hey guys,
new to forum and have a few questions. Just bought a 98 sunfire gt with plans of turbocharging it this spring. Right now im trying to figure out what i have as its been slightly modified already. What i was told by the previous owner is as follows: " it has coates cams, gtp fuel pump, bigger injectors, and a tune" Unfortunately im not sure how to verify this information. firstly what are these "coates cams"? i cant find any info about these whatsoever. they apparently have "more lift, near same duration" also the "gtp fuel pump" i understand the idea of more flow but wont the stock pressure regulator be regulating it back down to stock anyways? is there any way to confirm its been tuned? ive hooked er up to the scanner and everything looks alright on the datastream aside from my long term fuel trim at -20% and a p0420 "catalyst efficiency" because the cat is gone, will this be causing issues or is the second O2 only for catalyst efficiency monitoring? thx for all your help and look forward to being part of the forum.
a few things i forgot to add about the car, some pertain, others dont. 2 1/2 inch exhaust, kyb adjustables & eibach progressives, superlite 17's wrapped in 235/45/17's, and a aftermarket clutch.
sure he didnt mean CRANE cams? if so that could definitely be a possibility.
I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
-Z Yaaaa- wrote:sure he didnt mean CRANE cams? if so that could definitely be a possibility.
not sure, might have been a "t9" typo. Im in the process of asking. Figured id might as well get some software to start learning the process of tuning so i got the hptuners suite mpvi pro and a dynojet wideband today... used with 8 credits left bringing my budget build total to 2100 total including a new compustar 2 way alarm/remote start which i will be installing next week.
Probably Colt Cams if it was a t9 typo.......seems pretty close.
if it was tuned prior, they did a horrible job. Most tuners would turn off the p0420 code. i wonder what else they didn't do.
On the other hand, the cams and the "bigger injectors" (what size, are they Green, possibly LSJ injectors), would require a basic tune to run half way decent.
What you need to do is:
* Find out the exact lift and duration of both cams... the term "twin cam" is not a true statement as the LD9 cams had different specs between the intake and exhaust...
* Find out if the lifters and valve springs are 33mm or 35mm (They will probably be 33... unless you have something like.410, .430 lift cams)
* Find out what injectors are in the car, stock ld9 injectors are 28lbs ... the injectors that come with the m45 supercharger kit are 33lbs, and LSJ injectors are 38lb... With your mods, going any higher than 38 would be unnecessary, but i get the feeling the guy that built the engine before you did not exactly know what they were doing...
If you cannot find out this information, I'd replace the injectors based on your build, and then use your HPT to reset the injector constant. if i remember correctly (and those who tune on here feel free to correct me), the stock injector constant is .20252 .. now yours most likely won't be set to that if the pcm has in fact been tuned. You should be able to find some calculations in the tuning forum that will calculate what constant you'll need based on the injectors you have. Not knowing what injectors you have is going to hurt you hard for tuning.
As for the cams... you can pull them out and measure, you can replace, or you can roll with it and not know... You'll spend a little more time figuring out your power band since you don't know how much more lift over stock... If they are like *secret* cam sized, you'll notice very little difference, but if they are HO or larger cam sized, you'll notice your power band somewhere in the range of 2500 - 8000 RPM. My Crane Cams are .430 lift .222 duration intake and exhaust.
When it comes time to boost the car, the boost forum will be able to help you out much more than this forum, the N/A All Motor Performance forum. There are plenty of stickies and write ups over there that will help you get started.
correction - ho cams in LD9 really only effectively rev to about 6500. secret cams are around 6000. (see my registry for dyno graph of secret cams)
paul's graph (open bills/stans header):
http://i136.photobucket.com/albums/q162/paultjepkes/Picture.jpg
I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
Really... my .430 cams reved up to 7200 and was still climbing on the dyno... (my statement said HO or larger)
yep. gotta remember, they are only stock cams LOL. with cranes i could see it because they are actual performance cams.
I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
Yeah brad but in a 2.3 they were rated to like 7k from the factory.
besides the .020 in lift and the .010 in duration... what exactly is the difference between GM HO cams and Cranes... what makes them "performance" besides the change in lift and dur?
overlap, ramp rates. all kinds of ish.
I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
Im sure they could be quite a bit different. They could have different timing in relation to top dead center which would affect the rpm range. The lobe center angles could be different, affecting overlap, which also affects rpm range.
they are different and i would prove it right now if i could @!#$ find brandon's comparison sheet!!!!!!! ARG!!!!!!!!!!
I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
i decided to pull the fuel rail to check out those injectors and they are stock.. go figure lol what a pain trying to re trace the prior owners steps... 2 of the 4 injector orings were torn so i replaced them and now its running pretty rough. on a cold start it seems like its just pourin the fuel in because it needs a little throttle to get going followed by a rough idle and rich rich smelling exhaust. could higher fuel pressure be causing this or will the stock fpr be cutting it down to stock pressure regardless of the fuel pump output? widebands going in this weekend or next and i should be able to sort more of this out with my hp tuner. as for the cams can i get that "valve" cover off and measure them that way or are they coming out to measure them? would prefer to stay away from that timing chain/ front cover after my water pump experience
j body enthusiast wrote:i decided to pull the fuel rail to check out those injectors and they are stock.. go figure lol what a pain trying to re trace the prior owners steps... 2 of the 4 injector orings were torn so i replaced them and now its running pretty rough. on a cold start it seems like its just pourin the fuel in because it needs a little throttle to get going followed by a rough idle and rich rich smelling exhaust. could higher fuel pressure be causing this or will the stock fpr be cutting it down to stock pressure regardless of the fuel pump output? widebands going in this weekend or next and i should be able to sort more of this out with my hp tuner. as for the cams can i get that "valve" cover off and measure them that way or are they coming out to measure them? would prefer to stay away from that timing chain/ front cover after my water pump experience
the last two bolts of the cam tower cover are behind the cam sprocket. there is no way around it.
so i took the fuel rail out to inspect my injectors.
they are "RP"
2 numbers - 2178 and 17091654
as far as i can find they are stock searching through injector sites
as for the cams i have not pulled them out to measure them, figure ill hold off on that till the next time the motors out as its my daily right now because my truck gets 12 mpg
i did however do a compression test the other day just for the hell of it to make sure im starting with a decent platform and my numbers were a bit suprising. 210 +/- 5 psi accross the board. Is that not really high for what im working with?
nope thats right on par with most LD9's, actually.
I choose the technology built for land speed records... not the technology built to save on emissions and gas mileage.
good to know.
got my wideband 02 bung welded in finally and my fuelling issue sorted out (regulator diaphram was torn) just chasing an upstream exhaust leak prior to setting up the dynojet
