135 engine hp would be a more accurate figure when you have to guess something.

35hp loss are Landrover series figures with extra transfer cases and agricultural diffs.

Jeroen.
The rolling road man has the loss down as "Drag Power" ? It is a newly rebuilt Sprint gearbox though, also has an LSD.
Wouldn't the transmission losses be more than 15 BHP?


Top
   
 Post subject: Re: Rolling Road outcome
PostPosted: Tue Jun 07, 2022 2:22 pm 
Offline
Future Club member hopefully!
Future Club member hopefully!
User avatar

Joined: Thu Oct 06, 2011 1:13 am
Posts: 3173
Location: The continent
You can measure the loss not totally accurate that way but it gives an indication. Running a negative dynorun where the dyno calculates how much hp it costs to 'run the transmission'. It should be done at full speed and then put the car in neutral and let it roll out to standstill.

At you car it shouldn't be near 34hp. I actually did 'measure' a landrover series this way after fitting a compressor and the loss was around 35hp at that car.

A healty Sprint should have a loss of around 15 hp with a max of 20. A faulty wheelbearing or play in an propshaft UJ can add 5+ hp to the loss measured on such a negative dynorun.

It isn't a fixed percentage as a lot do calculate their own 'must be' engine power. A 600 hp car loosing 20% by transmission....

A dyno is adjustable at many parameters and some adjust to the most positive. Enginebuilders who dynorun their own products have those habits the most. A high outcome does have the bill paid more easily by the customer.

When 34 hp loss at your car is the actual loss measured at a negative dynorun you should investigate where the loss is as when solving the cause there's a lot to gain at the wheels again..

Jeroen

_________________
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com


Top
   
 Post subject: Re: Rolling Road outcome
PostPosted: Sat Jun 25, 2022 5:36 pm 
Offline
TDC Member

Joined: Tue Jul 28, 2020 8:11 pm
Posts: 14
Quote:
You can measure the loss not totally accurate that way but it gives an indication. Running a negative dynorun where the dyno calculates how much hp it costs to 'run the transmission'. It should be done at full speed and then put the car in neutral and let it roll out to standstill.

At you car it shouldn't be near 34hp. I actually did 'measure' a landrover series this way after fitting a compressor and the loss was around 35hp at that car.

A healty Sprint should have a loss of around 15 hp with a max of 20. A faulty wheelbearing or play in an propshaft UJ can add 5+ hp to the loss measured on such a negative dynorun.

It isn't a fixed percentage as a lot do calculate their own 'must be' engine power. A 600 hp car loosing 20% by transmission....

A dyno is adjustable at many parameters and some adjust to the most positive. Enginebuilders who dynorun their own products have those habits the most. A high outcome does have the bill paid more easily by the customer.

When 34 hp loss at your car is the actual loss measured at a negative dynorun you should investigate where the loss is as when solving the cause there's a lot to gain at the wheels again..

Jeroen


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 5 posts ] 

All times are UTC


Who is online

Users browsing this forum: cliftyhanger and 31 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited