So,

 

As the title suggests, I've set a target and I'm going tonshoot for it.

 

Picked up the Bready in Dec 23. It had an ABD fitted but was running on the 1.0 spi system. Took it to the dyno to see how it was running and surprisingly it was OK. Lambda sensor doing its job and sorting the fuelling. Result of running the 1.0 SPI was great low down torque but out of puff up top.

Played with the timing a little and settled on a better ifke abd 61bhp rather than another couple of bhp and a worse idle. Found out the cat was empty which probably helped a bit with the power/torque.

 

Now fitted the correct 1.3 SPI,  port matched the inleta little better, a 4-2-1 manifold and have some b2b testing to do on the manifold heater (hedgehog) removal.

 

Aside from this I acquired myself a piper bp300 cam, a spare ABD engine and have begun the strip down to see what's possible. No aftermarket internals available so looking at different options. Most likely current plan is to skim the pistons and deck the block by an equal amount to get the 9.5:1 CR up closer to 11:1. I'll also do some head work and look in to the possibility of larger valves (again nothing off the shelf). I'll add a set of itbs and standalone ecu and hopefully get somewhere near my target. 

 

The whole thing would be a lot simpler with the 1.3!!!

 

Some pics below.

 

 

 

 

Some back to back testing of modifications.

 

Dyno graph 1:

 

The lower line (72.31bhp/128.78nm)shows the first run in the spec I arrived with. That is a 1.4 ABD, using a 1.3 inlet/tb and SPI unit with a gravity 4-2-1. Everything else standard.

 

I then fitted the modded hedgehog (shown in pics) and went again. This picked up 5bhp & 5nm at peak buuuut......at some points it's +6bhp & 10nm(4k rpm)! As you can see from the graph it doesn't lose out anywhere.

 

Dyno graph 2:

 

The lower line shows where we ended up in graph 1. The higher line shows the same spec but now with my homemade induction kit added. Peak bhp almost exactly the same however......peak torque up by 4nm but more importantly, there are points we are +7nm (3250-3500rpm) getting rid of the slight dip in torque. You can also see it picks up 4bhp at the same rpm as the torque increase. As you can see from the graph it doesn't really lose out anywhere bar the tiniest crossover at 2250.

Quite surprising to me. Even more interesting was the fact that it actually helped the fuelling in the upper rpm range richening it up a tad. I'm guessing the air speed helping better combustion? Unsure of this but its the best reason I can currently think of.

 

Dyno graph 3:

 

This is the overlay of how I drove in, to how I drove out of the day. 

 

Dyno graph 4:

 

This shows the original 1.0 SPI system dyno vs the best combo of mods plus a tin of octane booster in the tank. I didn't get a graph print of with vs without octane booster but I did get the number table of all the graphs shown in no.5.

Picked up a couple bhp at points and up to 3nm. It seemed to be very consistent too once we'd let it run for a bit to mix it in. This I'm not bothered about I just had it so thought I may as well try it.

 

Disclaimer: actual numbers I'm not fussed by. 79bhp or 72bhp, one dyno will read different to the next. What I'm concerned with are gains. I used the sane dyno, same sainsburys premium fuel, same tyres/pressures and kept as much as I could exactly the same. 

 

Hope you've all found it useful. Can't wait to see all the bald hedgehogs now! 😆

 

Hit me up with any questions and I'll do my best to answer.

 

Peace

Edited 17 March, 20242 yr by BenGunn

Why did you trim down the pins that are inside the intake, does it improve airflow? And what is the point of those pins?

The pins cause turbulence in the intake air which aids in the mixing of fuel and air. Sometimes they are heated too, which improves fuel vapourisation when the engine is cold.

In a motorsport setup, is it better to remove them to reduce restriction, or keep them to improve the air–fuel mixture?

On 04/09/2025 at 21:19, yarne_l said:

In a motorsport setup, is it better to remove them to reduce restriction, or keep them to improve the air–fuel mixture?

Look at the dyno results above.

Nice work. Surprised at 0.5hp from the crank breather. I suppose a vacuum below the pistons would be good too.

The hedgehog heat effect turns off after coolant reaches 60°C or so. It's for cold start up running.

For race you want the best flowing pump and sufficient fuel to air at full load that no hotspots develop and melt the spark plugs or top of pistons. An octane booster helps reduce cylinder temperature. Using one heat range colder plugs does the same, but can be harder to start.

A mixture between 12.4 and 13.4 AFR usually gives max power. Depends on engine design and cam timings.