Best way of induction with one carb?

[Westfields Rock On]

how do chaps. as some of you know im wanting to make my triumph GT6 go fast. I have decided to bang a blower on the b@st*rd with a single blow through carb. my ideas are illustrated below. the 1st 2 are chopping a manifold in half and putting on an airbox, and below are using the current manifold, bolting an airbox to where the current twin SUs are. I have no idea which is the best location for the carb of the two either. Any Ideas would be a great help. Thanks

[hilux]

HI Wrox

FWIW I`m not a Triumph expert but understand British Classic Cars................

GT6 engine is an old fashioned long stroke that revs adequately and then explodes at high revs if not carefully balanced and strengthened. A blower gives loads of low torque so is probably a preferred method.

I feel that you could go the 2.5PI route or with carbs (150+bhp) fro a TR6 or saloon.

What about fitting an aftermarket `Zetec` on carbs.

Fitting a blower is a fine idea but the carb/needles (I assume SU) will need to be carefully matched to the progression and much increased airflow or you`ll have detonation and stuff the engine. Note also that it takes a lot of power to drive a blower, its not `free` power like a turbo.

I know that with a turbo you need a much lower compression ratio so if thats the case with a blower then with your 6 pot you`ll have extensive work to do re shorter con rods or aftermarket pistons.

The extra power (potentially 30% more) will strain the crank so that `may` need better journals/shells etc Note that those cranks are famous for excessive endfloat so it may need specialist machining or a specialist crank.

What power do you have?

I would have thought that a decent cam and more fuel (better carbs or double carbs) would see a useful gain in HP.

Note that losing as much weight as possible gives noticeable gains and is cheap and upgrading your brakes will enable higher speeds into corners.

[pookie]

S.U. carbs are not good at being blown through. The only one I can think of was used on the Metro turbo,however a vast range of needles are still avaliable.

I would agree with Hilux on the 2.5PI route and removing the original airbox and connecting rubber hoses and using 40DCOE ram pipes gives a noticable power increase for a very modest outlay.

Pookie

[Westfields Rock On]

the 2.5 is heavier, the PI is crap and expensive. also the torque produced would destroy the gearbox. i currently have 125bhp and 135lb/ft torque with full sports zorst, twin HS6s, comp ign, roller rockers, longer endurance cam.

My engine is totally reconditioned. to get a 2.5pi of the same condition the lay out would be around £2k. Also the fuel consumption would be more.

Ive got a new metro turbo carb coming. The bottom ends will take 200bhp standard. To use triple carb setup would cost over 1000pounds anyways for custom manifolds and new webers and a custom linkage( and my mates never work right on his 2.5 anyways), cam £125, heads are rip off, exhaust £350. Its cheaper this way and i keep reliability. The blower takes about 20hp to run. compression will be lowered with a copper gasket, rods and pistons the same. Ill be running it rich as not to melt the pistons but on cruising the MPG will be great due to using 1 carb on a bypass and not a constant 3 munching fuel all the way.

Getting PI to fit under b@stard bonnet is another thing.

you guys got anyideas which would be the best way to mount the carb like above?

[Westfields Rock On]

shallnt be doing these revs any more! that on in front is a 2.5 with everything don to it on triple webers

[stu999]

the 2.5 is heavier, the PI is crap and expensive. also the torque produced would destroy the gearbox

So what kind of hp/torque are you expecting, by blowing (up?) your existing motor?

[hilux]

So what kind of hp/torque are you expecting, by blowing (up?) your existing motor?

*cough*

If the PI/carbed 2.5 is gonna stuff your gearbox through torque issue then a blower is going to annihilate it.

With respect Wrox it sounds like you need to be budgeting for a new gearbox. BTW type 9`s are good for up to 200bhp I believe (awaits being shot down)

What about an XE or Zetec? Sounds a cheaper option to me....

you guys got anyideas which would be the best way to mount the carb like above?

Samco hoses with support brackets is easiest IMHO.

Research fuel/air flow rates on a blower and compare to what air an SU will shift and enrich reliably. If SU`s arent too expensive it should be simple to make a plenum with one pressured air supply feeding two carbs balanced with an adjustable internal damper. Remember that if the progression isnt spot on you`ll melt your pistons in seconds.

If its been done before then a thicker gasket will indeed lower the CR. However the added pressure (considerable) will see this as a weak spot so if its been done before then fine but if not then research it further.

If you go down this route then I highly recommend a knock sensor that will trigger a fuel shut off valve if you get detonation (you`ll coast until the fuel comes on again)

Not discouraging you, simply trying to help. However it goes we`ll be learning alongside you.

Just a thought, what about an MX5 engine. Same power (ish), revabble and an off the shelf supercharger is available for when funds allow?

Good luck

[S8ight]

could be worth a call to derek chin engineering, they do blowers for older stuff.

or what about some reece fish or amal bike carbs ??

mate of mine used to run one of his minis on a pair of fish carbs, it made quite a lot of difference  

[Westfields Rock On]

The engine has to be Triumph. Old school motor it has to be because it pisses off drivers of new cars, and buying a honda S2000 or TVR straight six is going to cost masses. I cant use a 4pot because it would ruin the cars character and name. I would go down the N/a tuning side but theres a barrier at 220bhp with it and its a s**t load of money to get there. My mate has spend over £45k on his GT6 and has 220bhp on top tune, but has to run it at 165bhp due to it being unreliable, stalling, overheating. This way im keeping the block standard appart from lowering compression so should keep reliability.

This is what im going for except on my 6 pot. bhp wise and torque wise im looking for around 150lb/ft - 160bhp. The 2ltr should keep the gearbox in tact better than the 2.5 as it will have just that little less torque. my mates GT6 is running 165bhp and 160lb/ft.  

If my new gearbox goes pop i have to use a supra 5 speeder on a backplate with super/GT6 meshed clutch plate at around £1600.

Using a plenum on standard SUs = fuel and air p******** our of holes in the carbs and spindle holes. I asked andrew turner about this who advised the turbo carb.

Plus this way when I want I can change the pulley and increase/decrease the power when i want. When the quaife diff goes in and better gearbox in 5yrs time it should be around 200bhp.

Dont forget im only 19. My mate keeps saying "I just wanna see Phil come past me at 150 in a ball of flames!"

[hilux]

I cant use a 4pot because it would ruin the cars character and name

I think you are taking the purist aspect too far. If 45K only gets 220 unreliable hp then you need to read `Retro Cars`

Mk II escorts with Xe engines, frogeye sprites with bike engines etc etc. This month there's a Spitfire with a blown RXT engine (450bhp)

I had a concours winning Rover P5B Coupe with a Vitesse engine  

Good luck anyway

[Blatman]

How much money you got to spend Wroxy? *All* your previous posts that talk about adding horsepower (to the Westfield admittedly) have been predicated upon the fact that it has to be cheap. Blowing the GT is not going to be cheap. I know *nothing* about GT6 mechanicals, and not much more about superchargers but from what I can see here it's already looking like a two grand project, and it'll probably be a lot more...

[scruffythefirst]

What about megasquirt at a single point injection system?  Should be a lot safer than a carb, easy enough to find a single point injection throttle body in a scrappy.  Then all you need is a manifold, Scharger and pulleys, mapping and decompression plate.  Easy peasy and to up the power at a later date just put a smaller pulley on the S-charger and re-map.  Cost a lot less than 2k.

[Westfields Rock On]

I get Retro cars I once put in for them to do an article on my car when I read the 1st issue. Miserable gits replied once and then fobbed me off.

project is going to cost around £800.

£230 for the carb

£90-100 for the charger

£30 for a pulley

£130 for a water pump + £80 for controller

£20 for a belt

£5 for airfilter

£5 for a manifold

£20 for pipes

£30 for airbox

£10 for inlet manifold

ally brackets and stuff say £100.

I know its better to use modern technology. But I like old technology. If i could get my hands on a mint shorrock i would use that but theyre nowhere to be found. If I was to use modern technology Id be using a TVR six. They make me horny. But I just cant make myself do it. I love that Triumph six sound. Its downright sexual. The most im going to do is eventually get 3d mappable ignition and maybe after that some trottle bodies. But at the mo the carb route is cheaper. I mean making injection systems is expensive as it is.

[Blatman]

Nothing in that list about a new head gasket or how you're going to lower the compression, and no roller time in the budget to make sure that the first time you run it it isn't going to destroy itself. Then you have to tell your insurers. As with any kit car/modded car upgrade, check the budget, then double it. It's the little things that will add up...

[Westfields Rock On]

am pondering the head gasket. whether to bother or not. that video of that spit engine is running at 11.4:1 comp ratio. rolling road will be about £120 and it costs nothing to add it to insurance.