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Mats
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Re: most reliable way to get a 330-350HP motor

Post by Mats »

Greg Gordon wrote:Hey Mats, I was not making a case for supercharging vs turbocharging, I am making a case for forced induction vs normally aspirated. The limit of 1.7 liters for turbo cars makes my point exactly.

Mats, we all know you are a forced induction guy. Don't even try to say you are going to build a NA motor to try and win :)

I picked that video because it's late in the season and Han's car was further developed, but even in it's first outings it was a killer down the straights.


Niclas' car is certainly fast and competitive around the course, but Han's pulls away from it easily on the straights, even when exiting the corners at a lower speed.

Hehe, yeah I know. We do agree but I just wanted to point out that fact so people could make a desicion based on the correct info. :)
My choise for a turbo engine is quite simple, we all know that the torque from a boosted engine easily can destroy the gearbox, with a turbo you can tailor where you want the torque so just bleed off the exhausts in the mid range and make it count where you can turn it into speed instead of destruction. ;)

But in this case I agree with all of the above speakers, first figure out what you want, keep it as simple as possible and then just drive/enjoy! No 24v in the world will make you happker then a 12v unless it's normally aspirated and all the 3.2 cranks in the world won't change the fact that a well built 2.5 supercharged is more then enough to break the gearbox... Everything over that is just bragging points for ego. And it comes at a huge cost in terms of build time and reliablity.

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Greg Gordon
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Re: most reliable way to get a 330-350HP motor

Post by Greg Gordon »

Mats wrote:
My choise for a turbo engine is quite simple, we all know that the torque from a boosted engine easily can destroy the gearbox, with a turbo you can tailor where you want the torque so just bleed off the exhausts in the mid range and make it count where you can turn it into speed instead of destruction. ;)
That is the big advantage of a turbo. It can vary compressor speed independently of crankshaft RPM and thus vary boost throughout the rpm range. This advantage is rarely brought up in supercharger vs turbocharger arguments, which is strange because it's THE big advantage of a turbo.

All that said, the supercharger has advantages too. I really think they are so close it's really a matter of personal preference. I like the supercharger better, at least the Roots and Lysholm types.

Then again, I own two hot turbo cars, a Hyundai Genesis coupe R spec with 274hp, and a Fiat Abarth with over 190whp so I love turbos as well. Both cars are very quick and almost dead even with each other in a drag race. Both will lose to the supercharged 2.5 GTV6. The old Alfa V6 is pretty impressive, the Hyundai engine is smaller, but 30+ years newer, 16 valve, and has a modern dual scroll turbo with 15psi. The old Alfa with a now outdated supercharger and not even 10psi still beats it.

OK, so the Hyundai turbo vs supercharged Alfa isn't even close to apples to apples, but it does show that even older superchargers can push the Alfa V6 far enough to be competitive in the modern world
Bareass
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Re: most reliable way to get a 330-350HP motor

Post by Bareass »

my 2 main reason for prefering supercharging over turbo charging are, not changing the exhaust sound, and less plumbing.

i could always just through in the 3.0 24v, but if i'm going to crack it open to clean up, i might as well do some work to it, right?!
the other advantage to boosting, if i get the compression down enough, I can get out of the interference range, which will save pistons, valves, and heads in the event of something bad happeneing!

i've come to the conclusion that i want to stick to the current bore of the engine. this will keep my hands out of the top end, and keep things a little more simple.

so my choices are, 3.0, or 3.2, either NA or Supercharged.

who has a source for 3.2 cranks, pistons, and rods in North America?
'84 GTV6 w/3.0
3.0L 24V engine stand!
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Re: most reliable way to get a 330-350HP motor

Post by kevin »

The exhaust sound is gonna change even going big bore so that should be least of your worries . I think you have enough info now to make decision . Don't under estimate the amount of work putting a 24v in . Its far easier work to supercharge the 12v . Again is a budget a constraint .
On the gearboxes , I don't believe I have heard of a 75 3.0 box breaking as it has a much bigger pinion than the 10/41 and the smaller 10/43 . But you gonna need good power to pull hard with that box .
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Re: most reliable way to get a 330-350HP motor

Post by Bareass »

the engine should be close to just a drop in. it is already modified for rwd, and was fitted and running in a milano.
the engine is already paid for, that is why i want to use it!
'84 GTV6 w/3.0
3.0L 24V engine stand!
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Re: most reliable way to get a 330-350HP motor

Post by kevin »

Ok if you that far then supercharge the 3.0 24v as is and run at low boost as you could easily equal the power of a 3.7 . I heard supercharges are pretty cheap in the states . I actually got more power out my 3.0 24v with very little work over my gta which was standard . So then no nead to search for a gta crank and pistons . Try be the first to supercharge a 24v in a 116 GTV . I don't believe it been done before . Use gregs book for your pulleys sizes etc . Post plenty pics , ha ha
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Re: most reliable way to get a 330-350HP motor

Post by Greg Gordon »

Bareass wrote: the other advantage to boosting, if i get the compression down enough, I can get out of the interference range, which will save pistons, valves, and heads in the event of something bad happeneing!
Good thinking, but no. The compression ratio has little to do with it. I could make a 9:1 interference piston, or a 9:1 non interference piston. It all has to do with the valve cut outs.

The problem is, to make the valve cut outs deep enough they end up in the top compression ring's groove. Obviously that's no good so to fix that we have to move all the rings lower on the skirt. Then, the oil ring ends up in the wrist pin's hole.

That creates two new problems. First the wrist pin and oil control ring must be retained in place without the use of a "C" clip. Not a biggie. We use teflon buttons for that, they last forever and are really easy to put in, easier than a "C" clip. Second, as the piston rocks it can prevent the oil control ring from doing it's job. This was a tricky problem to solve, and probably one of the reasons the factory never made a non interference piston for this engine.

It took us three tries to get the right combination down, but we did it. That means three complete tear downs of a 3.0 and three different sets of rings tried, so it was a lot of trouble.

The next issue you run into is dome height. Too high and it interferes with flame travel, probably not a really big deal but still something we thought about. It turns out that with a 3.0 liter engine 12 valver, with valve cut outs deep enough for no interference with stock cams and flat top pistons you end up with 8.8:1 compression. Hence that's our standard 3.0 piston.

The 2.5 is a lot trickier. Our current design has 8:1 compression, but allows some pretty hot cams and is still non interference.

Greg
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Re: most reliable way to get a 330-350HP motor

Post by Bareass »

i didn't think the valves dropped that deep.
well there goes that reason! lol

Greg:
what compression ratio would you run on a 3.0 24V if you were supercharging. i'm thinking Low boost, just to get the low end torque where it should be.
'84 GTV6 w/3.0
3.0L 24V engine stand!
Greg Gordon
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Re: most reliable way to get a 330-350HP motor

Post by Greg Gordon »

I haven't worked with the 24 valve engine, but if I did I guess my plan would depend on budget. If I was working with a low budget (I often am) and the limitations of the stock transaxle I would just keep the stock pistons, with good intercooling and water injection I would run 7psi and it would be fine.

Now, in another world, large budget, front mounted gearbox, strong differential, I would drop it to 8:1 and run at least 15psi.

Greg,
www.hiperformancestore.com
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Re: most reliable way to get a 330-350HP motor

Post by Bareass »

i think this sounds like a plan, i can save the money on boring or going 3.2 and put it into the supercharger!

its time for the research to begin, if anyone has good supercharging tips, please feel free!
'84 GTV6 w/3.0
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Greg Gordon
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Re: most reliable way to get a 330-350HP motor

Post by Greg Gordon »

Well, I have written a book on the subject. What is it you want to know?
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Re: most reliable way to get a 330-350HP motor

Post by 75evo »

Greg,

Do you have a sprintex for the V6?
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Re: most reliable way to get a 330-350HP motor

Post by Greg Gordon »

Nope, I barely even have it on the 4cyl. I don't know if there is a market for it on the V6. The 335 could deliver 500hp no problem, but how many of these cars are around? How many have front gearboxes?
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Re: most reliable way to get a 330-350HP motor

Post by kevin »

Bareass , best tip ever is to order greg gordons s book on supercharging . Excellent read and you have enough info to do your own conversion with the correct pulley sizes etc
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