Time for some more power.
- Thread starter GT1261
- Start date
Fast Freddy
GPS'D 225 MPH
i have heard of a GT making 835 rwhp with a 4.0L and headers, etc on the stock motor....
Black GT
GT Owner
- Jan 2, 2006
- 771
BlackICE
GT Owner
Fubar
Totally ****** Up
Yes, you will need more fuel and yes, post some pictures of the alfa. I got to 780 on 93 oct and 830 on a 105 race fuel. It wasn't my first choice on race fuels, I bet you can do better with vp import. The amount of fuel you can deliver is the limiting factor.
Ok Mark.
I will always listen to your advice. Will ask my installer for the injectors and hopefully we will cjange them out as well.
He says that the best thing to do would be to change to bigger and much stronger pumps but I think that will be a huuuge task for us.
, I'l upload a picture of Bella when I get back home.
I will always listen to your advice. Will ask my installer for the injectors and hopefully we will cjange them out as well.
He says that the best thing to do would be to change to bigger and much stronger pumps but I think that will be a huuuge task for us.
, I'l upload a picture of Bella when I get back home.
FBA
GT Owner
I got to 783 on a 4.0 with a 19 PSI pulley and a BAP/ Exhaust, but on factory intake...and stock injectors, but TQ was below 700...
Not trying to go off topic but this is my other baby. :biggrin
I bought her on my 24th birthday ( the GT on my 27th ) and I have always loved this Alfa model next to the GT40, E-Type Low-Drag and the BMW 3.0 CSL.
Uploading this pictures because our pioneer Mark M asked for it.
The first two pictures shows how she looked before and the last how she is looking these days ( picture 3 ).
I have had her restored for three years now and it is not my GTA on the last picture because I don't have some with the wide body fenders on, but they are identical.
My goal is to make her as close as possible like the old racers back in the days... The funny part is that NO race car was like the other one, they where all different.
If you guys would love to have one, then I can assure you that these cars are really wonderful, full of soul and they are so damn beautiful.
Check this site out, these guys have made some nice builds and they have probably the best parts for the 105 Alfas
http://www.alfaholics.com/our-cars/completed-builds/alfaholics-gta-r-1006/completed-photoshoot/
Enjoy,
I bought her on my 24th birthday ( the GT on my 27th ) and I have always loved this Alfa model next to the GT40, E-Type Low-Drag and the BMW 3.0 CSL.
Uploading this pictures because our pioneer Mark M asked for it.
The first two pictures shows how she looked before and the last how she is looking these days ( picture 3 ).
I have had her restored for three years now and it is not my GTA on the last picture because I don't have some with the wide body fenders on, but they are identical.
My goal is to make her as close as possible like the old racers back in the days... The funny part is that NO race car was like the other one, they where all different.
If you guys would love to have one, then I can assure you that these cars are really wonderful, full of soul and they are so damn beautiful.
Check this site out, these guys have made some nice builds and they have probably the best parts for the 105 Alfas
http://www.alfaholics.com/our-cars/completed-builds/alfaholics-gta-r-1006/completed-photoshoot/
Enjoy,
Last edited:
Fast Freddy
GPS'D 225 MPH
what kind of exhaust setup were you running? did you make this power with headers and no cats? also how much boost did you run? i assume this was done with a 4.0L....
Sinovac
GT Owner
At what PSI will the stock cats start to fail? The oem cats in the GT500 won't survive 19+psi. The high flow cats I got from ARH failed at about 19 psi too, even with a conservative tune.
Good to know !!! I will say to the cops when they stop me:
Dear Officer, I have to much boost to have cats...
Fubar
Totally ****** Up
I had a custom header setup on my car so I am sure there were some different flow characteristics. The headers seemed to give me about 20hp, in exchange for 12-15lbs of torque (those results were highly contested by Bony). I would think the GT cats could handle quite a bit of boost, they weigh a ton but they appear to have massive flow potential. It would be easy to make a cat pipe with higher flow cats (if that exists) but it wouldn’t be something I would worry about.
I think we got to about 780hp with the stock fuel setup (and 93 oct) but it was at the absolute limit of the fuel system. The ECU showed the pumps were at 108%, fuel line pressure was dropping to sub 30lbs and the ECU was compensating by adding fuel injector duty cycle (a bandaid fix) that had the injectors running at 90%. There was just too much potential for problems IMHO. Improving the fuel pump ability is the best solution but I wouldn’t monkey around with trying to improve the current pumps. They are pretty good and your options for a direct fit in the stock position is very limited. In retrospect, I think a third inline-pump probably would be the easiest, most reliable solution but upgrading the injectors gives you a lot of room to play also.
After we did the mechanical pump and the 1000cc injectors we saw duty cycles at 35-50% under max load. The ECU didn’t like that we had removed it’ s pump feedback loop but we got that sorted out and fuel was no longer limiting factor. After that I felt comfortable pushing the 4.0L to 780hp on 93oct. Every person approaches these things differently. This is just the route I choose.
I think we got to about 780hp with the stock fuel setup (and 93 oct) but it was at the absolute limit of the fuel system. The ECU showed the pumps were at 108%, fuel line pressure was dropping to sub 30lbs and the ECU was compensating by adding fuel injector duty cycle (a bandaid fix) that had the injectors running at 90%. There was just too much potential for problems IMHO. Improving the fuel pump ability is the best solution but I wouldn’t monkey around with trying to improve the current pumps. They are pretty good and your options for a direct fit in the stock position is very limited. In retrospect, I think a third inline-pump probably would be the easiest, most reliable solution but upgrading the injectors gives you a lot of room to play also.
After we did the mechanical pump and the 1000cc injectors we saw duty cycles at 35-50% under max load. The ECU didn’t like that we had removed it’ s pump feedback loop but we got that sorted out and fuel was no longer limiting factor. After that I felt comfortable pushing the 4.0L to 780hp on 93oct. Every person approaches these things differently. This is just the route I choose.
Fubar
Totally ****** Up
BlackICE
GT Owner
IMO running cats with the goal of max boost and HP is not optimal. The factory tune has COT (cat over temperature) protection. IE when the ECU estimates the cats are overheating the tune richens the a/f to about 10:1 or even richer to cool the cats down. Without that cooling the cat will have a short lifespan.
Thanks Mark, yes they are fantastic to drive ! Tons of soul !!!
About your fuel problem issues/experience... I will show all your posts to my installer.
If my GT will run short on fuel then I'l probably just ad a third pump, and if that doesn't work
then I think I have no choice than a fuel spraying Kärcher mounted on the roof: :wink
About your fuel problem issues/experience... I will show all your posts to my installer.
If my GT will run short on fuel then I'l probably just ad a third pump, and if that doesn't work
then I think I have no choice than a fuel spraying Kärcher mounted on the roof: :wink