TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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__________________ YOUR 90-92 CAMARO TACHOMETER BROKE? I CAN FIX IT. PM ME FOR DETAILS. SuperStreet in the making...It's a work in progress.
SBC, Forged internals, 215cc aluminum heads, 90mm TB, .589/.612 lift cam, Long tube headers, 3.5" exhaust. 9" Procharger. Powered by Holley HP EFI
That's a real wimpy cam there. Cam choice all depends on your chip tuning skills. Get into the tuning right now, once your good at it do the heads/cam swap and go with no less than an LT1 cam I'd say, preferably larger.
NO, lol, i dont think you want a .560 lift camshaft in a 305. If you are really confident that you can get your car tuned then i would go with something around .500 lift with a 214* duration at .05 lift and at least a 114* LSA.
That cam that can come with the intake manifold will not work on our cars. That cam is designed to work on TBI trucks which didn't have roller lifters. Our cars do have roller lifters, so you need a roller cam.
since the tbi motors do not have a ton of compression you can always go with a modern cam design that helps to build cyl pressures up a bit.
i am personally a big fan of comp cams extreme energy line of bumpsticks. they use modern lobe design to allow for greater charge volume and velocity.
since you are plannign to run a performer intake i would suggest you check the XE264HR. it will provide a huge gain in power across teh band, great average and peak torque numbers. it is a .487/.495 lift, 212/218 duration @ .050, and a 110 lobe seperation.
it will give you a nice noticable idle, but nothign choppy or radical.
you will need to do soem chip tunign to compensate for the cam, but you will have to do that for any good cam, so no big deal.
it will be a strong cam taht you can shift around 5600rpm and still daily drive on without any problems.
You can live with it but your speed density TBI setup will have some trouble. Even that cam on a 110 LSA is going to be pretty tough to tune in at idle I would think. I wouldn't go any larger than NJ's recommendation, at this time, at least.
The 270HR would make your car run like poo without tuning. Probably wont even really be drivable. I too like the cams with more aggressive ramp up. I have one of the old school lazy cams with lots of advertised duration, something like 280. With my 8.5:1 compression, the motor is weak below 2000 rpm and it bogs a bit in high gear at low speeds. Id put my vote in for either the 258HR or the 264HR with 112 LSA. 110 would probably be fine, but 112 may be easier to tune around idle since the vacuum signal will be a bit more consistant. If your not planning on tuning the car yourself, you might as well not even bother doing any of the mods. After what I went through with mine, I wouldnt even touch another TBI setup if I couldnt alter the ecms tune. These cars just seem to run like puke if you dont tune them after mods. After my mods, I even considered retrograding to a rochester Q-Jet and non-CC HEI dist. before I bought the stuff to program chips.
and plus you have smog to worry about, i would just go with an LT1 camshaft with 1.6 rockers, this will give you a lift at about .480, a duration of about 205* and a large lobe separation which will help alot with tuning. believe me, if u put in that camshaft, sr torque heads, and a performer intake, you will get some very nice gains. Dont think you have to get the biggest camshaft, the most expensive heads, and the best intake in order to be satisfied. I am happy with my car now and i have yet to touch the heads or camshaft.
you arnt going to be able to get HP numbers to compare, the cam that he listed is going to be very hard to tune and more than likely your car will run slower because of the bad tune. If you get a LT1 cam, 1.6 rocker, heads and intake you will be looking at some very good performance gains. Going with a smaller cam and making the car easier to tune will be a great trade off, i dont want to see you 3 months later complaining that your car runs like crap and you cant pass CA smog. You will benefit from a more computer friendly cam.
Ok, first off, you have a 305, those RPM ranges are not accurate, add 1500 rpm to each number, and this will be more accurate for a 305.
the 270HR is too much cam, unless you are planning on spinning to 7k, in which case i hope you have a valvetrain up to the job.
I do like the 264HR cam, it is fairly aggressive cam for a 305, it will be some work to tune, my one problem with that cam is the 110* LSA, typicaly the computer controlled cars, like 112-114 LSA, it keeps them a little happier. Although i would have to run the numbers, with a cam that only has 212* duration, the overlap, even on a 110 may not be anything that will cause a huge problem. if you have Zero tuning practice, start now, don't wait. the learning curve on a cam like that is very steep, if you start now, you will know how to manipulate the numbers.
Like I mentioned before I would do suspension mods first. No tuning with be required and you will see nice gains. I would get a posi unit, 3.73s, lca's, panhard rod ect....
That and your nitrous should yield some good times. Plus you won't have to worry about smog or tuning.
Dimented....I know how you feel. Our cars were exactly the same. We even put the same GM goodwrench engine in them. I was going to go TBI...then last minute I suddenly found myself ordering a holley carb, intake, proform distributor, FPR, ect. At first I had no idea what to do with the carb. I knew I had no idea but I did it anyways. Even when my carb was out of tune it didn't run that bad. Now I know what I'm doing and I really like it. Only problem with carbs is they don't run well when they are cold and they like to stall out when you brake very hard. Oh well.
since we are talking about cams.. im still deciding what cam to use with the endgine im goign to build.
thinks to keep iin mind has to be smog friendly and not terrible to tune but goor midrange power, i have a 2400 stall, heres what i ahve for now
i was thinking l98 cam but wanted a bit more pwoer then that. let me know your sugestions on this combo.
l98 short block ...30 over
ported l98 heads
holley tbi intake
holly 670 tbi
cam ???
compression aournd 10:1
#65 injectors
high fllow fuel pump
lots of tunning of course!!
__________________ 91 RS mods: 342 posi rear, spohn lca's and panhard rod with relocation brackets,ls1 driveshaft, built 700r4 trans with slp 2400 converter, b+m trans cooler, stewart stage 2 water pump, 1 5/8 edelbrock headers with 3' flowmaster exaust, 3 inch catco cat, i , msd distributor and msd wires, walbro 190 fuel pump, 58 mm throttle body, slp runners, ported stock intake. ac delete.
* Putting her together after 5 yrs of sitting . 350 tpi going in finally!
that there is no joke of a cam. should pull like a mother to about 6200-6400
with your combo, i would tweak a few things though. 1) intake, think single plane
and depending on HP levels, you might need larger than 65# injectors. the cam i listed should be a good fit in a 350. (i noted the 'lots of tuning' at the bottom, that is why a cam that large came into play, it will take tuning. but once you get it sorted out, hang on. That cam should easily make 350hp. with the right intake, and if the heads are sorted out. the 2400 stall should be just right for that cam also i would also suggest at the least 3.42 gears.