With Pizzaman's tranny delivered, I'm now seriously getting back to work on my car. Finished installing the head coolant pipes & redesigned waterpump body/thermostat housing today, will post pix as soon as I get a chance to reduce them. FERRARI MANUALS ARE WRONG!!! mk e had written me that I needed to increase inlet valve spring pressure because Norwoods has consistently experienced valve float when boost goes much above 18psi. The 'float' is because the boost pressure on the back side of the intake valves has offset so much of the spring's pressure that the valve's action slows down too much. This system can deliver boost pressures up to 22 psi. I was going thru the calculations to determine if I needed to get stronger intake valve springs, or if the OEM springs could be shimmed enough to prevent float. I based my calculations on the spring specs from the QV/328 WSM, & believed them good since the 328 Tech Specs... manual had the same specs. The intake valve is 29mm in diamenter which works out to 1.15 sq. in. 22psi acting on 1.15 sq in will generate about 23 lbs of force that wouldn't be present in a normally asperated car. Ideally we'd increase the intake valve spring pressure by 23lbs to completely offset this increased force, bringing the net of spring + boost force on the valve back to the normally asperated spring pressure. I ran thru the numbers & it looked like I could easily get the 23lbs or even more just by shimming the OEM valve springs!!! However, I wasn't comfortable with this answer so I called mk e to review my calculations with him. In particular, I was concerned because his calculated shim thickness was different from mine. We compared formulas & Mark confirmed that I was performing the calculations correctly. However, He recalled that the Mondial QV manual had valve spring specs that more closely matched his springs than the specs in the QV/328 WSM so he'd used them. Luckily I had all 3 manuals, so could compare them quickly. Sure enough, the QV/328 WSM and the 328 Technical specs.. manuals HAVE SPRING SPECS DIFFERENT FROM THE Mondial QV manual!!! In fact, further checking revealed that the QV/328 WSM and the 328 Technical specs.. manuals HAVE THE SAME VALVE SPRING SPECS AS THE 308GT4 MANUAL! The Mondial QV's valve spring specs are correct, the other 2 manuals are WRONG, they arejust repeating the 2V valve spring specs! Back to work with better data: I just dropped the correct specs into the spreadsheet I'd been using. Intake valve spring pressure at valve closure is about 59 lbs. The spring rate of the combined valves is: 337lb/in. To completely offset the boost would require shimming both the large & small input valve springs by 23 psi/337lb/in = 0.07"[1.7mm]. However, The maximum amount the OEM springs can be safely shimmed is 1.45mm[0.060"]. This shim thickness will increase intake valve pressure at closure by about 18 lbs. 18 lbs won't completely negate the boost effects , but it will mitigate all but about 5lbs of it, leaving about the same additional pressure on the input valve as about 4lbs of boost. I believe that this will be more than enough mitigatoin to keep the valves from floating with 22psi max. boost. So now I need to find some valve shims that are 1.3" max OD , 0.55 min ID x 0.060 thick. Hmm, this Comp CAMs set looks like it will fill the bill: http://store.summitracing.com/partdetail.asp?autofilter=1&part=CCA%2D4753&N=700+115&autoview=sku
I'm designing a tool to remove valve springs w/engine in the car. I hope to get it finished by the time the valve shims get here. Does anyone have the OD of the QV upper valve spring retainers? It's OD is spec'd at 33mm, ID looks to be about 29 or 30 mm. I'm hoping to machine the part of the tool that presses the retainer down & gives you access to the keepers out of a piece of 1" ID steel pipe.
From the MondialQV manual I got these 4V valve spring specs: Free Spring: 38.46mm Closed Valve: 34.00mm Open Valve: 25.30mm Compressed Spring(coil bind):21.45mm Silly me thought I could calculate the valve lift as: Closed Valve - Open Valve = 34.0mm-25.3mm = 8.7mm[0.343"] & this is what I used in my maximum shim thickness calculation. mk e has suggested that I might want to use 3.2 cams to improve flow. This sounded like a good idea until tonight when I realized I'd already taken all the margin out of the spring calculation with 0.343 lift. However, I also remembered the 3.2 cam as having more like 0.350 lift so I decided I'd better go look up the cam specs. From a previous thread, I got these cam lift numbers (BTW, are they buried in the WSMs somewhere?): It appears that the 3.2 cam's 0.348 lift actually exceeds the spring's 0.343 lift spec, so if I tried to use it with a 0.060" shim, I'd end up with 0.055 margin before bind, which is less than the 0.060 that valve spring mfg's specify as the minimum margin. On the other hand, the QV cam's 0.305 lift is 0.040" LESS than the spring's specified lift. In which case, the maximum shim with a QV cam would be 0.100"!!! So I could in fact totally compensate for that 22psi boost and still have margin! Am I correctly relating the cam lift & valve spring specs? Or is the cam's lift spec'd as the lobe height above the cam's back, in which case the actual valve lift is reduced by the valve shim clearance? If this is the case, then the actual valve lift is even less than above. I could use a bit of clarification please. PROJECT STATUS: I got a box from Summit today, was all excited, hoped to finish the tool & start installing the shims & new valve seals this weekend. WRONG: the valve seals were back-ordered, should ship next Friday, so I need to finish up the tool & work on something else this weekend...
Valve lift = cam lift - clearence The actual measured numbers buried in a cam thread, but those cam lift numbers were pretty much verified when WEBCAM spec'd out my stock 3.2 cams.
Russ, I'm sorry, but I'm still uncertain about what the following lift numbers are & don't want to risk making a wrong assumption: are they 'valve lift' or 'cam lift' numbers? The quote is from your post # 1 in this cam thread: Selecting a cam: the soul of the engine http://www.ferrarichat.com/forum/showthread.php?t=158381
No problem! Everytime I spoke of lift in that cam thread, it was cam lift, as defined as the total height of the cam lobe above the base circle. Best of success! EDIT: You probably know this, but Laurie at Webcam did say that Ferrari cams did show tiny variations, even within the same year - not a lot, just a little. Hope this helps. Good luck!
THANKS RUSS! That clarification changes the calculation a bit: shim clearance for both QV & 3.2 is: 0.2mm [0.008"] The important thing is that the max intake valve lifts are: QV Valve Lift: 0.297" = 0.305" QV Cam lift - 0.008" shim clearance 3.2 Valve Lift: 0.340" = 0.348" 328 Cam lift - 0.008" shim clearance The valve spring spec's 8.7mm[0.343"] valve lift is either for the 3.2 engine or for one of the other engines those springs are being used on. It says that I could either increase my shim thickness by 0.046", use 3.2 intake cams, or just have 0.106" bind margin! Anyone want to sell me some 3.2 intake cams cheap?
Because the turbocharger nestles in the V between the heads, it was necessary to create space for it. A quick look at the V with the plenum removed makes it clear that most of the space was being taken up by the coolant plumbing(see pictures below). It's clear that something had to be done to make space. A bit of measuring will reveal that space about 2" high can be gained by just by reducing the height taken up by the cooling piping & hoses, & by relocating the oil cooler. This by itself is over half the space needed for the supercharger! The following pictures provide comparisons of the original head cooling system & the redesigned piping. The pictures below show the OEM system as installed, then a series of views to illustrate just how much vertical space it being taken up: Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
The following pictures of the redesigned system illustrate just how much space has been gained. The first picture is a side view of the new system. It's hard to believe, but mk e was able to squeeze everything down into a single thin layer!! The top view in the 2nd picture, & the 3rd picture of the installed system show how everything now nestles together. Note how mk e converted the large straight lower pipe into a serpentine that snakes between the other pipes. The large upper hose was eliminated by relocating the connections to the head pipes & bringing the hoses directly into the thermostat housing. IMHO, the redesigned system is what Ferrari should have done in the 1st place!!! Also, see how the thermostat housing is just enough off-center toward the forward bank to provide clearance for the supercharger's nose. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
These pictures show the redesigned thermostat housing/WP body. The 1st picture show how all the connections to it line up. The folloing pictures reveal that it is now a piece of modern sculpture! Note that the coolant tank fitting & temp sensor have now been relocated in the front of the housing, just above the waterpump, that way they still are in the combined flow for both heads. I haven't quite figured out how I'm going to make this for production, a custom sand casting is my current thinking: Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Curious of your thoughts of cooling system air evacuation from the heads, is there enough water pump flow to push it down into the plenums so it escapes? Your new thermostat housing looks pretty cool by the way. I didnt see in the pictures where you were locating the oil filter housing, have you decided? Has anyone ever located the oil cooler to the front of the car? I have seen many 911's locate them forward, but not a single 308 I can think of.
What level of boost are you looking for? 22PSI will produce around 150% increase in HP which is well beyond a dangerous level for oem engine components. On a stock engine I would never suggest more than a 33% increase based on MANY years of engine buliding. Anything more than that is asking for trouble. With forced induction, something on the order of 5-6 PSI of boost would be the max I would ever recommend in my engine building days without internal engine mods. Around 80 HP on a 260HP 328, for example, is safe, beyond that...
I also think this might be a good idea. Did the Michellotto cars do this? Anyone with any experience?
I have dual oil coolers in the front of my 308 QV. The oil coolers are mounted underneath the headlights -in front of the wheels. The (2) oil lines run foward on the left side along with the heater hose. ( I do not have a vacuum line running forward - no brake booster). Image Unavailable, Please Login
Progress! Nice! One thing, the hose clamps need to be positioned so that nothing is above the rubber hoses....it's packed that tight. I had to use a small wrench to tighten them. It seems like I did the 2 on the cooling rails first then put on the pump housing and did those 2. I dodn't recall when the center tube when in ...but I think it was last with the rubber hose pre assembeld and clamped to it....it might have been after the hoses on the side rails though. Have a look, it's all about being able to tighten the hose clamps and have them not sticking up on top.
Its probably irrelevant as its been highly modified, but heres a pic I took of a Gt4 race car with one mounted directly behind the radiator. Image Unavailable, Please Login
Now you tell me!!! I was afraid of that! Those hoses are indeed packed tight together! Took me all of an afternoon to get them all on! As you say, it will only go together in one sequence. Otherwise, the hoses that were installed 1st absolutely kept the last hose from going on(sigh). Nothing to be done but to pull things apart again. I've been holding off on pulling the cam covers until I finished making a valve spring compressor tool. I should finish it today & was hoping to get the shims & new valve seals in this weekend. Guess I'll be redoing plumbing instead.
I don't expect problems evacuating the air from the heads. The level of the pipes hasn't changed. While the OEM pipes had risers to the large upper hose, the hose fittings come out inline with the pipe, then rises up to the thermostat. mk e ran that way w/o problems. Oil filter housing is moving back to the luggage compartment bulkhead, probably just beside the coolant tank. With the K-jet gone there's plenty of space back there. I'm sitting on the fence as to oil cooling. I got an oil to water oil cooler from mk e. It goes into the line across the front of the engine that I've been planning on using. However, my car is an early Euro, so it looks like the OEM oil cooler plenum doesn't have to be relocated to get space for the air filter. So I could continue to use it if I can replace the lines with ones that route where I need to run them. Or maybe just run both. Having seen the recent thread about most likely destroying the oil cooler when you remove the fittings, I'm wondering if the fittings are enough like aeroquip so that new lines could be installed with the fittings on the tank? I'd thought of running an up front cooler. The Rx7 got about 30% of it's engine cooling from a large oil cooler mounted down low in front of the radiator. I've got an Rx7 cooler lying around somewhere so it would be a small matter of mounting brackets & running lines to it. However, based on mk e's experience I don't think I'll need it. I can't run dual coolers the way pad did as I'm mounting a pair of intercooler radiators there. Image Unavailable, Please Login
Hey Verell, The RX7 cooler is a good choice because it has a built in bypass thermostat (or at least the ones i used on my old auto x car did. If I recall correctly, however, the inlet and outlet fittings were like 5/8 i.d. - a bit small. The thermostat was sure a good thing, a big help getting it up to temp quickly. Not sure if it has enough surface area though to dump all of that heat you are going to be cranking out. Asside from having to run 3/4 aeroquip through the interior, the big problem was ground clearance. I had it out front under the front bumper and it really worked but it didn't like road contact. The oil to water cooler sounds like a good way to go, if (as you pointed out to me when i was considering one), you have a bigger andor aluminum radiator It looks like it would handle high pressures with no problem. Interesting piece. If it worked for Mike, I'd give it a try. regards, chris
I'm probably going to make the decision as to which way I go until I get much further along. Right now I've got a lot of work to do to get , the intake valve springs & seals installed, adjust cam shim clearances, & the new cam drive system installed. Then I can drop the SC/plenum assembly on. Once that's done, I need to run the intercooler water lines up front & install the intercooler radiators, reservoir, & pump. Then there's installing the Haltech E11V2... I think that with a cooling fan pulling on it's back side, the OEM oil cooler might be up to the job here in NE, at least until I take it out on the track for extended length high power runs. While I'm not planning on using one, those Rx7 coolers had a lot of surface area & even more cooling capacity/frontal area as they had multiple levels of tubes unlike a lot of 'add-on' aftermarket oil coolers. That's why they were so thick. Place to mount one would probably be upper front of the radiator with a baffle plate to direct the air coming thru it above the radiator, thru the area normally sealed with foam, then out thru the bonnet louvers.
Have you considered placing the intercooler radiators behind the rear wheels along with aux electric fans? On my QV, the bottom of the rear quarters have vents. With a little bit of duct work, you could bring fresh air into those areas. I had the owner of an intercooler company go over my car, and that was one of his suggestions. Of course, my rear trunk area is stripped down to bare metal and painted and I already have ducted air into it - my air filter is in the trunk with a 4" duct to the thottle body. (He also designed the actual intercooler to be located in the trunk).
Up front the intercooler radiators will get ram air thru the grille & slots in the spoiler. It's the same area where 328s have the a/c condensor coils. Hmm, this means I need to consider the behind rear wheel location as an option for 328s & other US spec cars. Could you post some pix of your installation? Doesn't work for Euro 3x8s like mine tho, that space behind the rear wheels is part of my luggage compartment on one side, & I'll be replacing the Digiplexes with the Haltech on the other side. Also, I don't want to add additional fans unless absolutely necessary, My 308's alternator is going to see an increased load due to the EGI & intercooler pump as it is. Altho, I'm probably saving enough electricity with my HID headlights to cover the EGI increase, but can't expect others to do the same.
there's actually quite a bit of room below what is the luggage compartment/digiplex comparment . . . there's a metal plate in there (not referring to the metal plate the digiplex's mount on . . there's another one below them) and with a at least a couple inch air gap to the actual fibreglass/outside .. then another inch or two to the grill underneath.
Sean, THERE IS NO GRILLE IN A EURO 308, the digiplexes are down in that well behind the wheel. They are below the luggage compartment floor (& the Euro floor is lower than a US spec car's floor (less insulation))...
