SSflyer Posted March 31, 2007 Share Posted March 31, 2007 Got the car Dyno Tuned at Extreme Motorsports in Tempe yesterday and found out why it had failed smog. It appears that every adjustable setting was way off. First pull showed only 275ish hp, but he had shut it down early. The maf was all gummed up (along with my shorts at that point!), so after cleaning the maf the next pull was in the 330 range, and the final numbers are 347hp, 344tq. I was hoping for more, but the numbers are what they are. I guess that for just a hotcam and headers that's a reasonable increase over stock. I'm glad I hadn't been out hammering on it before the tune because the air/fuels were like 16:1 above 3k rpm. BUT, there was some hammering later last night and it appears than tire spin is going to be a problem, he said with a big grin on his face. So now I'm wondering how you 400+ hp guys even drive your cars. I have 275's on the back of mine, and it spun those up just punching the gas in second and spun them with no problem in third. It seems that adding another 50+ hp would be like driving a 280 death wish. Now I can look forward to getting to the track to see what sort of times it can do. Gotta get there while it's still cool out... Quote Link to comment Share on other sites More sharing options...
280Zone Posted March 31, 2007 Share Posted March 31, 2007 Glad to hear you got it dialed in. Tire spin has also been my most problematic area. The sticky track will help some and you can treat the tires too for a bit more bite. The next Firebird night is April 13th. Hopefully I can make that date as well. Quote Link to comment Share on other sites More sharing options...
piston Posted March 31, 2007 Share Posted March 31, 2007 nice numbers. i took mine for a spin around the block today for the first time. it looks like im going to have traction issues also. i cant imagine anything over 300hp and i only have an lt1 with a hotmcam package...rpm sounds like it clibs so fast, i get worried and throw it to nutral asap... Quote Link to comment Share on other sites More sharing options...
blueovalz Posted March 31, 2007 Share Posted March 31, 2007 This was one reason I chose the lower torque, higher horsepower build on my motor. It has a pretty broad torque curve and lacks a lot of bottom end grunt. Being only 289 CID, and with 315s in back makes is pretty controllable. It's turned out to be pretty nice in that I don't have to babysit it all the time on hard pulls, but it still kicks out in a corner when I want it too. Quote Link to comment Share on other sites More sharing options...
deja Posted April 1, 2007 Share Posted April 1, 2007 LOL, did you really think 350 HP in a 2700 pound car wasn't going to have traction issues? Looks like you've dialed it in pretty well, congrats. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted April 1, 2007 Share Posted April 1, 2007 You shouldn't be disappointed in those numbers IMO. That's 400+ at the crank and that doesn't sound too bad to me. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted April 1, 2007 Share Posted April 1, 2007 350rwhp is nothing to sneeze at. Remember every engine combo and dyno will read different. Depending on the amount of wet weather driving you will be doing in the car, you may want to try a pair of drag radials for the street. Laying black lines on the pavement is fun, when you are TRYING to do it... Quote Link to comment Share on other sites More sharing options...
aziza z Posted April 2, 2007 Share Posted April 2, 2007 nice. wish i had the problem of tire spin haha. Quote Link to comment Share on other sites More sharing options...
z_cars_rule Posted April 2, 2007 Share Posted April 2, 2007 350rwhp is nothing to sneeze at. Remember every engine combo and dyno will read different. Depending on the amount of wet weather driving you will be doing in the car, you may want to try a pair of drag radials for the street. Laying black lines on the pavement is fun, when you are TRYING to do it... Because my car wont be an everyday car, i will be running DRs on mine, but I have no prob having 2 sets of wheels, and swapping them over regularly. sounds like a good package you have there, still VERY streetable Quote Link to comment Share on other sites More sharing options...
m1noel Posted April 2, 2007 Share Posted April 2, 2007 I don't think those numbers look bad at all. I have yet to get mine in to dyno it, but tire spin is a problem right now. I went to an auto X for the first time in about 13 years-on my 225mm street tires-this weekend. I think I beat everything that wasn't on race rubber, and almost nothing that was. It was fun though. Mike Quote Link to comment Share on other sites More sharing options...
ULISES Posted April 2, 2007 Share Posted April 2, 2007 Congrats, Those numbers seem fair for a LS1 engine. I have seen a few pull close to your numbers with the few mods you have. I too have a tirespin problem with my 225/45/17 tires, Only above 1/4 of throttle. I find it amazing how wasy it is to drive even under the rain if you drive it normal. I'm currently working on getting a different wheel/tire package, I want to go with some 17 x 8 or 8.5 wheels with a 245 dragradials. Quote Link to comment Share on other sites More sharing options...
SSflyer Posted April 3, 2007 Author Share Posted April 3, 2007 I'm running 275's on 9-1/2 rims in back and have been thinking of dropping to 255's because of clearance problems, but I don't want to loose the traction. I have Nitto drag radials on my Camaro and they hook better so I'll probably go to those at the next tire change. I wish I could find some 275-35 tires. All my problems would be solved. Horsepower is still a pretty nice problem to have though! Quote Link to comment Share on other sites More sharing options...
a6t8vw Posted April 3, 2007 Share Posted April 3, 2007 350-400hp is what im guning for with my build, i think anything over 400 hp for a street Z is a death wish haha I was able to fit 265/35-18 tire 18X9.5" +38 offset with a 1.5"adapter (35mm) i machined on the rear of my 280.. not sure yet how traction is going to be with practicly Zero sidewall...we'll see soon Quote Link to comment Share on other sites More sharing options...
1 tuff z Posted April 4, 2007 Share Posted April 4, 2007 i ran 330 hp, 360 tq-as measured by a brand new dynojet last spring. shorty headers, ls1, no other mods. yes, traction is an issue but one i happily address! Quote Link to comment Share on other sites More sharing options...
SSflyer Posted April 5, 2007 Author Share Posted April 5, 2007 Well, the newest news is that I failed emissions again! The idle hc reading was almost 4 times the limit (875ppm to a limit of 250ppm). I called the tuner to see if they had missed something, but his records showed every trim was spot on. So.... I went to an emissions specialist place today and really got schooled on LS1 engines. Turns out that all the stuff I've done to make the engine run cool are really problems. They said to reconnect my MAF water jacket, and to loose my 160 degree t-stat and put the stock 180 degree unit back in. The engine was flipping between open loop and closed loop operation because it couldn't tell how hot it really was, and open loop equals very rich. They also said my intake air sensor was bad, adding to the temp problem. AND the biggest fubar was that the shop who reflashed my computer last year was supposed to turn the back two O2 sensors off, but they didn't. So now the front sensors are reading at one end of the scale, and the rears are at the other extreme because there's nothing plugged in to them. Again the computer is confused on what to do, so it dumps in more fuel. Oh, and the two O2 sensors that are on the car are slow responding and should be replaced. So now I need an IAT sensor, new O2's and simms. Another $500 or so to piss away. I sure hope all this works, cause I'm about out of options and patience (not to mention money!).... Quote Link to comment Share on other sites More sharing options...
280Zone Posted April 5, 2007 Share Posted April 5, 2007 You are getting close. I have been in your position and it seems as though it will never end. Remember you have years of work into the car don't let the last few days get you down. Quote Link to comment Share on other sites More sharing options...
Guest jmsmith37 Posted April 5, 2007 Share Posted April 5, 2007 i dont know what type of power im putting down yet but i have the little stock tires and i was putting down 100ft lines of rubber trying not to spin the tires what rim type are you getting those 275 and up on i want a bigger tire but i am thinking about doing a 12bolt and i dont want to waste to much money anything on that four lug pattern? Quote Link to comment Share on other sites More sharing options...
m1noel Posted April 5, 2007 Share Posted April 5, 2007 I too have to go visit the emissions folks this month. I hope I have a little better luck. I read before I started that changing the t-stat was not going to help and that these motors like to run hot. I am not having any cooling problems at all with the stock t-stat. I am using the JTR radiator, and the fan /shroud from JCI. I believe it is from a ford van. I am also using the predator tuner/programmer, and they have been really good to work with, writing me custom programs whenever I have needed to change things. I have faith that it will pass. I hope, I hope, I hope. Mike Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted April 5, 2007 Share Posted April 5, 2007 Well, the newest news is that I failed emissions again! The idle hc reading was almost 4 times the limit (875ppm to a limit of 250ppm). I called the tuner to see if they had missed something, but his records showed every trim was spot on. So.... I went to an emissions specialist place today and really got schooled on LS1 engines. Turns out that all the stuff I've done to make the engine run cool are really problems. They said to reconnect my MAF water jacket, and to loose my 160 degree t-stat and put the stock 180 degree unit back in. The engine was flipping between open loop and closed loop operation because it couldn't tell how hot it really was, and open loop equals very rich. They also said my intake air sensor was bad, adding to the temp problem. AND the biggest fubar was that the shop who reflashed my computer last year was supposed to turn the back two O2 sensors off, but they didn't. So now the front sensors are reading at one end of the scale, and the rears are at the other extreme because there's nothing plugged in to them. Again the computer is confused on what to do, so it dumps in more fuel. Oh, and the two O2 sensors that are on the car are slow responding and should be replaced. So now I need an IAT sensor, new O2's and simms. Another $500 or so to piss away. I sure hope all this works, cause I'm about out of options and patience (not to mention money!).... You know that is actually pretty encouraging that the emissions inspectors were first that knowledgeable and second that helpful. The changes they suggested will not only help you pass smog is should make your motor run better. BTW, you don't need rear O2 sims. Send the unit back to the guys who flashed it in the first place and make them fix their error. If you ask nice they shouldn't have a problem making good on that. Quote Link to comment Share on other sites More sharing options...
SSflyer Posted April 5, 2007 Author Share Posted April 5, 2007 Ok, I've done some looking around since yesterday at it appears I can get the parts I need for less than $200. I also ordered a pair of the Maxima rear brake brackets and they came yesterday, so now I can swap out my homemade units. (Courtesy Nissan in Dallas still sells these things for $54ea!) Hopefully all this stuff can get done over the weekend and retest again next week. And actually it was good news that they found some problems. It would have been WAY worse if they said everything was good and there was no options for getting it legal. jmsmith37.... I have early 80's Mustang Cobra rims, 17 x 9-1/2 on the back. Quote Link to comment Share on other sites More sharing options...
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