A BIT OF SIL 175 TUNING

[Darrell Taylor]

Moving on from a bit of sil 200 tuning heres the small block 175 kit tuning

starting out with a 175 kit with mahle piston complete with head and gaskets at around £120
this makes a low cost kit ,obviously tuning on top bumps the price up

the tune was pretty much the same as the sil 200 images in my other post and port widths kept very safe for the rings used

the rest of the set up was a 26mm dellorto carb on an unmatched inlet manifold tested a few pipes but nk rally pipe showed best results,the rest of the motor is standard
with the final set up as dyno graph running on 11-1 afr
keeping the port timings low has given it an early peak at 6k but a second peak at 7500

a peak over 16bhp and tq over 14ft lbs from std 175 engine components

has a wide spread over 14bhp+ from 5.5 to 8k 2500rpm wide

[CANbus]

I'm a fan of your work Darrell
Whats the SAE standard correction factor all about?

[drunkmunkey6969]

starting out with a 175 kit with mahle piston complete with head and gaskets at around £120
this makes a low cost kit ,obviously tuning on top bumps the price up

Great result Darrell....classic example of what we call 'Bang for Buck'! We love doing these old school tunes.

My only reservation when discussing these with customers, is the 'false economy' caveat....by that I mean it makes sense if they already own/run a 150/175 kit and want some 'bang for buck' tuning. I cant fault it then. But I don't think it makes sense to buy this kit specifically to be tuned. Do you?

Can you outline what the cost of this porting/tuning job might be if a customer wanted the same doing to their existing kit, so forum members have a price guide to accompany the graph? (Not including pipes and dynos, just the porting/machining work etc). I don't know what you would charge, but i'd hazard a guess the cost of the kit, plus porting/tuning etc would start moving the cost more than half way towards a little GT or Mugello 186 kit for example would it?

So I think that in the long-term, the costs quoted plus an extra bung, would be better spent on a new kit. Just my humble opinion like, not everyone will agree. But I think its the same when people go out to buy a Rapido kit looking for cheap power, then they buy a reed valve kit, then they get it ported, and then they have.............TS1/RB power? lol I'd just buy the TS1/RB kit to begin with......unless of course (as already said) you have an existing Rapido/Cast Iron kit running.....then the porting/tuning can make financial sense.

Bang for buck!!

[Darrell Taylor]

heres pipe tests

bang for buck really good on one of the graphs below shows it with a sterling pipe fitted in blue that performs really well

175 kit £120
tuning £120 (4 x ports cast iron) i price tuning on time taken eg a 11 port rb in alloy takes much longer than a 4 port mugello in alloy ,ive not bothered with pricing or adverts on here as im always 6 months behind so dont want to let people down
sterling pipe £60


red nk rally
blue sterling
purple jl4 curly
green pm25 ev

[Darrell Taylor]

I'm a fan of your work Darrell
Whats the SAE standard correction factor all about?

the sae correction puts mine and dans dyno into dynojet equivalent results but the 0.976 or so you see at the end moves around based on the weather station input or probe results factoring in performance changes from improved or worser conditions for power production 1.00 is uncorrected

some grand prix teams run uncorrected all the time but run an air conditioned/temp controlled dyno cell

[hendy]

What are the port durations on this barrel, or is that a secret? I'm having go myself and am thinking 126 transfers, 172 exhaust and about 140 inlet.

[Adam_Winstone]

Good thread

[HotPearlSnatch]

a peak over 16bhp and tq over 14ft lbs from std 175 engine components

Darrell that is way cool, if i am not mistaken the first batch of TS1s were coming in at around 16 bhp, this is a significant figure for a 175 motor. Kudos to you and many thanks for sharing.