Dr.Jeff
True Classic
As you know....Thanks for all your replies. The Dallara style head from CF Motori looks really interesting but may be too costly. The more I think about it, going for the SOHC is the most interesting way to keep it close to the original. -With or without a 16 valve head. -With or without turbo. I have lots of power in my street X so I probably wouldn't be happy with less power in a race Dallara. The cheapest way to obtain power is going turbo so another crazy idea popped up:
I have a 1500 in spare so why not stroke it to 1600 and turbo it? Not a mild turbo setup like @Dr.Jeff is working on, I want 300hp from it. It has been discussed that the 138 "siamese" block is weak, and cannot handle the heat, lubrication etc. but if Graversen managed to get 370hp from a stroked 1300 I think it is doable. The design of the 1500 is very like the Uno Turbo in many ways so it is probably much tougher than most people think. But crank, conrods, and pistons must be upgraded of course. I will have lots of time to plan and think about the engine until time comes.
Got some tips and ideas on FB (thanks Julian Brown if you are a member here) for framing and tubing. The pics show a very robust cage, probably much safer than an original Dallara, and some parts of it are probably necessary to meet modern regulations. But the build (from UK) has no front suspension framing due to national regulations. However, this is allowed in Sweden even on a street legal car so a Dallara front suspension pic would be interesting to study.
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I believe one difference between the SOHC 1500 block and the UT block is the spacing of the cylinders (better spaced apart on the UT). Obviously another is the bore diameters, and that gets even worse on the 1500 block when you bore for a 1600 displacement (thinner walls). Therefore the UT block is stronger and more resistant to high thermal failures.
However I think the 1500 block can work if you build a really good cooling system; e.g. electric water pump, large radiator with huge fans, managed by a module to allow closer thermal control and after-run cooling, ported cooling passages, etc. And a good oiling system; e.g. large oil cooler, high volume pump (which doesn't exist but we've discussed a potential way to help by modifying the bypass valve), ported oil galleys, etc. As you say it will need upgraded turbo spec internals; SS valves, custom pistons, forged rods and crank, MLS gasket, aftermarket studs throughout, etc. At that point you should be able to feed higher boost levels without mechanical failure. Although it will still need considerable flow improvement in the head to reduce flow resistance (which leads to exponential thermal increases); major porting, turbo spec cam, etc. A huge intercooler with help with internal thermal management, but a very well tuned ECU and supporting components (fuel and ignition) is also mandatory.
It is certainly doable with the right budget. That was my limitation and why I chose to go with a conservative low boost setup. But I admit the thought to go big is very tempting.
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