hi grumpy,
i told you a little about my project, will post more about the specifics later our intake/ electronics experiment but here is a brief overview.
i bought a 1985 pontiac parisienne about 5 yrs ago as a daily driver.
the paint was ratty so i pulled off the vinyl roof, fixed a few dents and painted it with an ocean wave pattern that was sort of inspired by scallops on 50s hotrods. i used rustoleum from home depot mixed to my own blends of burple and purple, painted the whole thing with a brush. i used to be a sign painter, so i got a pretty good flow on the paint.
i am going to paint the logo 'TAXICAB FROM HELL' on the doors and trunk, along with bigger wheels
the original 305 got tired, so i found a very nice bargain on craigslist.
a guy had a sbc 400 that was built with very high end parts and balanced/blueprinted by a reputable shop over 20 yrs ago, but the 1960 chevy belair prostreet rod he put it in was driven less than 20k miles in the entire time.
he had tried numerous setups on the motor over the years, but the setup that was the fastest was a tunnel ram with 2 fourbarrels.
my son sean has three years of mech engineering school under his belt, he convinced me to go efi for tuneability, mileage, smoothness - all the reasons you all know so well.
i wanted more top end than a tpi setup would give, even modded.
we started trying to think of a way to get the low/ mid torque of a long runner setup combined with a second stage large volume capability, trying to get the best of both worlds similar to a dual runner setup like nissan, honda and others have done.
we envisioned a sort of 'passive' dual runner simulation adding runner length to tune low end torque, then ramming high rpm air into the runners, by placing two small drive by wire throttle bodies directly over the runners( imagine two throttle bodies right on thop of the stealth ram plenum). the runner extensions can be simply machined like tall carb spacers ( bolts betweeen the plenum and base). for regular 700- 4000 rpm operation, the regular 52 mm throttle body will work as normal. then at some point in the rpm band, the secondary throttle bodies kick in , controlled by the mega squirt system programmed by us.
i know many of you will think of the downsides ;
massive height ( not a prob, i want it to stick out of the hood)
a tuning nightmare to dial in the secondary operation, seemingly needless complexity., cost.
the throttle bodies are around $100 each if we use the VW golf type. the computer will be necessary anyway, no extra cost there. the runner extensions will be machined by us, so the only cost there is aluminum. we will have to also machine a plate to accept the TBs on the plenum top, and cut the plenum. can't think of any other cost except incidentals
yes, we could make similar power using the stock stealth ram setup, but this is a theory we are dying to test out. if it works, the driveability around town will be really fun.
think about the on-car back to back chassis dyno tests we could do to verify our numbers:
test a: full operation using all 3 throttle bodies, once we dial in the optimum point ( assuming we find one!), with the runnner extensions in place. should have a strong flat torque curve ( TPI like)
and very strong hp numbers up top.
test b: remove runner extensions, run the triple throttle body setup on the stock stealth ram setup, take some time to dial in the secondary TBs, compare to test A.
test c: turn off the signal to the secondary TBs, run the stealth as stock to see if the high hp numbers change (decrease).
test d: install runner extensions again, use only single TB, see how the mid torque compares to test C.
we are going to calculate proper runner length using software ( forget what sean called it). he and his buds have done this on 4 cylinder motors and tuned their runner lengths , got great results.
anyone have any thoughts on this? need more clarification on what we are trying to do?
will the secondary throttle bodies get sucked open by intake pressure at part throttle, primary TB operation? will there be a bad effect from turbulence with 3 throttle bodies all filling the space at the same time?
will our high rpm breathing capability be limited by the runners- negating the effect of the secondary TBs?
i have studied the mid torque numbers of many setups, was looking at the comparo of super ram to stealth ram, seems the super ram has a torque peak of around 800 rpm lower. i would like to duplicate the effect of the super ram, increasing the stealth ram runners to super ram length, or close.
other info:
not sure what the cam is exactly, unfortunately. previous owner said it was an agressive high Rpm type hyd. comp cams grind. this is supported by the fact the the tunnel ram ran best on this motor. i believe he said lift in the high 4s to low 5s, with long duration, not sure about anything else. changing the cam would be easy, also maybe i will set up a test to measure what is currently in there.
heads are L98 vette heads, previous guy had them ported at some point. i understand this will probably be a weak link given what we are trying to accomplish. better heads down the road would be another great experiment.
injectors will be sufficient, sean has all the needed skills to make sure we are sizing correctly. he also is very experienced at tuning fuel/timing maps.
we will be using some type of equal length long tube headers with an x crossover.
tranny is 700r4 , will be getting a police car type caprice 10 bolt with 3.45 gear, i hope. want to maximize rear tire to 315 width , tubs will be necessary, possibly other susp mods to fit, i want to keep the fender skirts!
