GTT Stage 4 Head ..50bhp increase?

[roland2003]

Weve just had a look at some of the power gain or outright power of a couple of cars with GTT heads, and thought we would put them up to see.

-Our (standard SC) 'GTT260' demo car on GTT Stage 2 head (uses stock size valves) ..273bhp (240WHP).
-Tony Fenners car with GTT Stage 3 head ,stock intercooler, 17% pulley .....from memory the head gained 35+ bhp. compared to pre head power runs.
And Finally Alans GP . This went from 211bhp to 252bhp (still std intercooler) with the addition of just GTT Stage 4 head, Shrick cam, and going from 15% pulley to 18%. (also the required GTT fuelling mods ) ...Thats 41 bhp increase. Although a colder day the Din70020 correction should adjust accordingly therfefore the ambient temp should make no difference to the figures achieved.
Theres one other thing overlooked .....those increases are 'on top' of a GP head! which already has larger exhaust ports. If the car had been on a standard MCS head , that increase may well be over 50bhp.
Lees 'GTT300T' with the addition of GTT Stage 4 head and Shrick Cam achieved 391bhp.
Remember this is a customers car, headwork more than any other product can vary . Even with CNC machining theres huge amounts of hand fettling. Heres the proof that our production heads are every bit as good as our 'demo/own car heads.
-CNC Milling is our Forte......thats my original trade.I might do a technical thread on the CNC milling we use on our heads,...theres CNC milling (no big deal tbh) and theres GTT 3D milling (ports ,throats, & valve seats )
-

[Aberdeen Al]

[Hyper Active]

This might be a silly question , but if a GTT Stage 4 head is put on a standard 170bhp MCS, would it then be running at 220bhp ?.

[Aberdeen Al]

Quote: Originally Posted by Hyper Active (original)

This might be a silly question , but if a GTT Stage 4 head is put on a standard 170bhp MCS, would it then be running at 220bhp ?.

Good question.........

[roland2003]

I could produce a GTT Stage 4 head that would produce 50bhp gain on a stock MCS .
Actually that 'Special Stock Pulley Head' would not be suitable for a pullied car but would look mighty impressive for publicity.
Hows it done? .....Simple you just increase the CR at the same time,run some high octane fuel and as long as your still running stock pulleys 50bhp increase from just a GTT head on a 163/170 bhp standard car is definatly possible. That head would be hopeless with a small pulley though so you wouldnt sell it to someone as they would probably want to change pulleys and use pump fuel causing it to detonate/blow up .
A 'genuine' production Stage 4 head (capable of small pulley use etc) I would guess around 200bhp, but this is not the best /most cost effective power route to go.

[roland2003]

One other thing regarding our Stage 4 heads. We are fortunate enough to have just bought a large quantity of BRAND NEW MCS heads. Therefore our Stage 4 heads will no longer be on exchange . You get to keep your old head ,plus you can be safe in the knowledge your 'new' gasflowed head has not been torn off someone elses car and just cleaned up to look new.

[alski]

stage 3 and 4 whats the difference, valves?

[roland2003]

Yes Stage 3 uses Ultrik valves. Stage 4 Uses Shrick .
Ultrik are cheaper and smaller and what many 'big valve' heads use. The Shrick Exhaust valve we use is 2.8mm larger in diameter than stock.(that is BIG) .
But the GTT CNC milled seat and throat ,...thats even bigger!
5mm bigger in diameter than stock to be exact .
If you calculate the increase in cross sectional area of the Exhaust valve seat internal diameter or the throat..... thats an increase over stock of 63%.

[Jaw_F430]

Quote: Originally Posted by roland2003 (original)

One other thing regarding our Stage 4 heads. We are fortunate enough to have just bought a large quantity of BRAND NEW MCS heads. Therefore our Stage 4 heads will no longer be on exchange . You get to keep your old head ,plus you can be safe in the knowledge your 'new' gasflowed head has not been torn off someone elses car and just cleaned up to look new.

How much is a stage 4 head then? And what would be the additional cost to add a camshaft at the same time as swapping the head?

How much difference does it make from 15% pulley instead of 18%? As I run a 15% pulley


Regards


James

[roland2003]

Outright purchase on brand new GTT stage 4 is £1295+vat. (excluding fitting)
When fitting any GTT head if were supplying the cam aswell then theres no extra fitting charge for this. We would advise GTT 440cc injectors & GTT Adjustable FPR at the same time. (Thats what Alans car has).
We can run it with either the 15% on its own or add the GTT +3% 2 piece alloy crank pulley,this gives equiv of 18% plus reduced rotational mass as it weighs only 1 pound aginst 5.5 or 7 pounds for the stock item. You can even purchase the GTT crank pulley wheels seperate from the sleeve part ,allowing changeover of diameter crank pulleys in about 15minutes . (if the inner arch is left out. temporalily) .Therefore we can try 15/16/17/18% if necessary.

[Jaw_F430]

Quote: Originally Posted by roland2003 (original)

Outright purchase on brand new GTT stage 4 is £1295+vat. (excluding fitting)
When fitting any GTT head if were supplying the cam aswell then theres no extra fitting charge for this. We would advise GTT 440cc injectors & GTT Adjustable FPR at the same time. (Thats what Alans car has).
We can run it with either the 15% on its own or add the GTT +3% 2 piece alloy crank pulley,this gives equiv of 18% plus reduced rotational mass as it weighs only 1 pound aginst 5.5 or 7 pounds for the stock item. You can even purchase the GTT crank pulley wheels seperate from the sleeve part ,allowing changeover of diameter crank pulleys in about 15minutes . (if the inner arch is left out. temporalily) .Therefore we can try 15/16/17/18% if necessary.

How much are the 440cc injectors and GTT Adjustable FPR, I have 380cc injectors at the moment would the cost be on exchange basis or would I keep the 380cc?

I am just trying to work out my next mods which at the best value for money and might as well go for a stage 4 head instead of getting a stage 2 which I was going to go for


Regards


James

[Ant FR]

Quote: Originally Posted by roland2003 (original)

Outright purchase on brand new GTT stage 4 is £1295+vat. (excluding fitting)
When fitting any GTT head if were supplying the cam aswell then theres no extra fitting charge for this. We would advise GTT 440cc injectors & GTT Adjustable FPR at the same time. (Thats what Alans car has).
We can run it with either the 15% on its own or add the GTT +3% 2 piece alloy crank pulley,this gives equiv of 18% plus reduced rotational mass as it weighs only 1 pound aginst 5.5 or 7 pounds for the stock item. You can even purchase the GTT crank pulley wheels seperate from the sleeve part ,allowing changeover of diameter crank pulleys in about 15minutes . (if the inner arch is left out. temporalily) .Therefore we can try 15/16/17/18% if necessary.

Ok, Roland does this answer the PM I sent you yesterday, does that mean wilcox head plus GTT cam, would be 1085 + VAT fitted ????

[MINI-Morgan]

If only I had the cash.....

[roland2003]

1320 .. As requested by the moderators could you please give us 'space' (ie less interference)to promote our products and achievments on our threads...cheers.

Just to confirm:-
The GTT273bhp (240whp) was 'only' using our stage 2 head which uses standard valves. We did change to a GTT Stage 4 a couple of weeks before removing the car from the road for the GTT 300T project (which was just over a year ago) I.would say the power gain was quite noticable on top of the above figures but not dynoed at this point . There are graphs on the other thread to prove the 273bhp.

The '35bhp gain' on GTT Stage 3 head was Tony Fenners (Fone). I dont think the graphs were ever put up but hes certainly not in the habit (or have reason )to lie. Maybe he will if he sees this thread.

The 41bhp gain (over a GP head ) was Alan Whites (Snowie) . This was at the Surrey RR day. ...252bhp ,whereas previous to the GTT Stage4 head/cam ,extra 3% on the pulleys and a tweak from us on the GTT Adjustable FPR , it achieved just was 211bhp n the same RR. This was the highest power MCS there on the day ,beating a tuners own car aswell. We were very pleased with these results, expecially as there are still areas of this car still to be modified if the wife lets him.

ps Ant..... I'll work out a price for you tommorow.

[roland2003]

Ok, I wasnt dead sure on that one. Good result Graham. As I said Alans still hasnt got a full house of mods yet like yours, he runs stock rev limit & map.
Regarding the various different stages of heads we offer, there are fundamental differences between them both in the areas that are CNC machined ...eg just the ports, or ports + throats, or ports+ throats+seats. Also the valves we use . ie stock or Ultrick or Shrick.
Always ask what make & size are used. The Shricks are about 3 times the price of Ultrik hence the use of them in our top head. Also ask what diameter the inside of the seats & throats are opened upto.?.... This is even more important than the valve size itself . Also find out how much and how far the fettling and knife edging of the port divider extends to. This is alot of work that you cannot do so well on the CNC ...its tempting to leave this out or reduce the effort in this area but not us even on GTT Stage 1 head.