Punto GT 1.6 project

Road-race engines and ancillaries - general discussion
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Kranked
Posts: 12
Joined: May 13th, 2010, 2:46 pm

Punto GT 1.6 project

Post by Kranked » May 15th, 2010, 9:15 am

Hi all!

Firstly I would like to thank GC to be here.

My project has started a 2 years before. I had an 1.6 Sporting Punto MK1 and I would like to get more power so I decided to bulild an 1.6 turbod engine. I bought an 1.4 GT2 and used this as donor car. We replace the braking system, clutch, gearbox, wiring and ECU, dashboard, all sensors, etc.
The GT2 run with 7.8:1 CR so we needed to reduce the Sporing engine 10.5:1 CR to this value. We used a proper metal head gasget to do this. I bought a Piper Rally 280/258 camshaft but we dont timed - we used the standard settings. The turbocharger was an K03/K04 with 1.4bar (about 20PSI) pressure+240cc/min injectors. The engine run about 20.000 miles with this configuration without error.

The power was not enough for me so I bought Megasquirt2 V3 and the car programmed to Bioethanol [E85, Superethanol, etc] fuel and to 1.7bar [24.5PSI] pressure + 350cc/min injectors.

The bioethanol fuel has 105 octane so I think to increase the CR to 9:1 or more [ the standard GT3 run with 9:1 CR], and with this CR I can run lower boost with more power.
My second idea to do head cylinder modification: porting, polishing, and maybe bigger valves, stronger camshaft springs, and timing correctly the cam.

What are you thinking about the CR? Can you help me what I do with the head cylinder to get more power?

Thanks a lot: Kornel

Guy Croft
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Re: Punto GT 1.6 project

Post by Guy Croft » May 15th, 2010, 6:15 pm

I want some good quality photos of the head showing combustion chamber, ports,

G

Kranked
Posts: 12
Joined: May 13th, 2010, 2:46 pm

Re: Punto GT 1.6 project

Post by Kranked » May 21st, 2010, 10:21 pm

Hello,

a can show you some photos maybe the quality will be enough:

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Thank you for your help!

Kornel

Hexer
Posts: 11
Joined: May 5th, 2010, 2:04 pm

Re: Punto GT 1.6 project

Post by Hexer » May 24th, 2010, 7:02 pm

I think the compression ratio will be ok, but don't go over 9:1 because 105 octane isn't really that much, but bee aware that as the ratio goes up the cylinder peak pressure rises as well so you will face some mechanical problems, I'm thinking on the rods and main bearing caps, most of the turbocharged cars bend and eventually brake the rods and the bearing caps begin to move around because of the stress of to high cylinder pressure.

Attention with cam selection because the E85 burns slower then gasoline, so if you open the exhaust valve to early you will catch the flame front an thats way to hot for the valves, even Inconel or nimonic no mention on the original ones with gray cast liners (think I saw write on the photo attached).

Kranked
Posts: 12
Joined: May 13th, 2010, 2:46 pm

Re: Punto GT 1.6 project

Post by Kranked » May 25th, 2010, 10:36 am

Thanks your reply!
I googled a lot and found some infos about CR vs boost. After that infos I think lower CR with higher boost better than higher CR - lower boost. I think the power difference between 7.8:1 and 8.5:1 is low but the lower CR is much safer. What do you think about it?
Here is some details of the cam:

Powerband : 2600-7500rpm ; Power increase : Not Specified
Inlet duration : 280 deg ; Exhaust duration : 258 deg
Inlet valve lift : .452"/11.50mm ; Exhaust valve lift : .393"/9.98mm
(Valve lifts quoted assume a rocker ratio of 1:1. )
Timing (Inlet open - close) / (Exhaust open - close) : 30-70/59-19
Inlet full lift (ATDC) : 110 deg ; Exhaust full lift (BTDC) : 110 deg
Valve clearances : Inlet = .016"/.40mm ; Exhaust = .018"/.45mm

I bought the cam before I used the car with bioethanol, so I hope it was not wrong choice...With adjustable timing gear can I get better performance?

Hexer
Posts: 11
Joined: May 5th, 2010, 2:04 pm

Re: Punto GT 1.6 project

Post by Hexer » May 25th, 2010, 7:29 pm

8.5:1 is more than ok if you don"t want over 200hp/liter with bioethanol, even 9:1 is ok, but this is jut the knock limit part of the story, the mechanics will be the weak point.

Regarding the cam, it's a good street cam, yet I don't know how the opening and closing was measures, with or without clearince, 0.1-0.25 mm opening, I think the most useful measuring form is what catcams.com use giving their cam profile, you should measure your cams.
With your turbo at TDC the exhaust its ok at 1-1.5mm + clearance, this should mean that the intake opens around 2.3-2.6 + clearance.
The timing gear is definitely a good idea, not for performance but to place the cam at the right location, where is should be in the first place.

Kranked
Posts: 12
Joined: May 13th, 2010, 2:46 pm

Re: Punto GT 1.6 project

Post by Kranked » July 28th, 2010, 11:17 am

Hi!

My new cylinder head is ready to install. We calculate the new CR and it is about 9.0-9.2:1.
I know this is very high for turbod engine but - as I wrote before- I will use the car only with E85 bioethanol. The stock Punto GT3 has 9.0:1 CR and the factory build it to use with RON 95 gasoline (and with 0.8-1bar pressure and remapped ECU).
Can anyone tell me what is the max pressure what can I use wit this CR and E85? My friend has a "stock" GT3 (bigger intercooler , T3 turbo, timed 280 camshaft, 330ccm injectors, remapped ECU) and he use the car with 1.4-1.5bar pressure and can run 13.8 on 1/4 miles.

Thanks!

Kranked
Posts: 12
Joined: May 13th, 2010, 2:46 pm

Re: Punto GT 1.6 project

Post by Kranked » March 20th, 2011, 11:07 am

hi everyone!

new year - new session - new plants!

The car works perfectly but not the higher rev range. Over 5000 rpm the car's performance very poor.
I think it has two reason:

the first is the small turbo: K03/K04 has a small turbine wheel
and the second: high camshaft overlap degree (asp valve apertures: 30°‑70°,
exhaust valve apertures: 59°‑19° --> 49° degree overlap!! )

What do you think, this reasons can result high back pressure and give poor performance over 5000?

I will replace the turbo with a Garrett T3 turbo (Garrett TBO356, turbinewheel: 59.00 / 47.95 Trim65, compressorwheel: 60,00 / 42,50 Trim50) and it will decrease the back pressure and allow the car revving to higher rpm range.

My question is the cam: I read about turbo cams and a lot of people say the overlap is should be minimal in turbo cars.
I have a stock 1.6 sporting camshaft which has lower, 13 degree overlap (asp valve apertures: 6 °-46°,exhaust valve apertures: 47°-7°) This cam will work better than the Piper cam? I would like max 7500 rev limit not more...

Thanks: Cornel

p.s.: the stock Punto GT cam has the following specs: asp valve apertures: 0°-43°, exhaust valve apertures: 40°-3°

WhizzMan
Posts: 459
Joined: August 13th, 2010, 9:05 pm
Location: Amsterdam, the Netherlands

Re: Punto GT 1.6 project

Post by WhizzMan » March 23rd, 2011, 7:36 am

I'd try the stock cam first, or use something that opens the inlet a bit more. On twin cams, it usually doesn't pay to change the exhaust cam from a stock turbo until you go for more than twice the power the turbo engine gave stock.

Did you polish the ports and do a good valve job on your head? Even with a turbo, there is quite a lot of gain to be found there. The valves in your pictures looked like they don't close very well, so I hope you fixed that.
Book #348

Kranked
Posts: 12
Joined: May 13th, 2010, 2:46 pm

Re: Punto GT 1.6 project

Post by Kranked » March 26th, 2011, 4:42 pm

Hi WhizzMan!

These pictures of the head is not mine, my friend shoot some pictures about him cylinder head. In my head I use bigger exhaust valve, and yes, I polished the ports and did a correct valve job. First of all I will try the stock cam I will write my opinion about it!

Thank you for your reply!

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