The Triumph Dolomite Club - Discussion Forum

They managed to match the BHP of Sprint, while not loosing mid range torque? I can well believe you can get high BHP from a small NA push rod engine on carbs but usually it involves making them worse to drive on the roads because you lose all the low down power.

Put it this way, those who mod 1300 A-series engines, similar to the Triumph lump, Reckon an engine putting out 120-130bhp would be hopeless as a road engine.

it is 10:1CR, big valve head,

Checking, I misremembered my head's CR and it's only 9:1. But which 1300 head casting and stamp number gives 10:1? I can't find one that does. Or has it been skimmed for the extra compression, and if so, by how much?

Graham

My PB in the Carledo (I have the time ticket in front of me, also from the Pod) is 16.014 @91.3mph, so your 15.8 is the more likely.

All my runs have been done on a stock SRi (130bhp) map which runs out of puff quickly after 4500rpm. I'm sure it's a mapping issue, the engine will rev to the ECU imposed limiter at 7200, but it loses interest noticeably after 4500. I reckon once it's mapped properly (a procedure i've been postponing for years) and maybe a size bigger injectors, an ET in the 14s is possible and perhaps even a TS of over 100. If I can get 14.5 or lower, i'll be a happy bunny.

Steve

My PB in the Carledo (I have the time ticket in front of me, also from the Pod) is 16.014 @91.3mph, so your 15.8 is the more likely.

All my runs have been done on a stock SRi (130bhp) map which runs out of puff quickly after 4500rpm. I'm sure it's a mapping issue, the engine will rev to the ECU imposed limiter at 7200, but it loses interest noticeably after 4500. I reckon once it's mapped properly (a procedure i've been postponing for years) and maybe a size bigger injectors, an ET in the 14s is possible and perhaps even a TS of over 100. If I can get 14.5 or lower, i'll be a happy bunny.

Steve

My car was running about 160bhp at the event, but as the "very good map" installed by the vendor, the cam/VVT timing was rubbish. Went to a mapper the day after, who cranked it to 175, but I discovered he also didn't play with the VVT. I have poked about, and reckon it is better now.

But the 1/4 mile is a very good test of a cars "power". Way better than a rolling road, 0-60 etc. As it is easy to fudge those numbers (A chap I know reckons swinging the cam can make a big difference to numbers, but no benefit in the real world) and I could improve 0-60 by changing tyre size. 1/4 mile means the car is REALLY tested.

so was mine 16.8 and then 15.8, or 15.8 and 14.8? not too worried. Std sierra cossie is 16.6/103, so slower but higher TS. Maybe I need more practice (very likely, I have only ever done 4 runs, 2 each year) and look at gearing. Saying that, I am not likely to visit the pod in the near future. A shame Madeira Drive in Brighton is so clagged up with bollards etc thesedays. (home of Brighton Speed Trials, and also an old favourite of the street drag racers back in the 70/80s)

[
A 15.8 @96 is believable, I think a 14.8 would give you a TS around 100-105. I'm only 0.2secs behind that, but my low TS is down to the shortage of top end power that I think was built into the factory map. The Sierra Cosworth time you mentioned is pretty anomalous in my experience, It feels like the driver wasn't getting it hooked up properly off the line, ie too much wheelspin! Or is that a 4WD Cossie? 4WD cars are known for bogging down on the launch.

I too have lost my happy hunting ground with the closure of Shakespeare County Raceway at Long Marston in 2017. Though oddly, the Carledo is always a couple of tenths quicker at the Pod. Perhaps the surface is better, also there is (or was) a prevailing headwind at Shakey since it was a disused runway.

It may sound counter intuitive, but try running with some extra weight in the boot, it helps with traction off the line. I also run the front tyres at 40psi to reduce rolling resistance and the rears at 12psi which again helps with the launch. Gearing is not so much of an issue, it's swings and roundabouts, a 4.11 will get you off the line a bit quicker, but it will promote more wheelspin in a light car and also might necessitate an extra (time sapping) gearshift further up the strip. So I stick to my economical roadgoing 3.45. Mostly, unless you miss a gear or something equally daft, a drag race is won or lost on the start line. Therefore a good time is all about a good launch. But yes, practice helps - a lot! I've been running quarters since the early 70s, still get a big kick out of it, even though my car PBs are not what they were, my old pro comp 390 '61 Galaxie, with 450+bhp would get me into the low 11s @120+.

There was a guy I used to come up against a lot at Shakey on RWYB days. A very clean and professionally turned out MkI cortina 2 door with a Zetec in it, he'd just roll onto the strip, brief linelock burnout and ease it off the line to a very consistent and apparently effortless 14.5 @107 or thereabouts. That's kinda the benchmark i'm aiming for with the Carledo. It's also pretty much why I haven't run much lately, there's not any realistic amount of time to be gained from messing about with weight and tyre pressures any more, the car is about right as is, I need more power to go faster! Until I have some, it's just a bit frustrating, being THAT close to a 15!

Steve

I like Butler-Henderson's description (of the Range Rover): "all the aerodynamics of a sub post-office".