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Intake large enough? 58mmTB - 1200 cfm (4-27-19 dyno results)
I been working on this car and its ready to hit the road in the next few weeks, dyno day on the 27th of April. Previous owner had lingenfelter intake elbow with 58mm TB on it and a stock rubber intake hose with why I dont know a 3"-2.5" pipe inside of it. Im sure it was choking it because he said at wot it still had a little intake vacuum on the dyno pulls. It made 440rwhp and 450 rwtq. Since acquiring the car I put on speedmaster 1200 cfm TB, extreme velocity intake hat 3.5" opening with 3.5" intake rubber tube to the ram air box. It still has a sucking noise at idle but im hoping thats just this large 436 SBC inhaling profusely. I had a trailblazer ss that had a 4 inch intake but that was still larger than the stock throttle body yet that thing ran like an untamed animal 12.27@112 with just bolt ons. Am I leaving hp and tq on the table?! I'm hoping(460hp 465tq) it picked up a few hp as its running much better now that I fixed the injector timing(new 48# injectors also) in accel dfi tune, and the previous over had one of the fuel tables totally backwards and it would tip in terrible and stumble. If it dont put out the numbers ill take the hat off and run the TB wide open lol just like I used to do with 383 carb setup in my previous 88 GTA. Any one with a single plane efi with big cube SBC have any thoughts on this or some pics would help also.
Only one way to find out but do some pulls and check vacuum at wot. If if air fuel changed
ram air effect can overcome some lack of area. On a dyno run you dont have ram air effect so it may pick up on the dyno but not as much while actually running at speed down the track
but imo it needs all the air flow it can get so bigger is only going to be helpful. It wont hurt
i always hit me head on something lol, yes i run at atco, hope to get there soon. If this pig dont run low 11's itll be for sale or part out by the end of summer
I may run into you up there at some point (I'm in Central Jersey). I agree with Justin though, if you have access to datalogging, do a quick pull as is and check your kPa, then remove the intake w/bonnet and see if your kPa changed by doing another quick pull, and check to see if your air/fuel has leaned out throughout. Engine sounds very healthy...
I will log on the street, dyno, and track with the DFI once I get plates and insurance. Gotta get bill of sale from previous owner but hes out traveling the country snow boarding lol. Its quiet cause it goes thru 2 mufflers, first a 4" bullet and then a walker 3". Thank god theres a 4" electric cut out after the 4" bullet, cause with the cutout closed im sure its choked on the exhaust side too.
I will log on the street, dyno, and track with the DFI once I get plates and insurance. Gotta get bill of sale from previous owner but hes out traveling the country snow boarding lol. Its quiet cause it goes thru 2 mufflers, first a 4" bullet and then a walker 3". Thank god theres a 4" electric cut out after the 4" bullet, cause with the cutout closed im sure its choked on the exhaust side too.
I remember those Accel DFI systems, very user friendly and easy to navigate. I just uploaded an exhaust video on my thread, but my phone's audio picks up some funky noises when it wants to. I like the way your exhaust sounds. The tip in is what is bothering me on mine (running a 48mm throttle body), which is why I am considering a 58mm throttle body myself at this point. I think you just sold me on it, seriously....
58mm tb is great and you can find them for cheaper nowadays. I couldnt pass up this speedmaster 1200 cfm TB it was under 300 with new thottle cable iac and tps, I had the extreme velocity hat laying around from my last thirdgen too.
58mm tb is great and you can find them for cheaper nowadays.
I've got an AWESOME deal on a Holley 58.....early style....if anyone is interested.
....rather than a datalog, couldn't you simply check your dyno/HP numbers without the filter/tube/intake on it? -not that there's a good reason NOT to run a DL....
I've got an AWESOME deal on a Holley 58.....early style....if anyone is interested.
....rather than a datalog, couldn't you simply check your dyno/HP numbers without the filter/tube/intake on it? -not that there's a good reason NOT to run a DL....
If it were LT1 style with the LT1 throttle cam, IAC and TPS, I would be all over it for my Indmar Marine intake going on my L31. The Indmar manifold actually has 52mm holes in it. I suspect they were not using the stock GM 48mm TBs on them.
Well the results are in. Im not dissapointed or surprised but I didn't get a chance to pull the intake tube off for second dyno run and didnt get a chance to data log cause old ibm laptop takes too long to boot up. 420 hp 440 tq with heavy 19" wheels(70# ea.) which can drop dyno # 35 hp or more compared to light 17's or 15 " drag wheels.
Previous dyno numbers in 2006 were with 3.23 or 3.42 gears in 4th gen rear on light 17" wheels with an aluminum driveshaft afr's in the low 12's.
Now its got a ford 9" -35 spline 4.11 gear steel driveshaft heavy 19" wheels but a larger TB. Peak HP and TQ are just about identical. With the new drivetrain losses if it had the old rear & wheels etc, im guessing it would have been in the 450-460hp and 470-480tq range. Both were on dynojets at similar times of the years so temp change isnt much of a factor yet every dyno puts out different #'s. Ive seen cars lose 20 hp & tq on dyno with 15# heavier wheels
03-21-2019, 10:55 AM
