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Discussion in 'Vintage (thru 365 GTC4)' started by Italian Tuneup, May 6, 2020.
what type fuel are you using on the dyno?
Ed: It depends on the intended motor usage. For vintage race engines, we test with 110 octane race gas. For street engines, we use normal pump premium, which here contains up to 10% ethanol.
do you see much of a difference in hp between the two fuels?
what settings do you have to change if switching fuels? jets? float levels? timing? etc
Thank you gentlemen, for setting me straight.
I thought I had read in some places (perhaps incl. parts books ?) something about different compressions and/or designs numbers on pistons, but maybe I misunderstood it all.
Goes to show again, one shouldn't trust everything that's printed. From now on, I best measure compression ratio myself before touching a keyboard regarding them.
I think Timo remembers correctly and you can find different parts numbers for the pistons, rings and pins for cars with air pollution system. But of course I don´t know if there is a real difference in these parts or just different numbers for the same parts.
Stefan: Are you sure there are different part numbers for Emission Control Pistons, Rings and Wrist Pins? My parts books DO NOT show any changes in these parts for Emission Control engines. However, I did further research and need to correct my previous post. By September 1972, there was a new part number for the pistons. While the rings appear to be the same, they now pickup a "Ferrari" part number in addition to the Borgo number. The item that changes is the wrist pin, going from a 365 California (217B) pin to now having a Daytona (251) part number. My guess is the new piston part number only reflects the pistons now having the later wrist pins, as they came from Borgo complete with rings and pins.
Stefan, while I greatly appreciate your efforts to support my recollections, I’m more than willing to bow down for Dyke’s experience as it’s clearly far wider than I could ever hope to establish.
Ed: In reply to your question about dynoing with different fuels, here are some comments:
Overall the compression ratio determines the fuel needs.
Engines from the pre-ethanol era require about 14% more of today's 10% ethanol fuel by volume to equal the fuel of the 1950s-60s. Thus they need to be jetted richer than they might have been 50 years ago. However, generally speaking, Ferrari always jetted their motors fairly rich to prevent burned pistons during long high speed runs, so we find the need to increase jet sizes on pre-1970 cars to be very rare.
Different fuels generally effect ignition timing the most, and it is common to have to change timing when we change fuels. Generally, the 250/275/330 motors on race gas like about 38-40 degrees total timing, not the 42 degrees of the original factory settings.
I found the different part numbers on ferrariparts.co.uk with the addition „for cars with air pollution system“
But again, I have no clue if these are different parts but remembered it when I read your statement. I could not find these numbers in the printed parts book as well.
The engine is run in on the bench with a special oil. Then it gets the 1st service before testing it.
Compression ratio is result of piston and head shape. Since pollution version heads have different part number is it possible that ratio difference (if it exists) comes from heads shape?
If you have a Ferrari motor on rebuild I would consider a lighter weight flywheel/clutch on install. You will likely enjoy this more than fretting over a few horsepower. The motor will "get to the power" sooner.
Different part numbers for the U.S.-market heads are perhaps from air induction modifications rather than combustion chamber shape or volume changes, but again, I haven’t compared/measured to see if any differences exist.
OTOH, quick review of my reference library seem to suggest at least 4 different design (part ?) numbers for pairs of heads ...
Hi all, just a reminder to the Daytona gang that I am looking for a particular number gearbox. Or, if yours doesn't match the engine number, I might have yours! PM if you think you can help or be helped, thanks.
All the best to all and stay safe,
The first time I ran my 308QV on a dyno, it reported ~495HP. There were a lot of initial cheers going around the room, but I was quite sure that wasn't accurate.
It is more likely reason for differences but it is at least technically possible to change CR with head design.
Carobu (no affiliation) dynos many of their rebuilds and Daytonas range from 353 to 459 hp, depending on the state of tune:
Am new to the classic F world. My Daytona engine is being rebuilt as we speak. From reading your posts it seems that a dyno is a must have and I’d be stupid not to have the shop prove to me through the dyno results that they’ve done a good job.
When I negotiated the price for the rebuild I wasn’t aware that a dyno would be essential. The shop has their own dyno facility and says it’s 9k option. What would you do? Break in the engine myself (can’t wait to drive the car that I’ve owned for 6 months) or absolutely do the dyno (and negotiate the price down)?
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9k is ridiculous.
can you have them deliver your engine to an independent engine builder w a dyno?
Ask for an understanding of how 9K is calculated. Perhaps they are factoring in a huge amount for personal liability if something goes wrong. Setting an engine up on a dyno and doing some baseline pulls then taking it off should be no more than 1 day of labour calculated at whatever the shop rate is for the dyno. If you want to get into finer carb tuning and optimizing add a half day (assuming you have the required jets ready to go).
First of all, congratulations on your ride and welcome.
While it is not necessarily essential to have an vintage road engine broken in & tested in a dyno, I’d say it’s an intelligent choice, especially with something as complex and costly to rebuild like the one in Daytona, mainly because it is much easier to address any and all potential leaks or other issues that may show up on a newly assembled engine.
Power output tests are and should be a secondary concern.
As for the cost, while it sounds a bit on the high side, every shop has their own rates and this charge may include other things than just a dyno set-up & operating hours. Regardless, it would still be much better value than spending same, let alone more, on something as silly and useless as, let’s say an OEM toolkit.
I'm going to suggest that none of us have enough information...
Did the previous negotiation make everyone happy? Is your relationship with the builder a partnership? I'm not suggesting that anything untoward happened before, but often very high estimates are based on past experiences or perceptions. Sometimes it's a polite way of saying they don't want to do anything more than the original scope.
a daytona engine rebuild means he is swimming in the deep end already. no good reason not to dyno it.
he should also get an original tool kit while hes spending but they are so hard to find
I have had engines built a long time ago and it was part of the builds but $9k sounds like it includes the Ferrari tax. They should have quoted it up front with the estimate IMO.
Gee do you know of any Ed?