supercharching options

Norwood has a turbo "kit" that they sell for around $7K including a Kevlar clutch - another $3K for the intercooler ( I may be off on the pricing). I believe they have installed about a dozen or more of these units. From my reading / research, the turbo will give you about 400hp. Because of the heat factors, I don't think I would run the turbo without the intercooler, but that's just my opinion.

As per performance, the SC would appear to give you more power thoughout the rpm range, while the turbo would be more geared to come on around 4K rpms. As stated to me by some very knowledgeable individuals, they both have their plusses and minuses. For pure track usage, I think the turbo may be the way to go, so long as you keep the rpms up. I'd hate to be in the middle of a turn and have the turbo kick in. Perhaps those with a turbo already installed could post their experiences and thier opinions.

Anyway, I look forward to what you come up with. As mentioned before, I plan to boost my car. I am tired of getting my doors blown off on the straights.

By the way, Mark E is using the Lysholm-type SC on his 500+ HP 308QV.

 

You'd probably want what they call a zero drive, so figure $2000 - whipple gives list price on their web site, you can save about 20% shopping around. Autorotor is very similar in performance and can be had a bit cheaper, around $1400 last I checked.

A working used eaton roots type off a buick or t-bird goes for about $200 on ebay. You can add 100 hp with that without an intercooler. I got 300 rwhp with one (an mp90) on my QV, so 360-365 crank. Not bad.

If you're really trying to save money, the efi can be done with a $400 megasquirt....I think it's worth spending the extra $1000 to go to haltech, but a MS will work. I think Tilman is going to give it a try, but I don't know how far along he is.

With a positive displacement SC, the total boost that can be had in based on the size of the blower, the power curve will pretty much match the NA curve. For example an eaton MP62 will yield a max of about 5 psi, an MP90 will yield 10 psi at the same drive ratio, but the shape of the curves will be the same. Or slow the MP90 down to get 5 psi, and the 62 and 90 dyno lines will nearly lay on top of each other. They are pretty easy to setup and get right.

A centrifugal compress is another animal, turbo or SC. If you size it large enough to make the boost you want on top, trying to spin it up to make boost down low will make it surge and shake itself apart. Size for boost down low and it will choke and become a follow restriction on top. It works better as a turbo than a SC because the compressor rpm does not very linearly with engine rpm....the turbine can bring the boost up staying just above the surge line, then the wastegate can slow it down enough on top to prevent over-boost. When you try to run it as an SC, you can only control 1 of the 2 critical points. If you try to bring the boost in on the surge line, you will over boost on top and that’s no good. So you end up controlling the boost pressure on top, but then the boost comes in very late. It works but it's not great. You can add a pressure relief valve, but that is really in efficient. Paxton lets the compressor slip to limit boost, tha'ts about the best you can do short of adding a CVT trans...but then it would only be as good as a turbo, so I think it would be better to just do a turbo to begin with.

 

For reference, I could justify up to a total of $10K for a EFI/supercharger upgrade including installation. Beyond that, as much as I love my 308QV, I'd be thinking of getting a different car. I'm not interested in a turbocharger setup at this point.

 

That would easily put my Euro QV where I want it. It dynos out at 183 rwhp. Another 120 rwhp would make me ecstatic.

Mk e, that was a stock US spec QV engine wasn't it?

Was this the setup that you were running non-intercooled at 10psi boost? How marginal were things at that pressure? I was following your thread, remember you having spark plug damage due to detonation, but did you then come up with a better mixture map that avoided the detonation?

 

Yes, stock QV- mostly. It had total-seal rings and a bit stiffer valve springs, neither of which are required...they were cheaper and better than OEM, so I used then.

I always bought 93 or 94 octane and it worked. To get to 10 psi I had the blower ratio at 2:1 overdrive, so at 7700 the blower was at 15400....the book said redline was 14000. The intet air temp was over the 260F limit of my temp senor. It worked. I had a couple injectors fail, which caused detonation and damaged the plug, but a brand change fixed it. 8 is fine, 10 is on the limit. Honestly, I'm not sure there is more than 10 or mayby 20 hp difference between 8 or 10 with a roots blower, it's making more heat than boost up there.

 

Hi gang,

The Whipple isn't on Rachel (my Mondial t Cab.) but is installed on my 95 GMC pickup. I can only imagine what that very tolerable whine, connected the the Italian Opera music produced by Ferrari, would sound like!!!!

Come to think of it - - I believe someone posted a pic of a Whipple (like) charger on - - I think it was a QV Mondial - - not sure - - . Anyway, sure sounds like fun.

Cheers, Hank

 

Let me help you with that Hank .
http://mywebpages.comcast.net/markeberhardt/MarkFerrari.mpg

 

On the 308s, there's a pocket to tuck it into under the rear bank, between the headers & the sump. It's a counterpart to the space the alternator fits into. Altho the half shaft makes it a bit narrower, & the differential constrains the depth. There is a similar space on the other side of the differential. Believe that's where Mk e installed his first supercharger. The Mondial has that same open space, so all 3x8s could share a common set of mounting hardware.

Given the general concerns about cam belt lifetime, adding extra load on a camshaft doesn't strike me as desirable.

Also, there have been reports of air pump bearings seizing & breaking camshafts with predictable results when the adjacent piston went up...

Mk e,
Wow!!! 260F is a lot hotter than what my Rx7's turbo puts out into that toy stock air-air intercooler! Altho, I'm only running 6psi boost because I haven't had time to mount my home brew boost controller, but 8 was as far as I was planning on taking the boost up to with the stock injectors & fuel pump. At 6 psi, the outlet temp is only about 40F above ambient. A plus for a rotary style compressor...

 

Roots blowers are not for high boost, not bad at 4 or 5, but 10 was asking a lot with no intercooler. The discharge on my lysholm at 20 psi is over 300F....the intercooler is required.

I looked at other mounting locations, but both of my set-ups were on top with custom intakes...I like the way it looks up there.

 

I'd probably be happy with 300-320 at the crank. I'm just looking to be able to keep up with the mini vans.

$10k is probably my limit installed or $7k uninstalled.

 

Fitting a supercharger will be a big hassle on that car. I suggest just mounting small turbos onto it and calling it a day. Try and make some kind of adapter kit to bolt onto the factory manifolds so you dont have to make a new set adding to the kits cost. Personally the cheaper route to go would be doing head work and some bolt ons like headers. You could port and polish the heads, mill the head down to raise the compression, even do a upgraded cam. But to do forced induction the proper way its going to take alot of money and replacing alot of parts. If you have any questions on the head work send me a pm or email.

 

I believe that with a propperly done set of heads elimination of the CIS, free flowing muffler/Cat, and maybe more lift in the intake cam a QV engine will jump to 335-345 hp. With the compression bumped, rev limit raised and bigger cams to match 360-380 should be about right.

...But that's not cheap either. Just parts for a stock rebuild are about $4000. A top shelf head job is going to fall in the $2k-$4k range. EFI or carb conversion about $3k. 350 hp is going to cost $8k-$10 no matter how you go about it. The exception being a used eaton and MS EFI....then with all the machining maybe $4k-$5k.

I'm in the middle of having my heads done so I'll post something with results when it goes back together....it may still be awhile though, my has me on a yard make-over including a new pool/patio so money and time are just a bit tight at the monent. Hopefully before summer ends.

 

Scott,
How much hp are they making? That'ss what decides if the plate will bottom and the spring needs to be jacked up. I'm guess it's in the same ball park as the 308.

Also, did he tell you what he is controlling the mixture to? CIS is design to be around 13.7-14.7 I think. For 5 psi you'd want to be more like 11.0-12.0 I'd guess, but not cruising, then you'd want 13.7-14.7 again. I don't think CIS can do that, and is part of the reason the CIS cars had such low compression (too lean under power)....but I may be wrong. You definately could just run say 12- all the time and just know the fuel milage will drop 10% and the cat should come off or it will fry.

 

Which BOSCH book? I have their entire CIS Tech training series, if it's one of them, would make you a copy.

 

Thanks.

My QV at 10 psi from a roots blower maked 300 rwhp, or 360 crank. That would be about 7 or so from a screw or centrifugal type....60 more than the 928 graphs. Be carful. A 2v injected would be less, probably about where the 928 graphs are.

I'm not sure where the 9psi number for the head gasket comes from, I'm hitting over 20 psi with the stock head gasket without a problem. A 308 is good to 15 psi without doing a thing, provided the mixture and timing are right of course.

 

I hate to be a wise guy but you're either going to have to observe your CIS air vane with the car on a chassis dyno or ride on the back of the car with the engine cover off while a friend drives (not recommended) to get a "real world" idea of how much the vane moves at various engine speeds. You will find that It requires significantly more air and fuel to spin a loaded engine up to 5000 RPM than an unloaded one. In other words, when the car is driving down the road at 5000 RPM the vane will move much farther than you were able to observe with your test.

Your idea of mocking up a supercharger out of styro-foam to check fit and placemennt in the engine compartment is an effective one that I 've used many times. The supercharger manufacturers are usually willing to provide dimensions. I use 2" thick rigid pink styrofoam insulation board. Once you have your pieces cut out on a band saw or with a sabre saw and glue them together, you can paint your shape with shellac or even latex paint so that bondo will stick to it to fill out and smoothen your shape if needed. This method is good for making complicated one-off air ducts too. If you apply a release agent you can cover it with fiberglass and hollow it out after the resin cures.

Wil