Penta heads

[jtbo]

On ITBs? They won't be cheap either! The stock B200/B230 TB won't flow enough air NA to make as much as 40s will, pound for pound A 960 (or some big yankee stuff) TB swap might be interesting!

cheers

James

In NA engine 150-160hp max was stock injection throttle body that I had also, diameter is bit small.

In some redblocks there is bigger throttle plate, but that had 4 bolt pattern where ours is 3 bolt pattern, adapter plate is not very easy to make for that either, imo.

[foggyjames]

That'd be from a K-Jet manifold, I presume. Do you have any specs on what was done to extract 160-170? Kev Strong got to about 140 IIRC...that was with a VX3 cam (probably not really toppy enough for high peak hp figures), revving out to 7000-7500, and an exhaust...plus a port'n'polish.

cheers

James

[jtbo]

Here is calculator for throttle body size and hp, it is in section throttle bodies.
http://www.megamanual.com/v22manual/minj.htm

Stock injectors top around 150 too if I don't remember wrong, so going above that it will cost bit more, around same as carb setup I would say, perhaps even more if buying all new from some tuning shop (they rip you off)

Putting K-cam and good exhaust manifold takes pretty much everything out that you can except from stock injectors + throttle plate, that is conclusion I made when testing and calculating things, that was over year ago so it can be that I have mixed something again in my brain, but use calculators on that page, there should be calculator for injectors too.

[foggyjames]

That sounds pretty logical Jani

cheers

James

[Carl]

I'm not convinced about MS, well more accurately I'm not convinced I could get MS running. Besides, there's something kinda nostalgic and 'right' about having a oldish car running a couple of gert big carbs. I've always wanted to do it and the 360 seems the ideal car to use them in.

I know someone that may be able to help with the manifold, at the very least he'll be able to sort the rest of the exhaust. In the meantime I'll be on the lookout for other cheap bits (ie carbs and manifold!!) and also taking the engine apart to inspect it and renew all the seals/gaskets.

[jtbo]

One thing I don't get it why twin carb manifolds do cost so insane amount of money, typically 200-300€ here?

That is just few tubes welded to machined plates, would think that 50 would be more like in proper range?

But then again I don't get it how ITBs can cost 800€ or even more, 100€ tops, imo would be proper price again.

But we can't do a lot for that, do we?

With carbs you could get bit more power out, but I think that you would need some head work and possibly bit of shaping for valves at least to get most of it as that starts restrict again around 150, but from this I have heard only rumours so can't make it a lot credit.

One Finnish guy I know made redblock with wild cam and solex carb (same model carb I have, cisac Z11), was used only for racing but he managed to take out something around 180-190hp from it, valves were stock but intake port was modified a bit and engine had higher compression too, he did rev it to 9000 rpm and he had old spark system from B19, not electronic ignition!
Now he did make new B230 that got more work to head new valves etc with twin carbs he is looking to go 240hp or more. They drive only 3 laps max in that rallycross type racing.

Naturally he is bit shy from details, guy is only 17 and already doing lot of things with cars

So it is possible to take power out quite a lot with odd parts, usability is just quite bad, idle over 2000rpm etc. That intake port is perhaps one to concentrate if you are doing head work, there you can get some gain at those power levels it seems.

[volvorsport]

one word bike carbs , or twin SUs , well maybe thats three of our.

i dont see how a 65mm throttle body is a restriction on something with 45mm valves .

[foggyjames]

On the face of it, you wouldn't think so. Perhaps the inlet pipework is to blame, but my car made nearly 20bhp more (IIRC) than Andy's (MSnS), and his is otherwise identical - and his is higher compression to boot. He was beginning to measure vacuum at high RPM / full load. Whether TB or inlet pipework (etc), something is making a difference.

cheers

James

[jtbo]

one word bike carbs , or twin SUs , well maybe thats three of our.

i dont see how a 65mm throttle body is a restriction on something with 45mm valves .

Are you sure from 65mm?

[volvorsport]

your fuelling might not be as good , but you have a better manifold design .

so you hit the nail on the head .

however the VOC boys hit 170 with 2.3 , so what are you doing wrong ?

[volvorsport]

one word bike carbs , or twin SUs , well maybe thats three of our.

i dont see how a 65mm throttle body is a restriction on something with 45mm valves .

Are you sure from 65mm?

it might be 55mm , i was measuring allsorts about 3 weeks ago , so it might have been a whiteblock one i was thinking about , still ,the TB isnt the real restriction .

one thing to notice is that on turbo compared to NA whiteblock examples the turbo always has a smaller TB .

[jtbo]

one word bike carbs , or twin SUs , well maybe thats three of our.

i dont see how a 65mm throttle body is a restriction on something with 45mm valves .

Are you sure from 65mm?

it might be 55mm , i was measuring allsorts about 3 weeks ago , so it might have been a whiteblock one i was thinking about , still ,the TB isnt the real restriction .

one thing to notice is that on turbo compared to NA whiteblock examples the turbo always has a smaller TB .

55mm would be 174hp, 52mm would be 155hp so very small change will mean a lot, can't remember how much it was when I did measure it as it was so long time, but it was very close to what injectors are capable of @ 3 bar fuel pressure, remember our cars there has only 2.5bar fuel pressure, it was 143hp with 3 bar pressure as I did check now and 130.5hp with 2.5bar pressure that injectors are capable of in NA engine, so those surely are going to end first.

Edit: with turbo you can get away with smaller TB, that is not restricting as much as with NA so you can't compare those directly, this is what I have been told.

[pettaw]

Its neither, IIRC, its approx 59mm, and yeah its not the restriction, its the manifold itself with silly small sized tubes.

[jtbo]

Its neither, IIRC, its approx 59mm, and yeah its not the restriction, its the manifold itself with silly small sized tubes.

Tubes are 38-40mm each, but design of manifold is not very good at all, tubes are too short and I'm pretty sure that air volume is just all wrong, also there is places for injectors that makes nasty narrow section to tubes.

Haven't calculated yet best manifold, but tubes should be at least 45cm range (17.7 inches) after quick lookup.

With good manifold injection engine can get quite big boost in performance, with carbs it would be bit harder to make so good use of frequencies.

For 2ltr engine and for 3500rpm it looks like tubes should be 35.9mm (1.413382inches) in diameter and 457.5mm (18.01176 inches) long.

Manifold air space plenum diameters would be diameter 68mm (2.677157 inches) length 438mm (17.24404 inches) if we use standard 59mm throttle plate and if 59mm is precise. Of course you should not that bends in intake tubing and tube shape affect this a bit and all, but for this you could get quite nice 10-15% more torque for track use, maybe more depending how bad stock manifold really is, but 3500rpm is bit high for road use.

[A M R]

dai care to 'bodge' something together?