After attending to a few details and rebuilding the muffler I put it on the dyno to re-test today. I run everything on the same Dynojet 248 I've been using at the shop I work for since 2002. Comparatively my old 99 GTS made 295rwhp 233rwtq on this dyno. My 95 Berlinetta when I first got it and did high flow cats, secondary cat delete and capristo 2 was 327rwhp and 245rwtq. Everything done to the car now is- Ported heads, +.5mm Ferrea intake and exhaust valves, multi angle valve job. Milled heads for raised compression. Now 11.5-1 Original 2.7 Motronic ecu's. New CHE valve guides and titanium CHE valve spring retainers. 4-2-1 headers, titanium y-pipe, titanium muffler (I built) Ported- Throttle bodies, inlet bells/plenums and air box inlets. Lightweight flywheel. Revised cam timing. (intake slightly retarded and exhaust slightly advanced) 383rwhp 259rwtq. Current weight is 2800. Image Unavailable, Please Login Image Unavailable, Please Login
Thanks. I did most of the work but with sending the heads out for the guides and valve job, valves, materials for the headers/exhaust and parts for the major service, clutch maybe 20k? I can try to figure it out.
Those are incredible numbers! After seeing what Singer's are bringing and all their hype, was just thinking about this very sort of thing. First, did you consider increasing engine internal size to 3.6 or larger? F360 = 85 x 79 F360 dimensions vs. F355 = 85 x 77 Second, what have you done to drop weight? I'd really wonder how lightweight the F355 could be made with a Singer sort of investment E.g., Titanium or carbon/titanium or aluminum rear subframe [the OEM subframe is really heavy], aluminum suspension arms, carbon ceramic brake discs, carbon fiber door cards (still covered with leather a la Singer), carbon fiber lower halves of the doors (that plastic /composite part is very heavy), titanium exhaust, Lithium battery, etc. Would love to learn more about your work on your F355 and with photos of course Tell us more about your titanium muffler. How does it sound? Any sound issues at certain RPMs? Weight? Even Capristo mufflers are pretty heavy so a custom Titanium muffler would be wonderful!
He should really start a thread documenting what he's done in his pursuit of improving his F355. Call it something like "95 Berlinetta weight reduction and modifications.". That would be swell...... I know that it would be one of my "watched threads".
Some food for thought: That type of engine size change would do zero for power and just reduce the rpm it made peak HP at. That could be useful if you're trying to pass emissions with more aggressive cam timing (or could not reliably rev the engine any higher), but without upgrading cams/airlfow wouldn't make the car any faster and probably a little less fun. The 355 engine probably tops out at 9500rpm valve-train wise so there's still some room left before needing more stroke. Increasing the bore on the other hand usually unshrouds the valves to let more air in, so is almost always worth some power. I don't think there's any room to do that on the 355 without spending a ton on custom liners...The block was pretty much maxxed out with the 355 and 360 and that's why they built a new engine for the 430. Carbon for non structural items like interior parts is a waste, you can use woven fiberglass mat and get the same weight savings at a fraction of the cost. Non structural CF is one of my pet peeves, it's purely for looks as you can do the same with much cheaper materials. Door cards and the like, especially if covered with leather, would not benefit at all from it. Structural, on the other hand....Roof, external doors, fenders, floor pans and other flat sections of the unibody, could all be made from CF to get significant weight savings and likely increase structural rigidity. Rear subframe and suspension in alternate materials really should be done by somebody with requisite engineering degree and FEA software to optimize. Or use off the shelf suspension items from eg a 360 that has already had that done...but the 355 is a sweetheart when it comes to handling and the 360 has different geometry so I'd be loath to do anything that might spoil it. It'd be a lot of work and mucho dinero to do properly.
Carbon for non structural items like interior parts is a waste, you can use woven fiberglass mat and get the same weight savings at a fraction of the cost. Non structural CF is one of my pet peeves, it's purely for looks as you can do the same with much cheaper materials. Door cards and the like, especially if covered with leather, would not benefit at all from it. Structural, on the other hand....Roof, external doors, fenders, floor pans and other flat sections of the unibody, could all be made from CF to get significant weight savings and likely increase structural rigidity. Rear subframe and suspension in alternate materials really should be done by somebody with requisite engineering degree and FEA software to optimize. Or use off the shelf suspension items from eg a 360 that has already had that done...but the 355 is a sweetheart when it comes to handling and the 360 has different geometry so I'd be loath to do anything that might spoil it. It'd be a lot of work and mucho dinero to do properly. I agree to a degree. CF is lightweight and would reduce weight as door panels as OEM are very heavy even without the leather covering. My Fiorano carbon fiber center console definitely weighs less than the regular part. As for that rear subframe, its a perfect place to start. Have you ever tried to lift one of those things even stripped of all components? Thye are heavy. Need to get one weighed. As for suspension, I'd replicate the OEM arms but in aluminum or titanium so as to keep oem geometry. I don't believe 2mm more stroke will really impact RPMs especially as you say it can rev to 9500 now and max power is below 8500. The weakness of the 355 motor is its lack of torque. Torque of 355 is just 268 lbs/ft. By comparison, 458 makes nearly 400 lbs/ft. I drove a 308 with a 360 crank and it revved like mad.
Congrats for a hard job paying off. Can you give more details on the lightweight flywheel? Did you have the front pulley modified with a damper?
In retrospect, or looking forward with your experience, what else could be done to improve power while maintaining reliability and also maintaining sufficient low down torque and flexibility? Did you look into cams that would make max power at 9k rpm? Also, how heavy was factory flywheel and how much does your current flywheel weigh? Other than making the motor rev up faster, were there any other objectives of the lightened flyweel? Sorry, very impressed by your works so so many questions )
Thanks everyone. The original clutch/flywheel- 25.2lbs lightweight flywheel, rebuilt clutch with sprung hub- 17.4lbs Just chasing overall weight reduction and thought this was a good place to do it. The flywheel is from Hill Engineering and they said they wouldn't recommend it for the street but it drives perfect on my car. It may not if it was 400lbs heavier and back to it's original weight. The crank pulley is original. As for engine displacement I agree with Pete on everything and he explained it perfectly. That being said, as for increasing torque, sure more displacement but shifting the power curve to the left isn't something I would want to do. I don't lug the car or drive it at low rpm and big throttle input. So if I'm driving it normally I don't need more low end torque and if I'm driving it quickly it's going to be at high rpm so that's where I focus on increasing power. If you objective is to increase low/mid range torque more displacement would help but as Pete said, you are shifting the power curve to the left and that's the opposite of what I want. I did consider building an alloy rear subframe but after more thought I think chromoly would be the best. Should be able to just copy it in chromoly in a lighter gauge and it would still look original other than tig welds. Power increases from here would be changing the exhaust again but deviating from the factory layout. So more of a race exhaust but I really like the current setup and the bypass valve functionality. Slightly larger throttle bodies and shorter/straighter velocity stacks may help along with more plenum volume. At that point remove the dual maf's and go with newer engine management. I might build a subframe at some point. (would definitely if I had a spare one to fixture). I don't think, at least for a while I will do anything else with the engine. It drives perfect and feels amazing so not much motivation to take it back apart at this point.
New engine management would simplify long-term ownership by eliminating some of the quirks in the OBD systems. Plus it would look great and could result in more positive intake noise. I'd be extremely interested in a significantly lighter suitably strong rear subframe. Where are you located? Maybe collective we can find you subframe and send it to you.
Thanks! I forgot to address cams. Here is a dyno sheet from Cat Cams. Picks up significantly above 7000rpm but much softer below 5200 or so. May be a good option for a race car but maybe not so much on the street. I could possibly have something smaller custom made that was still an improvement over stock but not sure I would do so without raising the compression even more. Image Unavailable, Please Login
TTV apparently make a single mass flywheel for the F355 designed to work with the clutch (I assume PP + spring centered disc) of the 360. Despite the 360 also making without a crank damper I am curious if it is acceptable to lose on the F355 the dampening effect of the DMF considering its location way far back and the resulting way higher kinetic inertia. This is a different vibration model than the 360.
I used the original/machined pressure plate of the F355 and had a new clutch disc made with a sprung hub. I paired the Hill single mass flywheel with their upgraded quill shaft with "much more torsional flexibility". https://www.hillengineering.co.uk/162909
Fantastic!! Now we know for certain the earliest 355 engines have the lightest pistons and rods . Your last dyno was 373 rwhp. You gained 10 rwhp this time around. Was that from the intake modifications + ITG filters?
Hi Ken. I removed the carbon intake tubes as I felt they didn't allow for enough relative movement and ordered new oem intake bellows. I never did order the ITG filters but think they could help. I think it was mostly from increasing the tailpipe diameter (and muffler internal diameter to match)
