Power and rev limiter

[RobertC]

I recently bought a 1993 SE powered by a 2.1 pinto engine. Car has had a full service including cambelt change and my mechanic thought the engine was performing as it should.

I have a roling road power diagnostic for the car from a couple of years ago that shows 153bhp engine output and 105bhp wheel ouput. The car has only done a couple of thousand miles since then.

Took the car on the track for the first time this week, and it just doesn't feel as quick as I expected. It drives well and is pretty competitive through the twisty bits, but I am just not getting the pull I expected accelerating out of a bend - this is where it feels uncompetitive. I am comparing this to a 150bhp Elise series 1 I used to track regularly that realy pulled out of a bend.

So some questions. Is 153bhp about right for this engine? I know it is hard to say, but should I be getting more pull than I am getting from a SE with this engine? Other Westie's with more modern Ford engines, but running the same or less bhp, were noticeably quicker. I appreciate the pinto lump is a bit heavier than the more modern units.

The car has a Speed System rev limiter fitted. Is this normal? Could this be having some effect on the performance? It is set at 6000rpm limit.

Assuming that the bhp I am getting is about right, what should I be doing to get more out if this engine. I would really appreciate your thoughts and advice. I really like to car, and I wouldn't rule out an engine swap if that is the only way I am going to get the performance I want, but would like to explore what is possible with this unit first.

Robert

[john_margaret]

Hi Robert,

I'd say the flywheel hp is about right for your car, think SE sell 2.1 trackday pinto's at 160hp, and these would be fresher.

I'm assuming you don't have any radical cams and are proabibly running 45's with 36mm chokes.

Pinto's thrive on revs being only 8 valvers with quite radical cams out of the box, I'd say that a safe rev max would be 6500. Think conrods are a weak point so more money spent tuning would in my opinion be a waste considering you can get new 2ltr zetec's for <£600 with maybe another £200 for fitting/water pumps/new manifold etc.

If going Zetec you should end up with slightly more power and a far fatter torque curve which will give you the drive out of corners. (Although Duratec would keep the exhaust on the correct side )

P.s. the difference in flywheel/wheel hp is quite alarming.

[ban1216]

That is an a lot of power loss in the drive train !!

what does the car tick over like will it idle nice and smooth or is it really lumpy and needs a high tickover

Also if is a 2.1 pinto they are very sensitive to cam timing and need to be set up by somebody who knows old skool motors to get the best out of them

[Cleggy the Spyder Man]

the only way is to get it to a rolling road as you have no knowleadge of how the car should feel

you could mess around with compression tests and try tuning yourself but unless you really know what your doing

A few more specs of the car would also help to see how your car compares to other westies on the track - they could well have been track day monsters with super grippy tyres, good drivers, very light cars etc etc

If yours is a standard road set-up car with std road type tyres they will scream away from you

did you enjoy your day though?  

[Matt Seabrook]

If the cam belt has been replaced has it been timed correctly performance cams need different timing settings.

[pistonbroke]

apart from power output there are other major factors you should consider  that would effect acceleration

can check these :-

gear box type and ratios ?

diff ratio / lsd type ?

standard flywheel or lightened

tyre / wheel sizes / diameter

[Blatman]

Make sure you're getting full throttle. You wouldn't be the first person to have suffered with a "slow" car, only to discover that adjusting the throttle cable is all that was needed.

I also agree that 50bhp losses through the transmission seems lke a lot...

[markcoopers]

From following a burgudy pinto powered car in these parts, it is not the revs that make it fly, but the massive tourque. That said it does require a different style to an Elise, as that would be all about revs for the 150bhp, the 2.1pinto is not.....perhaps a higher gear on exit would ellisit a much better effect?

As Blatters say....full throttle?

If you are to throw money at the engine, i would advise finding an already modified pinto, as it will be a cheaper route and simply swap over. And as tempting as an £800 zetec conversion sounds, add another £1000 to this for all the fluids, the ECU and the time on the Rolling Road you will need to get it all working well.....and from experience will only give similar bhp but lower tourque.

If it were my cash, i would start with the gearbox.

[RobertC]

Thanks guys for all your helpful comments. I really appreciate it. It's so hard to judge yourself when you have no experience of the car.

By the way, I absolutely loved my first experience with it on the track. So much more intense and direct than the Elise. And that's coming from a die-hard Lotus fan!

I like torquey engines so, on balance, I am going to explore the loss of power at the wheels before I think further about an engine swap. I plan to take it to Ric Wood at Stockport where he can rolling road it and see whats up and what needs to be done to get maximum performance from what I have.

I'll post the results shortly.

Robert

[John Loudon - Sponsorship Liaison]

Take the handbrake off  

[Robbie Rotten]

ric is very good  he will sort it out!!

[combatsapph]

Nothing really to add but an engine that makes 135bhp at the flywheel will make about 105bhp at the wheels in a rwd setup.

[Firestick]

It depends what state of tune the engine is in and as mentioned above how well it is set up.

My Pinto is rated at 152 bhp and 150 lbs at the wheels and has been built an set up by a specialist with regular tuning and she thumps out of the corners.

Basically preparation is everything.

[bultacobarry]

105bhp at the rear wheels sounds about right for a standard pinto with a cam and a set of webers bolted to it. I ran my westie in this spec for about a year and it felt pretty 'breathless' above 5500rpm and died a slow painful death in hillclimbs using the higher gears.  

A 'group one' head and a more radical cam brought it to more like 130 at the wheels and in combination with a diff change, lightened flywheel and close ratio gearbox really brough the car alive. I would expect that a pinto should have a rev limit more like 6500rpm than 6000rpm. My current pinto has the limiter set at 7,800rpm and makes max power at 7,300rpm.

[markcoopers]

And there is not much of it left at 7,801rpm