Power limit on charger

[Karlos the jackyl]

I've got an Aldon graph of Barney's hitting 185bhp too somewhere. Alan's 1341cc made similar numbers at Aldon too. Didn't think Barney came to that Stealth day that Karlos organised back in the day?

Name: Barney Smith

Reg: J8

Modifications: G40 1341

Estimated Power: n/a

Actual Power (BHP): 194@7699

Actual Torque: 159@4241

Operator Comments:  Low down pinking . however very good power

Owners Comments:  Ditto

[Karlos the jackyl]

I do know barneys was the one of the first 1341's and had lots of development time put into it.  The results show this.

[Andy]

I stand corrected!

The plot I've got of Barney's car is 181bhp at Aldon - just checked, it's a bit wiggly though so I assume it might've been pre-mapping etc.

Note the high rpm at which it makes the power, I think this is why the over-square 1341cc cars seem to just pip the 1473cc motors in the power stakes; as they're willing to rev.

[Karlos the jackyl]

I cant remember if stealth was after or before aldon  but I remember the power was linear to the red line.  I was very surprised to see rev so high. Those sort of revs usually warrants solid lifters

Even if the stealth  rollers are dyno day figure happy it was really good to compare all the cars on the day .

I firmly believe the 1473cc hasn't been fully exploited... yet

The 1341's took time to start making the numbers and the 1473cc are in the same phase.... They are easily 250- 300hp engines

For example PUTO_T40  is using larger CC's  (1391cc block by his words)  and passing @124mph ... this is not your usual 220hp car.

[polo classic]

I belive the 1473cc's really need bigger valves, both exhaust and inlet. Thats why I'm going 38/33, but 37/32 might be more reliable.

On the 1473's, I think you also are on the edge of what the 3F manifold can do well.

I'm fairly sure my 1473 will sport a different plenum

[z3i]

I belive the 1473cc's really need bigger valves, both exhaust and inlet. Thats why I'm going 38/33, but 37/32 might be more reliable.

On the 1473's, I think you also are on the edge of what the 3F manifold can do well.

I'm fairly sure my 1473 will sport a different plenum

are you going turbo? this will be rather interesting should start a thread on it
like people say, just dont think there is enough research into the 1473cc i bet there was a shed load of trial and error in the 1341 when people first started doing it
1341 is probably the limit on other things as you say valve size, inlet mani size etc

[RyanC]

The thing is putting bigger valves in both inlet and exhaust means ur making the gap very small between the valves makeing it a lot Easyer for the head to crack!
I have seen on German eBay some "rs" inlet manifolds that have been made from scratch and are a lot bigger than gt inlet but they cost a bomb and they never pop up.

[Nick_S]

The right cam is going to be a big factor on the 1473 to unlock the power. I remember curries old motor, sister engine to mine bar the cam, made a lot less power than my schrick'd one.

[polo classic]

I belive the 1473cc's really need bigger valves, both exhaust and inlet. Thats why I'm going 38/33, but 37/32 might be more reliable.

On the 1473's, I think you also are on the edge of what the 3F manifold can do well.

I'm fairly sure my 1473 will sport a different plenum

are you going turbo? this will be rather interesting should start a thread on it
like people say, just dont think there is enough research into the 1473cc i bet there was a shed load of trial and error in the 1341 when people first started doing it
1341 is probably the limit on other things as you say valve size, inlet mani size etc

The basic spec is as following
1W block
JE 77mm 8,5:1 cr
Knobloch Sport 38/33 BVH (I think I have posted some pics here)
Rothe exhaust manifold
PSD Intercooler
PSD downpipe

For starters I will use a GT cam, K03 turbo and 3F manifold and early PSD 49.5 mm TB
When I have mapped it ok, I will change to either a K04-15 or a Frankenturbo type turbo and try to have plenum made up with sufficiently large volume. The cam will certainly be better than the one I have now, but I think I can get away with at least the same duration and a bit more lift. The mildest lobe on some of the PSD cams are 276 degrees

For the 38/33 mm valve combo to work, you need need offset valve guides. I also belive the bigger bore helps the head "live", more surfarce are for the heat to "cling" to, for the lack of better technical words

[RyanC]

Ahh I see, seems like you got it all worked out will be interesting to see what it will produce!

[RyanC]

Got any pics of the head mate? I had a quick look but can't find any

[polo classic]

[RyanC]

That's awesome man! How do u offset the guides? I can't get my head round how it would be done!

[polo classic]

[z3i]

That is crazy!! Bet it all cost a pretty penny!
SBVH super big valve head