Group Buy: 3x8 Throttle Body Mod + Plenum Mod

I know, I know, bad link. I added pics of the TB to my last post.

 

first, I said "might even bolt-on"...it might not. I'm sure it can be made to fit easily enough. boring out the plenum should be about a $50-$100 job, modding the new TB to fit about the same. Any machine shop should be able to do the job...maybe Verrel if you ask nice? Or I can do it for you I guess.

You probably don't nee to bore the plenum to get most of the gain, a little light grinding with a dremel should get you most of the way there for free. The flow restriction is usually the throttle plate, not the bore, so just smoothing the transition between teh 2 bore sizes should do the trick.

If you don't have lambda, then the $52 kit should do the trick on the mixture....but don't forget about tuning time if you can't do that yourself....although I bet you could if you set your mind to it.

 

Steve,

If none of it works It's all Marks fault.

 

Okay, from Kieth Bluemels book....

timing data of camshafts.....

single distributor GTB/S (carbed) euro?
intake opens/closes 30*BTDC/50*ABDC
exhaust opens/closes 36*BBDC/28*ATDC

twin distributor (carbed) US?
intake opens/closes 34*BTDC/46*ABDC
exhaust opens/closes 36*BBDC/38*ATDC

Notice the duration is equal on the intake cam, just the US car has the intake advanced 4*, and the exhaust cam on the US car has "more" duration of 10* So why did the US car make "less" power?

Now the CSI cars...

308 GTBi/Si (EU)
intake opens/closes 16*BTDC/48*ABDC
exhaust opens/closes 54*BBDC/10*ATDC


308 GTBi/Si (US)
intake opens/closes 16*BTDC/48*ABDC
exhaust opens/closes 50*BBDC/14*ATDC


Nothing changes a lot after this, up through the 328, however the US QV 308 exhaust timing goes to 40*BBDC/14*ATDC, so it lost even more duration there. My sons Mazda, which has electronic fuel injection, is even more rediculous. Intake was at 15*BTDC, and exhaust closed at 5*BTDC. Yes, BEFORE. Yet cars back in the 70's with electronic injection, had timing simular to the carbed cars above. The narrow overlap is for emissions, but really knocks out performance. If you can spread that back out, until the CSI senses it, I would believe you would get some real power back.

The carbed cars have 16* more duration than the injected cams, so they are milder, but you still have room to play with. I would try, if I had one of thesecars, something like ....

intake opens/closes 25*BTDC/39*ABDC
exhaust opens/closes 35*BBDC/29*ATDC

What this is doing, is advancing the intake cams 9*, and retarding the exhaust 15*. This would widen the overlap from 30* to 54*. I have read some who felt a US carbed intake cam would work, but that isnt a cheap fix. Cheaper would be to have your injected cams reground to a different profile. Keeping the stock cams, you could easily return the engine to stock condition, and it really costs nothing other than timing belts. Someone else with more knowledge of valve timing and how engines respond to it, may have a better starting point than I show above. But I seriously would try altering it in some direction.

 

the Edelbrock TB is for 5.0 Ford Mustangs, Hondas and Acuras, the Ferrari TB has various vacuum lines and is a bit different than it, you could maybe make it work but I think it would be easier to mod the OE TB.

Note on Edelbrocks website they state the stock 5.0 Ford motor has a 65mm TB and by adding the 70mm Edelbrock TB it gained 10HP, I had a 5.0 Mustang in the early 90s and they had 225hp motors so 10hp gain is not bad.

http://www.edelbrock.com/automotive_new/mc/efi/throttle_bodies.shtml

 

This engine is EFI however, and not CIS.

As much as some don't want to admit it, the BIGGEST issue with these engines is the CIS itself. There is no real point in trying to improve the performance of a CIS system. They were implemented for the sole purpose of meeting emission regulations - nothing more.

As an aside, consider the difference in performance between the 348 and 355. Essentially the same engine, but an extra valve and an extra 0.1L, yet almost 20% more BHP. Note that the 348 was the first V8 from ferrari with true EFI. As the company gained experience with it, they realised they could extract extra power by tinkering with cam timing and other mechanical parameters, and use the electronics to keep the thing emissions legal.

So, IMHO, to get the most out of a 308 "i" model, the first thing is that the CIS must go. It doesn't matter if you go carbs or EFI (unless you live in California ) Once this has been done, you can liberate extra power and torque by changing mechanical parameters - camshafts, ignition timing (easily handled with EFI), increased CR, porting heads etc etc. Which way and how far you go depends on 2 things. The first is $$$ and the second is $$$.

If it were me (and it isn't) I'd be leaving the basic engine as is, going to EFI with the standard manifold and TB, and then if/when money permits, adding either a small scroll supercharger or a turbo system. There is no reason this setup running low boost of no more than 6psi can't produce around 300BHP. This is well within the capabilities of the engine, gearbox, and most drivers.

From here, the jump to 400 is just an intercooler, and increase in boost away. The next level of real expense of course is uprating the brakes and suspension to safely handle the extra power. Beyond that, rumor has it that the gearbox can get unhappy and things may break, although there are many people running 450+ HP with no gearbox issues.

If money is a real concern, then one could try to use second hand parts. I suppose 2 sets of Toyota 4AGZE (supercharged 1.6L 165 BHP) ECU's, injectors, sensors etc could work nicely. I am unaware of a cheap source of superchargers however. Perhaps a Buick V6???

Anyway, I really think that if one is going to start deviating from the way Ferrari built the car (nothing wrong with doing this) then there is no need to continue thinking and paying Ferrari-type money. Take a look at what some of the ricers are doing with their cars on a budget. When money is limited, ingenuity often flourishes.

Dave

 

People keep saying that CIS is awful...not meant for power...Yet the Ferrari Boxer, Lamborghini Countach, and Porsche 930 Turbo all ran with K-Jet (CIS).

TECHNICAL SPECIFICATIONS
Lamborghini LP5000QV Countach


ENGINE
Type 60° V12
Longitudinal, Mid-Mounted
DOHC per bank
Valves 4 per cylinder
Bore/Stroke 85.5mm x 75mm
Capacity 5,167cc
US Spec Fuel System Bosch K-Jetronic Fuel Injection (CIS)
Max power 420bhp @ 7,000rpm
Torque 340 ft/lbs @ 5,200rpm

With Euro Spec Fuel System 6 Weber 44 DCNF
Max power 455bhp @ 7,000rpm
Torque 340 ft/lbs @ 5,200rpm

_____________________________________________


Ferrari Boxer
4942cc displacement and 9.2:1 compression, the 512i received a Bosch K-Jetronic injection system that actually provided the full 340bhp of those originally Weber carbed 512's and at 800rpm less (6000rpm).
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the countach has CIS injection but really uses two, one for each bank of cylinders
this is a pic of a costumer's countach
i don't have a pic of both CIS systmems but you can see that the gas hoses that go to the injectors come from both sides
so two systems have LESS restriction than just one therefore more power!
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That's about 7% more using carbs. The 930 does not count as it is turbo'd, and if the CIS fuel distributor is calibrated appropriately, then it can handle the extra fuel demands. I suspect the 308 distributor is not going to handle any significant boost without potentially expensive.

As for the BB, in "Ferrari" by Lehbrink and Schlegelmilch, the BB is listed at 360 and the BBi 340 (page 264). No doubt a dozen different books would yield a dozen different numbers!

Anyway, these cars HAD to use CIS to meet emissions laws. I am certain that if they didn't have to change to CIS, they would not have done so, and the power output would have been greater.

Dave

 

The evidence points to CIS (K-Jet) being able to handle high horsepower. It may not be the best, but spending $5,000 to junk it might not be the budget way to go.

CIS can deliver the fuel. Spark can be boosted with a better coil pack, better plug wires (or here's a thought, coil over plug), and better spark plugs (Bosch Platinum +4 plugs are better today than what was available in the 1980's).

There are some timing advance and cam profile options, too.

That leaves air. If performance is your concern, then air can be increased through the CIS by eliminating the sensor plate...the budget way to do that (though of course there are other technically superior options) would be to connect either the CIS throttle flap or cable via a spring (to give a tiny delay in order to help give the system time rather than just a pure throttle position - more closely approximating the air flow metering) to the CIS sensor plate lever.

Obviously whatever air passages could be machined, should be machined, and perhaps a bigger throttle body or even an air filter mounted almost at the TB itself would help a bit, too. I'd suspect that you could trigger the Auxilary Air Regulator at Wide Open Throttle for a bit more air, too.

You aren't going to get great throttle response or gas mileage out of such a system, but you should be able to get more performance out of the 308's existing CIS without killing a budget.

Beyond that (and still on a budget), you'd probably want to look at dropping weight, better exhaust and overall exhaust plumbing/heat insulation, and NOS.

Also, AEHaas has put forth some pretty compelling evidence and arguments that a substantially lighter weight engine/tranny oil will bump up HP by reducing internal engine friction. Royal Purple and Redline come to my mine along that line of thought.

 

yes

Yes , for $2000-$4000 you can get any cam you want, but what will work with the CIs system is quite limited. so you can make 10 or 20 hp adding cams to a CIS engine, and 50 adding them the a carb or EFI engine.

Air is ALWAYS the limiting factor....that's why in racing they ALWAYS limit boost and displacement. Putting an air restrictor (CIS) on the engine is not a good way to make hp. The new BWMs have gone so far as to remove even the throttle plate from the air passage way to reduce restriction. Most racers pull the MAF sensor off and go to a MAP sensor, it's not quite as accurate, but it's less restrictive so they make more hp. You can't make hp with a restriction in the intake tract....and you can't connect the mass flow lever to the throttle cable, I thought that was clearly explained already, but I'll try again. With the engine idleing, the throttle can be fully open and there is a fuel flow rate for that condition. With the engine at peak hp rpm and the throttle wide open there is a fuel flow requirement that is much higher than at idle. The mass flow plate allows the system to know the difference. Hilbore type systems use a mechanical positive displacement fuel metering pump driven off the crank (so fuel flow is proportional to rpm)to allow them to know the difference. So, I'll say for the 3rd time, the engine will not even run if you simply connect the mass flow lever to the throttle cable, you need to add something to replace what you're removing for it to work.

Sure you can do all that. Porting the heads costs about $2000 plus the remove and install costs. There is tons or labor in improving air flow, but it certainly can be done. I gues to get 20-30 more hp out of a CIS engine you'd need to port everything and cams, so $5000-$7000, not a very good return on a hp/$.

Asked and answered. In general, cutting weight is about the most expensive way to increase performance. The exception of course is when you decide you can live without something like your spare tire, AC, sound deadening(although ferrari already decided this one for you). The euro bumpers kind of almost make sense, but you lose crash protection. So yes, there is about 200 lbs (6% improvement) that can be had for under $2000 if you can live without the stuff you remove, and most of us can live without some of it. After that it gets very very expensive to remove weight.

AEHaas's advice is going to result in a blown-up engine, it's simply terrible advice. To be fair, he says clearly how he drives his car, and under the conditions he describes, a lighter oil will work just fine, as he says it will. BUT if you decide to go ahead and stand on the the power, the engine will melt with thin oil in it. That said, synthetic oils are better than standard oils and you can get a lower cold viscosity, so 0w50 instead of 10 or 20w50 will add a very little bit of hp, 1 or 2 maybe around town...but on the track when the oil is full hot, it will add nothing. I have seen different brands act differently on the dyno, but normally that is a synthetic/standard thing and the synthetics win.

So, is the horse dead yet?

 

Still BEATING IT! The poor little Cavallino
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I agree with Mark concerning the oil advice AEHASS has posted, I have mentioned it in his oil threads as well, don't go to a thin oil unless you want a seized cam bearing or mains or other massive failure if you drive your car hard.


Back to the original question yes CIS is very restrictive which is why CIS cars require a mild cam because CIS is very sensitive to pulsations in the intake system and requires cams with little or no overlap.

Looks like we'll just have to wait and see on the dyno numbers here for the true results.

 

I thought the original point of this thread was inexpensive and simple modifications to CIS cars to simply boost performance a bit and keep the appearance of the car and its engine basically stock. No $5000 turbos, no $3000 electronic injection setups, etc. If I missed that premise, I appologise.

Ferrari certainly understood electronic injection long before they used this CIS system. CIS was used primarily because it was a simple and extremely reliable system. Set it, and forget it. Also, Ferrari didnt HAVE to use it, they just chose it over electronic probably because it was possibly cheaper, but still far more reliable.

I also agree with the oil issue, keep up the viscosity if you want to keep your motor.

Change the cam timing, ignition timing, blow out the cats, and find a way for it to get some more air, and I think you will see a big improvement.

 

Just about this time last year I had a conversation with my mechanic about viscosities. Coincidentally he had in the shop a 308 that lost a main bearing in which the owner had gone to a lightweight oil a couple of weeks prior. This gives some validity to the above quotes.

Those lightweight oils may be fine in newer engines. Older engines that were made a decade or more before these oils were developed would be better off staying with oils that they were designed to use IMO.

 

If others follow the advice for thinner oils I think you'll see a few Ferraris down the road with major engine failures or needing premature rebuilds in the future, I feel sorry for the next owners of these cars as well.

Like the old saying a little knowledge can be worse than none, might as well put some sewing machine or 3 in One oil in your motor as it flows better and prevents startup wear.

 

So, a 308 owner should avoid the 0W-whatever or the 5W-whatever always. Even in the winter.

I was actually thinking of switching to the 5W blends in Dec thru Feb. I guess I won't now.

 

No, 0w or 5w are fine, just stay away from anying ending with a number smaller than 40

 

You're right and I agree with what you're saying. It's the viscosity that matters and as long as the pressure is up in the normal range, you can be sure that the viscosity is adequate regardless of what oil you put in the engine.

My point was that if you put Xw-40 in the engine, you don’t need to worry about anything, your engine will be safe under all but the most extreme conditions…. although literally your mileage will vary. Running thicker oil than required will waste a bit of fuel and reduce engine output, but it is safe even if the weather was warmer the normal for the season and you decide to drive harder than normal as a result.

On a side note, I try to stay away from the 20w50 and look for at least a 10w50. Castrol has a 5w50 that is pretty easy to find, so I usually use that. The lower first number doesn’t do any harm and gets the oil flowing faster, reducing start-up wear….which is about 90% of total wear for a street engine.

 

I am not so convinced on the thinner oil start up wear theory, thicker oil will stay on the parts longer and keep the protective film on it, thin oil will dissapate off the parts, true if you let the car sit for an extended length of time most oil will be off the parts and thinner will flow faster but cars used regularly it won't have this issue. No matter what its going to take 3-8 seconds for oil pressure to build and circulated thats where the wear is, if you still have a oil film on your bearings and other wear parts it will protect them, a thin oil that has drained off with no film will not.

I prefer Valvoline Racing 20/50, it has lots of nice additives as well.