| Author | Message | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 404 Registered: 2-2003 |
Speaking of distributor, here are a couple of shots of the unfinished distributor Ben sent me for test fitting on the car before he finishes. A standard size paperback is shown for comparison. The three holes on the drive dog will fir screw-in dowels where the usual rotor is screwed onto the drive dog in a 3.2. It is really pretty cool in person.    | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 401 Registered: 2-2003 |
Philip Am following his rebuild thread with more than an 'idle' curiosity (yuk yuk - thanks folks, I'll be here all week). Will look at getting a set from Pierce. GT Auto Parts has yet to deliver on the Webers and air box promised weeks ago. Hopefully will be here soon as that is the LIMFAC. Have taken the down time to clean up the engine bay. What's worse is my idle hands are thinking about replacing the Jurrasic Bridgestone RE-71s with Yoko ES-100s (215/50 and 245/45 17) or Pilot Sport A/S (225/50 and 245/45 17). Got the single distributor body from Ben Millermon this week for test fitting as he has never done a 3.2 before, but has done many 308s. Looks very well made with a lot of detail work. Goal is to have have adjustable mechanical advance, less outrageously expensive, more available parts and more reliability; also planning an MSD coil and box. Will post a picture this weekend. Between the carbs and distributor, I have to laugh as I go 'Back to the Future'.... Steady progress, more later | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 387 Registered: 7-2002 |
Russ One other thought. I don't recall which carbs you are fitting and whether you are going for the 40 DCNFs, but Jeff McCormick recommended the Euro idle screws as they provide a far finer adjustment. They have a gently tapered thread rather than a short taper and a "shoulder" - see Greg Rodgers thread on carb rebuilding - he as a pic of the US screw. Pierce stocks them. | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 377 Registered: 7-2002 |
Russ I just got off the phone with Pierce. Here's what I understand after talking to them. First, the LM specs are not likely to be instructive. At the end of the day, the cars are set up not to expire from running 24 hours flat out. Mike at Pierce commented that a GT40 was running at Leguna Seca with LM jetting. It was not able to pull away from 289s. Running way fat. Rejetting, he estimated, probably added 50 bhp. His advice, put in the 36mm venturis, run it with my current jetting. It may need larger pump jets (current is 0.45) and a notch bigger idle jet (say 62 or 63). He also reiterated it needs dyno time to get it right (EGTs, CO levels etc). I'll take me a couple of weeks to get them in. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 388 Registered: 2-2003 |
that makes good sense as the air velocity would be higher. I am still in a quandry about the previous statement on a larger venturi may require a smaller accel pump. Are you going to a .45? I am really watching your idle/accel/float/transition progress and changes closely. | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 376 Registered: 7-2002 |
Russ I exchanged messages with Bill Pound about the venturi sizes. He thought the GT4 LM car was equiped with 36mm solely for performance on the (old) Mulsanne straight and that 34 venturis would produce better lap times due to better mid range response. Will let you know when I get some recs. Philip | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 386 Registered: 2-2003 |
As a point of comparison to Weber replacement conversions to Porsche 911s with Kjet CIS, here are the specs from the 'Porsche 911 Performance Handbook': Weber 40 IDAs, 2 valve engine 2.7 liter (450 cc cylinder) - 34mm venturi, 135main, 145 a/c, F3 3.0 (500 cc cylinder) - 34 mm venturi 160 main, 175 a/c, idle .6 - .65, F3 They again comment on how much fun the engine becomes due to the Weber responsiveness over the Kjet, and say it is the most (and easiest) bang for the buck. Of course, they have the superb pre-done PMO kits. Wish they made them for us. The 911 guys really do well discussing cam and jetting changes in that book (sold at B&N) and explain the mildness of the Kjet cars as everyone was mostly concerned with meeting emmissions rather than performance goals. | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 371 Registered: 7-2002 |
Paul Depending on where you come out on the carbs, you might call Jeff McCormick. He has a set of 48s from a Lamborghini race boat and put them on his 308. He claimed it sounded like a NASCAR racing car coming out of the pits until it hit about 4 or 5 grand and then whoo hoo, off she went so fast he was scrambling to make the shifts. I'd guess with 48s you'd be so over carburetted it wouldn't be any fun on the street, but on the track... Philip | ||
| Paul Sloan (Sloan83qv)
Member Username: Sloan83qv Post Number: 626 Registered: 3-2001 |
Hey Russ, I have now taken my heads (1 that was done but screwed up and a replacement for the 1 that was destroyed by 1st machine shop) to Xtreme Cylinder Heads in Palm City FL, they were recomended by Ferrea Racing. When I dropped heads off last week they had a set of Ferrari GTO heads that they were major league reworking or should I say fabricating as there was some serious damage. I hope to begin the reassemble part beginning in October (Bottom end is done)and be on the road in December. By the way I am thinking about droping down to 44's or 42's instead of the 48's (Newman made do some research and thinking)which should keep it streetable and still fun with the 11:1 pistons and the radical cams along with the ferrea valve setup. I can't beleive that it's over a year but live and learn, glad to see you are closing in on the finish line....LOOKS GREAT! Hey here are my valve covers just waiting for an engine. Paul   | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 370 Registered: 7-2002 |
Russ I need to talk to Pierce and some other sources for jetting recs with the larger 36mm venturis and I expect to get it all ordered this week. I have an event at Gingerman next month followed by a couple of days at Road America and I'll want it dialed in for that. I'll update you with experience as soon as available. On cam timing, you may recall I had the intake cams set to close at 58 ABDC (per the Le mans car) and to keep the bottom end up. Anyway, I was looking through a copy of Bluemel's V12 book which has the cam timing for the early V12s. The 4 cam 275 GTB had intake cams closing at 59 degrees ABDC if I remember correctly along with 290 duration intake and 281 duration (i.e., close to P6) specs. One of the earlier cars was 63 or 65 ABDC -- despite a (static) CR in the 8.8 to 9.2 range. Interestingly (and unsurprizing) to see how peak torque (rpm) moved around. I think the 275 4 cam developed peak torque at 6050 rpm and peak power at 8K. One reference. One of the local shops is re-building a 308. Had a carb car, fitted (inadvertently) FI cams. Ran like a pig. I know the lift and profile of the carb cams are different (and the earlier (75 - 77) cams were more aggressive than the later (78, 79) ones - my (77) intake was 260 degree, ex. 254 degree duration) from the FI cams (which I think were more like 244 degrees duration), but my sense is there would be a lot of opportunity with the 4 valve cars from a "hotter" cam and carbs et al too match. Net, net Russ, I think you'll be in for a fun ride. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 376 Registered: 2-2003 |
Newman Have some basic sorting to do, but yes for different reasons. To best jet the carbs, will need to have some dyno time to futz with the engine under load after we get it close with the gas analyzer in the shop. My main tuning instrument will be my behind as the responsiveness and drivability are priorities. What I'm anxious to see is the maturation of Philip's P-6 cammed 2v with the 36mm chokes and Paul Sloan's monster 308 qv with cams and (gulp!)Weber 48 IDAs! Paul has had some delays (see archives for pictures and details) but expects to get it going this Fall. I will be doing cams later, and have alredy spoken with Elgin and Webcam. More pictures later this week. Watch this space. | ||
| Newman (Newman)
Intermediate Member Username: Newman Post Number: 1260 Registered: 12-2001 |
Russ, do you plan on a dyno run? I really want to know the outcome, you got the gears turning in my head. | ||
| Mark Eberhardt (Me_k)
Member Username: Me_k Post Number: 651 Registered: 5-2002 |
I'd believe the 30-40 hp increase. When I put mine on the dyno with the blower, which included removing the stock injection, it had 50 more hp than I thought it should. The hp increase with boost is a pretty simple calculation, but the only way I could make the numbers work out was to assume the base hp was 270, not 235. I assumed it was the removal of the stock injection, it surprised me it was that much though. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 373 Registered: 2-2003 |
Newman, Frank Capo (Modena Engineering) who has done this in Austrailia says that just opening up the air restriction and flow of the K-ket will be 30 - 40 hp increase with better response. Tech update - have new facet fuel pump and regulator and filter. No more high pressure pump, filter and accumulator. As was noted before, it's amazing how every change is shedding weight from the FI system. Right now it looks like about a total of 60+ lbs or so.... The engine bay certainly has a lot less hoses, valves and assorted paraphenalia. The exhaust air injection valves which can spit back, will be connected to each other. Since I am using a stock carb air box, the crankcase recirc/recovery will be as on the carb cars. We have talked about the vacuum take off, and Gary wants to build a small collection tube from several cylinders rather than my original tap off the side of the manifold like the carb car parts manual shows. Any advice welcome. Will also need a line going to the a/c control vacuum resevoir, which has it's own one way valve. I know the details are not as exciting, but if anyone else wants to do this, just wanted to document the nuts and bolts to pave the way. Hope to have carbs installed this week, then will attack linkage. | ||
| Newman (Newman)
Intermediate Member Username: Newman Post Number: 1251 Registered: 12-2001 |
Im really interested in the 3.2 dyno numbers. Im debating whether or not I should plop in a 328 engine into my 308 with carbs. If the euro 328 is 270HP maybe 300 isnt unreasonable with the carbs. Perhaps a tad more with cams and compression down the road? | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 372 Registered: 2-2003 |
Although not as technically interesting as the carb stuff, thought I would show the powder coated crinkle Cam covers got back today, still with the masking film. The photo shows them a bit brighter than the deep red they are in person.  | ||
| Dr. Mike Adams (Drmike)
New member Username: Drmike Post Number: 26 Registered: 5-2002 |
I dont have the specs handy. But if this is the custom 3.2 app there isn't one yet.  Measure all of the float levels. If they are all equal, raise them all by 2mm at a time until the lean spot is filed. If they are NOT equal, equalize them all the the lowest level, and use the same 2mm procedure. A properly adjusted Weber carb will work smoothly with the accelerator pump disconected. As long as the throttle is applied smoothly. You should be able to pull away from a dead stop pressing the gas pedal very slowly without any hesitation or surging. Once you have that covered, you can play with the pump shot to deal with rapid throttle movement. If someone wants to try my secret self-dyno trick on a V8, it might help. It works ok on V-12s but I'm not sure if 8 cylinders are enough resistance for it to work. 1. Get the engine to idle at a relatively sow speed. 800RPM or so. ( slower the better ) 2. Disconnect 1 carb from the linkage. 3. You are now using the remaining 6 cylinders as a break and you have a poor-man's dyno. Using the one disconnected carb, and a colortune, watch the mixture all the way through the throttle position/RPM range. This way you only need 2 of each jet size to experiment instead of 8 ( or 12 ) and only need to do 1 float level adjustment. You can actually see the rich/lean spots and adjust the jets and float levels as needed. Once you get the fuel curve you want, copy the settings to te other 3 ( 5 ) carbs. Because the 2 cylinders need to turn the whole engine, they run under a full ( or close to it ) load. Not that I think anyone HERE would try this, but.... DO NOT, UNDER ANY CIRCUMSTANCES, FOLLOW THE COLORTUNE INSTRUCTIONS AND USE THE CAR'S REAR BREAKS AS A DYNO BREAK WITH THE TRANS IN GEAR. BAD BAD INSTRUCTIONS ! | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 363 Registered: 7-2002 |
Russ Or is it with bigger venturis, the air moves more slowly at lower rpms and therefore you'd want smaller pump jets? | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 362 Registered: 7-2002 |
Russ My accel jets are stock. Le Mans car had 045 pump jet. Stock and Le Mans car floats were set to 48 mm. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 361 Registered: 2-2003 |
OBTW Thanks Drmike. What float level is stock vs what is the GT spec? rt | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 360 Registered: 2-2003 |
Philip, others Wonder if the throttle dump hesitation at 2000 is an accel pump problem where it takes a moment for the mains to catch up to a lean situation caused by insufficient mixture once the butterflies open quickly without enough accel jet compensation? Did you go to the larger .6 accel jets or keep stock? With the larger venturis the cylinder would see more air when the throttles went immediately open. This is why I empirically went with a .6 accel with a 34mm venturi on the 3.2qv, and based on other stock 308s using it without flooding. I had read by 2000+ rpm you should pretty much be on main circuit by then, and the transitions would play less of a role. best rt | ||
| Dr. Mike Adams (Drmike)
New member Username: Drmike Post Number: 25 Registered: 5-2002 |
A flat spot right around 1500-1800 is usually caused by a low float evel. The float level controls the handoff fom the idle to the main circuit. Try raising all float levels 2-3mm. You can fine-tune this with a colortune. | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 361 Registered: 7-2002 |
Russ A few thoughts on the driving experience with the cams. First, as expected, it runs stronger than stock all the way through redline and beyond. I tend to use 8000 rpm as a limit and it would easily pull beyond this. Unlike the stock cams (260i/254e in my 77), it doesn't run out of oomph at redline or earlier. As I mentioned in my earlier post, I experienced no valve bounce either. Second, bottom end. It feels no weaker than stock. Flooring the car at 2000 rpm in 5th results in some "chugging" and hesitation. Rolling on the throttle alleviates this. Test is a bit pointless as I don't tend to drive mine at that rpm range anyway. Part of the reason for the stronger lower end than expected is the timing of the intake closing (we used 58 at 0.5mm/20 thou checking clearance) and the use of the street operating clearances (a bit wider than the LeMans settings). Idle is smooth but we set to 100 rpm or so higher than stock to help. Fuel consumption. Higher than stock, as expected. At Gingerman I was seeing about 7 mpg. On the road trip out, it was very heavy stop and go traffic most of the way, and my guess is I was seeing 10 or 11. I'd guess 10% worse than stock. Noise. It is definitely louder than stock through the Tubi tail pipes and has a deeper note to it. Fabulous wail at the track and the larger venturis really bring out the induction roar -- it is quite a cacaphony now. Plenty of flames on the downshifts out the back (as before). Despite my concerns (and those expressed of others) on drivability on the street in heavy traffic, it is really not bad. Careful moderation of the throttle below 3000 helps a smooth driving experience. Performance. One test we did was to drive a QV back to back with my car. My car is noticably quicker up to say 6500 or 7000 in 4th (about what I recall at Gingerman) and when I had the opportunity to "air it out a bit" on the return trip, it seems to pull more quickly in 5th for as long as I felt comfortable holding on to it. As I mentioned, next I am going to try some 36mm venturis along with some larger jets which I hope to have done for events at Road America and Gingerman next month. I'll keep you posted. Separately, Russ/Andy/Others, do you know where the specs for the progression holes are posted for the 40 DCNF 4X series carbs? Will post details of the 36mm etc upgrade when available. Russ, feel free to email me specific questions. You have my details. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 358 Registered: 2-2003 |
Philip Congrats on the great day with the P-6 cams. Look forward to hearing the details of an actual operating 308 with the hi-po cams! best rt | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 359 Registered: 7-2002 |
Russ Just got back from Gingerman. Bone tired so this is going to be short. Car ran fabulously. Much stronger than a QV we drove and just keeps pulling at the top. No valve bounce. Bottom end is almost as good as stock, there's a little bit of stutter below 3000 but it's quite drivable and it idles very smoothly. Going to try 36 mm venturis (like the LeMans car) and bigger jets. Will keep you posted. Andy Good thought on the progression holes. I'll look up stock and LeMans and post in a day or so. | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 356 Registered: 2-2003 |
Andy Thanks for the great email. EGT is a great idea. Will definitely use it for setting - can't lean on the fly to best temp, so may not add an installed gauge. Will be starting with the stock Kjet cams (which have minimal back pulses as not to confuse the plate air mass sensor) so may not be as likely as P-6s to experience the hesitation. Will let you know here in about 2 weeks or whenever GT Autoparts wakes up and sends the carbs. When adding cams later, will really look at the pulsing as you say. Based on the archive, I did a chart of many 308 carb setups FChatters said they were using, and found the largest that worked for folks was the .6. Since the 3.2 qv will be flowing a bit more air than them, that was my starting point. This was also corroborated by the 246 (same 400cc cylinder capacity as my 3.2) high flow racing setup which was .6 . Since the Mondial engine is a 4v (i.e. high flow), I think this is a good start. Any advice on accel pump jets is welcome as well. Using the same chart, I am starting with a .6 as baseline. Thanks again for the transition hole advice. and please post the #s if the Alzheimer's clears! best rt | ||
| Andrew A. Illes (Andyilles)
Junior Member Username: Andyilles Post Number: 185 Registered: 10-2002 |
Russ & Phil... Yeah, a hesitation around 1,500-2,000 is fairly common... partly because of the P6s overlap and resulting dynamic pulses (standoff). As I wrote in the high-comp string, drilling the progression holes is really a better solution than going up, up and up on the idle jets... or the pump jets either, for that matter. The problem isn't at idle, or when you punch it... it's at transition, so you just need more fuel as the butterlies are opening, and doing the holes is what takes care of that phase. That said, 50 pump jets work well. I didn't know the Lemans cars had that progression hole tweak (thought it was my discovery... DUH!!!) but it works. Important thing is to try one hole at a time, with VERY small increments. The top holes are the least sensitive, so they're the best ones to start with. It doesn't take much. Wish I could remember the drill sizes I used, but can't.. sorry. Alzheimers, ya know. Russ... if you're going to add instrumentation, may I suggest EGT's instead? Ask any pilot. Really glad you guys are both about ready to smoke some serious rubber... Makes the 'ol F heart go vroom, vroom, vroom. Best regards, Andy | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 357 Registered: 7-2002 |
Russ Good questions. My guess is progression holes are the issue and I know the stock holes were modified for the Le Mans car. Have both specs, will look at it with the tech @ Gingerman this weekend. I did bump the idle jets to 60 from 55. Gary Kral (service manager) and the only guy to have driven it yet says it is idling as well as a stocker. I'll let you know about sound and any drivability stuff next week. Also, we'll do a plug cut or two and may play with the jetting at the track. If so, I'll let you know any changes and the results for the tests. I did not change the pump jets from stock. On the timing spec at 20 thou/0.5mm (checking clearance), the intake cam is timed at 50/58 (versus factory of 54/62 - the earlier closing of the intake valve following Le Mans spec and Dema Elgin's advice to help the low end) and the exhaust cam was timed at 64/44. We set running clearances to stock after a discussion with Bill Pound (the LM car had tighter clearances but we felt the stock clearances would help cool the exhaust valve a bit more through longer seat time and keep torque up a bit more). Fuel pump is stock (carb car). Headers are stock although Dema Elgin's view was the car probably needs a different header/exhaust from the Ex Valve timing and lift. I am running a Tubi. Hope this helps, Philip | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 354 Registered: 2-2003 |
Phillip Woo-Hoo! Very exciting - sounds terrific. From what I have read the 1800 rpm hesitation is a transition thing between idle and main systems. May want to go up in your idle jet or rework the transition holes. Saw some info over this in a previous thread. How much overlap did you end up with? With all the previous discussion on intake/exhaust pulses and the stock header lengths, would like to see how the real world pans out. Also - what did you use for an accell pump? I am going larger with a .6 and would like to hear what you used and how it responds to large throttle movements. This is all fairly applicable to me since I am also using 34 mm chokes with higher flows, but due to more valve curtain area and slightly more displacement. Curious - Did the carb or exhaust sound change at all? Anyway, I'm pretty proud for your success and await further news. Mine should hopefully be running end of next week. best rt | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 354 Registered: 7-2002 |
Russ Here's what I've done for initial jetting on my 308/P6: 145/60/F36/180. 34mm venturis. Floats at 48mm. Intake cam timed to close at 58 ABDC. I haven't driven it yet. Gary, service manager at Continental says that there's a slight hesitation at 1800 rpm, which we need to sort out, and then it just pulls and pulls and pulls. He's quite surprized at how the bottom end has held up and the relative improvement throughout the range. I'll have it at Gingerman this weekend and, depending on scheduling, hope to have it on the dyno soon. Keep you posted. | ||
| Philip Airey (Pma1010)
Member Username: Pma1010 Post Number: 346 Registered: 7-2002 |
Russ Good to see it coming along - I am sure you are too! One point on your thread, the O2 feedback. To be useful as a tuning aid you'll really need a wideband. BTDT - the usual Bosch et al O2 sensors are only useful over a narrow range and actually produced contra indications at times versus a wideband. Cams are finally in my car and re-jetting is occuring as I write. We're setting it up pretty fat (145/60/F36/185 with 34mm venturis) to start and for my event at Gingerman this weekend. We will then refine on dyno, I'll let you know results and where the jetting comes out. Keep us posted. | ||
| dave handa (Davehanda)
Intermediate Member Username: Davehanda Post Number: 1515 Registered: 5-2001 |
VERY cool. Keep us posted on the tuning aspects and dyno results. AND please post a sound clip! :-) | ||
| Mark Eberhardt (Me_k)
Member Username: Me_k Post Number: 643 Registered: 5-2002 |
Cool | ||
| Russ Turner (Snj5)
Member Username: Snj5 Post Number: 345 Registered: 2-2003 |
Hello to all. Just got back from checking up on the 40 DCNF conversion to the Mondial 3.2 at Grand Touring. Biggest first impression is: Wow! - look at all that room now the K-jetronic is removed, and not to mention about a 50 to 60 pound weight loss if you weigh all the hardware and peripherals removed. Have finished the cam belt replacement. Decided to wait on more aggressive cams for the time being as want to sort the carbs/ignition first. The manifolds (a NOS Modena Engineering/Frank Capo part) have been ported/polished to match the 3.2 heads. We are currently waiting for the re-jetted carbs, trumpets and 308 Euro airbox from Bill at GT airparts. Based on previous FC thread, will go with a facet or bendix pump. Issues being addressed currently are: Brake booster vacuum line take off Vacuum line take off for A/C control Linkage - a frayed cable was found so will have to be replaced - yuk. bypassing fuel pump relay Will initially be checking mixture settings with exhaust gas analysis. See previous thread on 308 hi-comp for carb settings. May wire up one of those little mixture doofers to the existing O2 sensor to watch while I drive. Have a Stebro 'euro resonator' glass pak to replace the cat, and already have an existing tubi. Whle they all are very confident the carbs will improve the engine, what the mech (Gary) and others seem quite excited about is what it will sound like with the Webers, 4V and tubi. So now we wait for the carbs as the cam covers are being powder coated crinkle matt dark red. Once the carbs are sorted, have a Millermon single distributor coming to best tweak the advance as well as make the ignition more reliable and easier/ cheaper to maintain. And, no vacuum advance line needed. Anyway, as always, any advice appreciated. And I really need to say that everyone at Grand Touring, especially Gary and Kendall, have been terrific to work with. More in a week or two. best to all Russ OBTW - have a 'working well when removed' 3.2 l Bosch K-jet system for sale.   |