Just remember that over in the USA the esteemed Jake Raby made his last two Camper Special T4 engines a while back for $25000 each. Now he does Subaru conversions. There is an issue to increasing power over long distances with a T1 engine or a T4 and that is over heating. Flat 4 'aircooled' drag racing engines push massive power but some do not even have fans or fins on the cylinders as they only have to deliver power for maybe 20 or 30 seconds then they are towed back. The stock fan on a T1 pushes 650 cubic feet a minute which was OK for a 50HP engine in a bus. The fan on a T4 engine pushes 800 cubic feet a minute, and when fitted to a T4 car would cool a stock 2 litre 90HP engine, or a 70HP engine when de-tuned in a bus. Even with a 1641 I can push it to the point where my full flow with off board oil cooler makes a difference . I run mine at 65-68 GPS mph or 68-73mph on the clock with the RPM around 4200. I do keep watching the Air Fuel Ratio so that it tends to run rich with foot hard on the floor and leans up when you let off to try and stay cool. It is scary watching the numbers, just how bad a carburettor is at getting the mixture right. Although a progressive carburettor with five different jets and three transition zones is asking for trouble and I just cannot imagine somebody ever being happy with one out of the box.... Inside the budget of £2000 starting with a running T1 would be a 1915 stock stroke DIY engine - machining done professionally - assembled DIY as time is the expense in engine building and doing it properly takes time -- but as they all say a 1776 is probably the best engine to avoid overheating problems with performance. It is probably worth going for a ride in some different engined busses before committing a load of money to a project that may well have a cheaper resolution. Like getting the existing engine to run better. .
What kind of AFR range do you get with the carb? On the FI I'm currently 15:1 leanest (not running fuel cut on overrun yet) the and 13:1 full throttle with the VE map sorted. Control is really accurate even without closed loop operation. I'm trying to aim for cool running, but run too fast, long gradients or keeping up speed into a strong headwind and temperatures do rise.
Overheating in a T4 is talked about a lot, but seems to come in the main from questionable machining (especially the preparation of a set of cylinder heads) or the use of poor quality replacement parts. Lots more talk though about the stock T4 being pretty indestructible as long as they are treated with reasonable care/maintained/built. Looking at the maths, I should be able to source a turnkey T4 & 6 rib box for around £1,300, plus £500-600 rebate from selling my stock T1 as turnkey, meaning £800'ish, then tuning/servicing, machining (if needed) the T4 say £500-700 and then fitting - looks like an all in cost of approx £1,500. I'd be happy with that for a bit more power and grunt than the current stock T1, whilst being under budget.
This guy seems to talk a lot of sense in regards to vw engine common topics - found this article really interesting on servicing and tuning, especially as he keeps things simple: http://haysvwrepair.com/how-to-do-a-real-tune-up-on-an-air-cooled-vw/
An unknown 6 rib box is absolute minimum £600 now. Most are more than this. Can you really get a decent turnkey T4 engine for £700? I got that for a 1600.
You've probably right, just been looking around online and asking locally and seen what's sold within last 12 months. If the T4 costs £1,000 and I can get £700 for the current T1, then the final figure of £1,500 wont be far out - say £1,500-1,700 hopefully seems doable.
I think you'll be fine if you buy a decent T4. If however you end up needing machining / new parts etc you'll spend a lot more I reckon.
I agree and will spend time looking for a running T4 and hope the costs don't spiral thereafter. This is where upgrading the existing T1 to 1776cc with a decent engine builder may prove a safer bet. Pay your money take your chance with both options........
A lot of overheating discussions and the use of external oil coolers are because of higher power engines. Increase power and you increase heat if you use the power over long distances.
Hopefully keeping the T4 stock and servicing/tuning will limit the potential for overheating....hopefully!
Amazing what a T4 seems to be able to take: "Even if you are not interested in "Hopping" your engine for more performance, a stock 2.0L Type 4 will deliver over 40 hp more than the stock 1.6L Type 1. Well tuned you will probably realize 100 hp from the Type 4. If performance is your bag, the Type 4 really offers opportunity. For example, I started with a 1.7L and used 96mm Cylinders. This gave me a bit over 1.9L with a stock stroke. I am running dual 44mm Weber Carbs, Centrifugal Distributor, oversize Valves, Electronic Ignition and a few other goodies. It's in a 1975 Beetle and I have no problem eating Mustang 5.0L and other supposedly fast V8's for lunch, and the engine stays together. I have had it on the road for 3-years and my Valve Lash has never changed a bit. To make the same modifications on a 2.0L would yield close to 2.5L in displacement with its longer stock stroke. That's a whole lot of Type 4 beef, and it will still be rugged and dependable! If you really want to push the envelope of performance capability, the Type 4 can be pushed all the way to 3119cc displacement, as Cylinder Kits are available up to 105mm and Stroker Cranks up to 90mm stroke. Given its ability to cool much more efficiently, you can boost the compression ratio for even more power boost. Also with the Crankcase construction and material, the Type 4 will tolerate much higher temperatures and RPMs without being damaged. This is an area where the Type 4 really outshines the Type 1."
Tuning a Type 4 for a light car like a Beetle is easy as you can get good top end power, as this guy must be getting with twin 44s. It's harder for us camper owners as top end power alone isn't enough, we need torque as well, especially if you fit the longer box.
Thanks - hadn't fully appreciated the importance of the need for torque over HP and the pitfalls that come with trying to get there! Guess this what comes from dragging a 30-40 year old vehicle into the 21st century - fun trying though!!
Have a look in Modified Shizzle section, you can see Torque vs. Power thread, my 2056 build and Zed's build with dyno charts.
If you double that number it will be more like it .....£700 gearbox ....possible rebuild ...£1k turnkey T4 possible rebuild ,clutch carbs and all the missing bit 2k
Just started putting some numbers together re T4 2lt stock v T1 1766cc upgrade - just ballpark figures to date. Difficulty with the cost of the T4 option with 6 rib, is the question mark over the rebuild or not and I wont know until the garage have assessed them. I'm hopeful of the lower numbers but realistic that they may be higher and closer to my £2,500 top end budget. I'm also going to spend time looking at the T1 costs and upgrade of existing 1584cc built by a reputable builder. I'll exhaust the options before making a decision.
