Away back, everyone ran a very low C/R because Porsche was running something like 7. But that was with air-cooled heads. Low detonation point.
The compression ratio should be fine if you aren't going for big power. My 2L Nord is boosted with the same compression ratio. Currently running 6 PSI and has been running without problem. With modern engine management, you can get away higher compression ratios than they could back in the days of carbs and air cooled engines (i.e. the old turbo Porches). If you are looking for 20psi and 300hp, then lower compression is in order (among other things).
I'm running a Garett T28, but there are dozens of turbos appropriately sized for that application and power output as 200hp 2L turbo motors are extremely common in OEM applications. I'm running a custom manifold and downpipe. Frankly, it's the requirement for a custom manifold and downpipe that is the biggest issue in turbocharging a spider- there are very few off the shelf options.
Here is a thread that may intrest you its not about turbo charging but increasing power
It runs and drives great. Feels like a stock motor until about 2500 rpm and really takes off over 3500 rpm. As for reliability- it's too early to tell. I've ragged on it pretty hard- but I don't drive the car on a daily basis, so I can't tell you whether it will last 20k miles. You are probably pretty safe for a long time at 6psi (~170hp). 8psi is probably safe too (~200hp), but you are rolling the dice above that. There aren't enough boosted Nord engines out there with modern turbo setups to really get a sense of its limits in real world conditions.
I am doing it for a gt junior , but i guess since these are nord engines should be all simular , so ill have to go for a down pipe?
I don't know much about the jafco kit, but I understand it's pretty ancient as far as turbos go. You may need to modify the flange to get it to accept a modern turbo.
I'm obviously a bit biased, but I've always thought that trying to wring more power out of a small little four banger (especially an old school 8v one) without boost is a lot of work for not that much gain. Unless you are running in a vintage race series that bans boost, I would go turbo every time. Anything more than a mild bump NA means a complete engine rebuild. If you are going through all that trouble, why not build it for boost and get double the power? >
My understanding is that you are basically SOL in CA. I'm in Texas and have the car registered as an antique- so I have no inspection or emissions requirements at all.
Honestly, I wouldn't bother. The actual turbine is a small part of the cost of a good turbo setup. Far better to get something new and standard.
Ill deff look into the turbo you got , i guess jafco s are old turbo s , by what you described the turbo kicking in at 2500 rpm would be perfect for what i am looking for
If you are less ambitious in output goals, you might want to go a little smaller than what I have and get an even lower boost threshold and less lag. I wanted to leave the option open to build the motor and go for 300hp. The Garett T28 is not the absolute best turbo for the application, but it does happen to be extremely common and cheap.
As long as Mikethree's Alfa is pre-1976, he isn't subject to emissions inspection, so a turbo would be OK here.
