hi everybody.
thanks so much to grumpy for the great site. incredible resource, i appreciate every little thing you do here!
i am coming back around to my first SBC EFI project in over 15 years.
more on my current experiment in a new thread elsewhere at grumpy's.
just for giggles, here is part II of the 87 formula story i posted on the other thread.
after 3 years of daily driving/weekend bracket racing, coinciding with my new construction company 'taking off ' in terms of profit, i planned a buildup of my custom ordered, stripper 87 TPI/5spd formula firebird mentioned in the other thread.
picking up story, late 1991:
i pulled the Formula into my construction warehouse ( nice 1500 sq foot garage with high ceiling), tore it down to bare body/frame.
little did i know that it would be 18 months til the completion of the job.
i had access to a 4 bolt main block out of a 4X4 chevy pickup CIRCA 1974. i laid in a muddy field unbolting that engine from the hulk.
took it down to our local 'racer' engine shop. ( AMS in albuquerque, locals know doug and his great builds), i had them balance, blueprint and otherwise skillfully build the best 355(.030 over) bottom end possible, using the parts i brought them. the cast crank was lovingly deburred by yours truly before the motor build began.
i researched as many TPI articles as i could find in hot rod & car craft. ( other chevy, hot rod mags had not caught on to the EFI trend by '92). john lingenfelter had a breakthrough article in hot rod, late 80s/early 90s. he had taken the TPI setup to new extremes by porting, etc and was the first to get the hot rod magazine writers to get excited about TPI. by crossbreeding a 4 inch Porsche Mass Air Sensor ( vs the GM/bosch +-3.5")he had gotten a corvette running really respectable qtr. mile times while getting incredible day to day driveability.
SLP engineering was up and running at this point, but i was unimpressed with their customer service after my friend Dave Pike had received poor followup on a mfgr's faulty setup of their after market 3rd gen posi rearend.
i decided to use ( new at the time) Accel runners instead of the available TPIS larger runners or SLP tubing runners because the accel's were affordable at SUMMIT and were cast aluminum, instead of tubing. this allowed me to 1/2 siamese the runners, instead of the full siamese of Arizona speed and Marine's 'siamesed' runners ( large diameter tubing runners siamesed with sheetmetal), by going only halfway down the runner area by connecting the ports. my previous porting experience came in handy.
i used graph paper to chart out the torque/hp curves of all the published info ( scarce at that time) in modded TPI based setups. this got me the nickname of "mr' Charts and Graphs" with my racing buds, who normally only had their cars disassembled for no more than a month at time.
using the research, i decided that the torque curve of the stock TPI combined with the high RPM breathing of the prototype superram lingenfelter setup was the best of both worlds. i chose a cheapy summit brand cam ( made by crane hahA ) similar to lingenfleter's grind and brodix street alum. heads from summit. they had good flowing ports and only needed slight milling to achieve my important 10.5:1 compression ratio.
i carefully studied the cam indexing articles i could find, bought a degreeing wheel and indexed the cam perfectly to mfgr's specs using summit's adjustable timing gear set.
i ported the brodix heads nicely, and also gasket matched them carefully to the Mr.Gasket intake gaskets. from there, i ported every bit of the stock GM manifold base, until the aftermarket Edelbrock ports looked small by comparison. the GM plenum was ported, along with smoothing on the stock 52 mm throttle body. later, a simple air divider was added.
to be sure that the porting work was working to max effect, i trial assembled the TPI setup at least 8 times, using specially bent inspection wires and tiny scribe marks on each interface to perfectly gasket match every single component in the TPI intake setup. this was very time consuming, but critical in ensuring that every drop of airflow increase was being utilized. upon final assembly of the TPi setup, each scribe line was micro-aligned to ensure that the port matching was complete.
with the complexity of assembly that accompanies the stock TPI assembly, i don't see how anything less than the above method of assembly would assure maximum airflow results.
due to budget constraints, stock coil, distributor, fuel pump, injectors , t5 trans etc were used. total investment was under 20k including the purchase price of the car in 87.
i rebuilt the stock style water pump using summit's inexpensive 'low drag' impeller kit. summit had an inexpensive windage tray, so i adapted it.
the rear diff was rebuilt using aftermarket GM perf. parts australian BW 3.70 gear set. ( $ 270 or so at the time), since my factory rearend was the Aussie borgwarner.
i made my own custom floorboard-fitting driveshaft loop since i knew i would be running slicks and needed to meet NHRA req's for slicks.
i installed extended studs on my rear axles.
also required for slicks was a scattershield bellhousing. these were cheap from summit, but needed extensive modding to fit a 3rd gen Fbird at the time.
the car, after a year and half, roared to life in the warehouse. in the meantime, i had managed to cut 250 pounds of dead weight out of the car - bumper beams, emissions crap and other bracketry/sound deadening, etc.
the car now weighed 3070 ( vs the actual stock weight of 3320), and was ready for testing of the new, mighty, heavily modded 355.
keep in mind, that in 1992, the people who were modding stock-based EFI systems were a new and rare breed, made up of mostly Buick GN guys, 5.0 mustang dudes and a very few Fbody freaks like myself and Dave Pike.
the computer solution, along with the initial track times of the shakedown runs will be posted in PT.3....
thanks so much to grumpy for the great site. incredible resource, i appreciate every little thing you do here!
i am coming back around to my first SBC EFI project in over 15 years.
more on my current experiment in a new thread elsewhere at grumpy's.
just for giggles, here is part II of the 87 formula story i posted on the other thread.
after 3 years of daily driving/weekend bracket racing, coinciding with my new construction company 'taking off ' in terms of profit, i planned a buildup of my custom ordered, stripper 87 TPI/5spd formula firebird mentioned in the other thread.
picking up story, late 1991:
i pulled the Formula into my construction warehouse ( nice 1500 sq foot garage with high ceiling), tore it down to bare body/frame.
little did i know that it would be 18 months til the completion of the job.
i had access to a 4 bolt main block out of a 4X4 chevy pickup CIRCA 1974. i laid in a muddy field unbolting that engine from the hulk.
took it down to our local 'racer' engine shop. ( AMS in albuquerque, locals know doug and his great builds), i had them balance, blueprint and otherwise skillfully build the best 355(.030 over) bottom end possible, using the parts i brought them. the cast crank was lovingly deburred by yours truly before the motor build began.
i researched as many TPI articles as i could find in hot rod & car craft. ( other chevy, hot rod mags had not caught on to the EFI trend by '92). john lingenfelter had a breakthrough article in hot rod, late 80s/early 90s. he had taken the TPI setup to new extremes by porting, etc and was the first to get the hot rod magazine writers to get excited about TPI. by crossbreeding a 4 inch Porsche Mass Air Sensor ( vs the GM/bosch +-3.5")he had gotten a corvette running really respectable qtr. mile times while getting incredible day to day driveability.
SLP engineering was up and running at this point, but i was unimpressed with their customer service after my friend Dave Pike had received poor followup on a mfgr's faulty setup of their after market 3rd gen posi rearend.
i decided to use ( new at the time) Accel runners instead of the available TPIS larger runners or SLP tubing runners because the accel's were affordable at SUMMIT and were cast aluminum, instead of tubing. this allowed me to 1/2 siamese the runners, instead of the full siamese of Arizona speed and Marine's 'siamesed' runners ( large diameter tubing runners siamesed with sheetmetal), by going only halfway down the runner area by connecting the ports. my previous porting experience came in handy.
i used graph paper to chart out the torque/hp curves of all the published info ( scarce at that time) in modded TPI based setups. this got me the nickname of "mr' Charts and Graphs" with my racing buds, who normally only had their cars disassembled for no more than a month at time.
using the research, i decided that the torque curve of the stock TPI combined with the high RPM breathing of the prototype superram lingenfelter setup was the best of both worlds. i chose a cheapy summit brand cam ( made by crane hahA ) similar to lingenfleter's grind and brodix street alum. heads from summit. they had good flowing ports and only needed slight milling to achieve my important 10.5:1 compression ratio.
i carefully studied the cam indexing articles i could find, bought a degreeing wheel and indexed the cam perfectly to mfgr's specs using summit's adjustable timing gear set.
i ported the brodix heads nicely, and also gasket matched them carefully to the Mr.Gasket intake gaskets. from there, i ported every bit of the stock GM manifold base, until the aftermarket Edelbrock ports looked small by comparison. the GM plenum was ported, along with smoothing on the stock 52 mm throttle body. later, a simple air divider was added.
to be sure that the porting work was working to max effect, i trial assembled the TPI setup at least 8 times, using specially bent inspection wires and tiny scribe marks on each interface to perfectly gasket match every single component in the TPI intake setup. this was very time consuming, but critical in ensuring that every drop of airflow increase was being utilized. upon final assembly of the TPi setup, each scribe line was micro-aligned to ensure that the port matching was complete.
with the complexity of assembly that accompanies the stock TPI assembly, i don't see how anything less than the above method of assembly would assure maximum airflow results.
due to budget constraints, stock coil, distributor, fuel pump, injectors , t5 trans etc were used. total investment was under 20k including the purchase price of the car in 87.
i rebuilt the stock style water pump using summit's inexpensive 'low drag' impeller kit. summit had an inexpensive windage tray, so i adapted it.
the rear diff was rebuilt using aftermarket GM perf. parts australian BW 3.70 gear set. ( $ 270 or so at the time), since my factory rearend was the Aussie borgwarner.
i made my own custom floorboard-fitting driveshaft loop since i knew i would be running slicks and needed to meet NHRA req's for slicks.
i installed extended studs on my rear axles.
also required for slicks was a scattershield bellhousing. these were cheap from summit, but needed extensive modding to fit a 3rd gen Fbird at the time.
the car, after a year and half, roared to life in the warehouse. in the meantime, i had managed to cut 250 pounds of dead weight out of the car - bumper beams, emissions crap and other bracketry/sound deadening, etc.
the car now weighed 3070 ( vs the actual stock weight of 3320), and was ready for testing of the new, mighty, heavily modded 355.
keep in mind, that in 1992, the people who were modding stock-based EFI systems were a new and rare breed, made up of mostly Buick GN guys, 5.0 mustang dudes and a very few Fbody freaks like myself and Dave Pike.
the computer solution, along with the initial track times of the shakedown runs will be posted in PT.3....
