CityTurbo.com

hey guys
i want to make the ultimate city engine, so if you guys wouldnt mind could you share some quick ideas about performance

modifications??
how did they improve??
any problems that arose??
how happy you were with them??

guys if you could share a couple of ideas
that would be the best !!!!

thanks again guys
mitch

I suggest the following as a minimum :

1. Get rid of the CVCC head and fit an NA 8 valve head
2. Modify 8 valve head to take Turbo inlet manifold and fit bigger valves and injectors
3. Fit +1mm forged pistons
4. Knife edge the crank
5. Shootpeened or forged rods
6. 4 speed GB gearbox (4.91 diff ratio)
7. Fit a quaife LSD
8. Fit an aftermarket computer
9. Big exhaust, dump valve & pipe etc
10. Ball bearing turbo
11. Front mounted intercooler

Or do what one of the Kiwis did (Turbo3 ?) and fit a custom inlet manifold, very nice !

You got to get rid of the CVCC head and fit a good aftermarket computer.

ok i got most of that

please explain why only a four speed gearbox??

all these thing will improve which part??

like top speed, torque etc ect??

thank you very much for your help

The T2 diff has a final ratio of 4.06. The GB 4 speed has a diff ratio of 4.93. This is much better for acceleration.

By fitting an aftermarket computer you get rid of the boost and rev limiter, and can map the fuel and ignition to anything you like.

Mark_Moddy wrote:I suggest the following as a minimum :
1. Get rid of the CVCC head and fit an NA 8 valve head
2. Modify 8 valve head to take Turbo inlet manifold and fit bigger valves and injectors
3. Fit +1mm forged pistons
4. Knife edge the crank
5. Shootpeened or forged rods
6. 4 speed GB gearbox (4.91 diff ratio)
7. Fit a quaife LSD
8. Fit an aftermarket computer
9. Big exhaust, dump valve & pipe etc
10. Ball bearing turbo
11. Front mounted intercooler

IMHO I think if you are going to go to all the work of customising a non-cvcc head then you are wasting your time sticking with the 1231cc, just upgrade to a 1600 or 1800 block. Even by the time you've spent 2+grand on forged pistons and rods I would probably go for a 1600EL and get the forget bits for that. Would cost the same and would make SOOO MUCH more power.

I also dont think getting rid of CVCC just because its not understanded thoroughly is a good idea.

this is my list in order of how I would do them:

1: Exhaust, 2.5", maybe 3" dump
2: Front mount cooler, square or rectangle core, not a long skiny one
3: light p&p of T2 head, paying special attention to short side radius and around the bowls. 5 angle seat job.
4: Custom intake manifold with ~60mm throttle body. keep cvcc throttle system tacked on the side.
5: Aftermarket ECU. Batch fire all 5 injectors. Possibly consider changing to wasted spark ignition system (bin the dizzy).
6: Upgrade fuel system. Lift pump into surge tank with a 300hp inline pump from there.
7: Larger injectors, 240cc should be enough.
8: Larger turbo on tubular equal length manifold. Not too big, possibly one of the larger variants of the garrent T25, go for a GT25 ball bearing if you have money to burn and want the 9% faster spool.
9: Forged pistons, I would only go enough OS to get good clean bore, maybe 0.25mm.
10: Billet conrods.
11: Crank scraper.
12: LSD and rebuilt gearbox

have either of you two done any of these mods??

which one was the best and made the biggest improvment??

thanks again

1: Exhaust, 2.5", maybe 3" dump

Done, huge difference, well worth it.

2: Front mount cooler, square or rectangle core, not a long skiny one

Done, also huge difference, and only cost me about $20

3: light p&p of T2 head, paying special attention to short side radius and around the bowls. 5 angle seat job.

I have a lightly port and polished T2 head with a 3 angle valve job and new springs and stuff in my car, not sure how much difference it made 'cause I didn't drive it without.

4: Custom intake manifold with ~60mm throttle body. keep cvcc throttle system tacked on the side.

I have one of these in my garage that colin made, he never got it running properly becuase of a busted ignition coil (found out after taking it off). I should probably give it another go at some stage.

5: Aftermarket ECU. Batch fire all 5 injectors. Possibly consider changing to wasted spark ignition system (bin the dizzy).

Its in the works

6: Upgrade fuel system. Lift pump into surge tank with a 300hp inline pump from there.

I have made my surge tank and have an in-tank fuel pump from a h22a prelude to put in it, just have to mount it.

7: Larger injectors, 240cc should be enough.

Lots of people have done this, runs stupidly rich without some way to tune them.

8: Larger turbo on tubular equal length manifold. Not too big, possibly one of the larger variants of the garrent T25, go for a GT25 ball bearing if you have money to burn and want the 9% faster spool.

Done by a few on this forum, some quite succesfully.

9: Forged pistons, I would only go enough OS to get good clean bore, maybe 0.25mm.

Angus Button's city had forged pistons and rod's, only one I know of.

11: Crank scraper.

No personal experience but I have been researching recently, they seem like a damn good way to make a few extra % HP

12: LSD and rebuilt gearbox

Working on both