81280zxtc Posted January 25, 2005 Share Posted January 25, 2005 Fellow Z buffs. The shop where my Z is being worked on finally finished the fuel system, and it was dyno time. Here are the results: 1st run: 1.0 bar. 237hp / 243 lb/ft torque 2nd run: 18lbs boost 284 hp / 282 lb/ft torque 3rd run: 21lbs boost 315hp / 310 lb/ft torque That was it for Saturday. Should I be estatic? After all the mods, I thought I would be somewhere around 400hp, but I guess I'll settle for what I have. The tuning was done on 112 octane race gas. The Haltech was on the money with the exhaust. Clean, no lean or rich condition. I wanted to try bumping the boost to at least 25lbs, maybe 28 once I get the EVC dialed in right. Any advice? I do have a HKS metal head gasket, and ARP head bolts, so I'm not worried about having a little too much, but I don't want to break anything. What to do? Thanks to all who will reply.. Rob Quote Link to comment Share on other sites More sharing options...
violacleff Posted January 25, 2005 Share Posted January 25, 2005 What are your mods? Quote Link to comment Share on other sites More sharing options...
81280zxtc Posted January 25, 2005 Author Share Posted January 25, 2005 Lets see what I can remember Haltech E6K enging management, Turbonetics T60-1 Ceramic Ball Bearing Turbo, Cartech Intercooler & blow off valve, 12 injectors 6 primary-6 secondary staged, mild port and polish head, TEP throttle body, HKS cam, MSD 7AL2 Ignition amp w/ MSD 8251 ignition coil, Aeromotive fuelpump, fuel pressure regulator w/ 2 direct feeds to injector rail w/ seperate returns, HKS EVC Pro, Tial 38mm wastegate w/ 1 bar spring, 3" downpipe into 2.5" HKS exhaust I think that's it... Quote Link to comment Share on other sites More sharing options...
slownrusty Posted January 25, 2005 Share Posted January 25, 2005 Wow...you have alot of choice and hight dollar parts on there....how do you have the extra 6 injectors plumbed into your intake...HKS stop making L6 cams along time ago! I bet if you went all 3" with your exhaust and got rid of the 2.5" bottleneck you will easily see 320+ wheel hp...if not more. You certainly are running some high boost numbers wow! Is your head or block O-ringed? Are you using ARP head bolts or the stud conversion kit? Another observation 1.2bar = 17.6psi, so how did you go from 237whp at 1.2bar to 284whp at 18psi - I'm confused... Any pics you can share...sounds like you have a very nice set-up. Yasin Quote Link to comment Share on other sites More sharing options...
81280zxtc Posted January 25, 2005 Author Share Posted January 25, 2005 The block is a stock block w/ an HKS 1mm metal head gasket. I do have ARP fasteners for the head. The intake was modified by Corky Bell who used to own/work at Texas turbo some many moons ago. It's actually very nice. My pics are posted on the photo section of the forum for anyone to view. I would appreciate comments or suggestions. Thanks to all. Rob Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted January 25, 2005 Share Posted January 25, 2005 I have to be honest, those numbers do not look like an L28's dyno numbers should. With a 60-1 you should be putting down WELL into the 400's on 21psi. Hell, I put down 399wtq on 20psi, on a stock motor, and stock turbo. You should be making 380wtq with 310whp. I would seriously check tuning, timing, or something. Having a 2.5" exhaust would increase the torque the car makes, because of the back pressure. I would check compression, and make sure the turbo is still good, along with plugs, and tuning. Something is definatly NOT right. Quote Link to comment Share on other sites More sharing options...
Mack Posted January 25, 2005 Share Posted January 25, 2005 Id have to agree with cronic. something doesnt seem right. usually the L28 puts down a LOT more torque than hp, for any HP level. i think JeffP is making 415 rwhp and 473rwtq @ 24psi. thats 100 more RWHP for 3 more PSI. Ive seen dyno charts of completely stock 20 yrl od 280ZXT's that put down 170rwhp at stock boost with JUST a 3 in exhaust. what are your air to fuel ratios like? I dunno man, sorry! hope you get it figured out. Mack btw, a complete stocker picks up about 20rwhp just by going to a 3 in exhaust. Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted January 25, 2005 Share Posted January 25, 2005 There could be many issues goin on here, one of which could be the turbo going bad. I don't know how old yours is, but when they begin to go bad, they quit making a lot of power. Quote Link to comment Share on other sites More sharing options...
Deep Posted January 25, 2005 Share Posted January 25, 2005 I don't know a whole lot about L6 engines, but your numbers don't sound fitting for an engine that size, the 2.2 4 banger in my Celica made 203HP at 7psi, and I kept it a little rich for safety. As suggested above, you may want to do a compression test and maybe pull your plugs to look for clues. Do you have an AF graph? The other thing that makes me wonder is what sort of tuning was done, you stated 112 octane, which means that the tuning shouldn't be too conservative. Post up your dyno sheet. Quote Link to comment Share on other sites More sharing options...
510six Posted January 25, 2005 Share Posted January 25, 2005 Were you tuning with a WB02?I have seen A/F reading that were WAY off due to a contaminated 02 sensor.The last time I was at the dyno my Tech Edge and their 02 were reading way off, I put my WB02 into the tailpipe of a brand new OBDII Toyota and it was 14.7 at idle...theirs was 12.5.They replaced the 02 and both units cycled together perfectly. As for an L series making more torque than HP my car on the N20 has always made more HP than torque 535 vs. 490.I would check the turbo for excessive sideplay, my bone stock CT26 turbo made 275rwh and 315fpt on the dyno and is only capable of flowing a fraction of what your turbo should.I have seen a number of Turbonetics turbos fail after only a short period of time on them. Quote Link to comment Share on other sites More sharing options...
Clifton Posted January 26, 2005 Share Posted January 26, 2005 Having a 2.5" exhaust would increase the torque the car makes' date=' because of the back pressure. [/quote'] It actually wouldn't. There is more pressure before the turbo than after it. Pressure after the turbo just increases lag. I wouldn't bother with bumping the boost up till you find out why you are down on power. What was your timing at 21 psi and your AFR? What's the turbine trim and a/r? You should be up atleast another 100 rwhp. Do you have a graph of the dyno? Quote Link to comment Share on other sites More sharing options...
81280zxtc Posted January 26, 2005 Author Share Posted January 26, 2005 I would seriously check tuning' date=' timing, or something. Having a 2.5" exhaust would increase the torque the car makes, because of the back pressure. I would check compression, and make sure the turbo is still good, along with plugs, and tuning. Something is definatly NOT right.[/quote'] The bottom block is brand new. Found it at a dealer about 6 years ago still in the factory crate. I have not checked compression, but the car idles smoothly, and there is no hiccup when you get on the gas. After the last dyno run, we pulled the plugs and they were clean, not black or white. The turbo is brand new, I've had it for about 18 months, and it was packed in its box until the day of install. I checked the shaft and it's solid, no play or wobble. I was wondering if there could be a leak in the intake or something. The stock "pop" off valve and boost regulator are still on the intake, but are not connected. I was thinking that those things are bleeding off intake pressure? Could I be right / wrong? Would I be better off capping/pluging them off? I was assuming that I would be making at least 400 hp at the rear wheels with all the mods and especially running on racing gas. The other thought I had was the wastegate was creeping boost. They were using a turbo xs manual boost control valve to actuate the waste gate, but I think with the EVC properly installed, the car should put up better numbers. What else can I check? I'll try to import the dyno sheets and post them...tomorrow... Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted January 26, 2005 Share Posted January 26, 2005 It actually wouldn't. There is more pressure before the turbo than after it. Pressure after the turbo just increases lag. I wouldn't bother with bumping the boost up till you find out why you are down on power. What was your timing at 21 psi and your AFR? What's the turbine trim and a/r? You should be up atleast another 100 rwhp. Do you have a graph of the dyno? Not tryin to start an argument or anything, and after this comment, i'll leave it alone. I have done the dynos myself at a friends shop, using both a 2.25 crushed, and a 2.5 mandrel exhaust, and it does in fact increase torque with a more restrictive exhaust. This was done on a turbo Civic however, not a Z car. I would assume, for the most part, the results would be similar. Although it's not relative to the topic at hand. So I'll leave it at that. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted January 26, 2005 Share Posted January 26, 2005 I would check for intake leak with a boost leak tester. Made a big difference in my car. The boost creep should be a problem with an external 38mm unit but either way the creep will make more power since boost will go up with rpm. With all that mods, tou should be making more power. What kind of dyno was it? Manual or auto? Quote Link to comment Share on other sites More sharing options...
Mack Posted January 26, 2005 Share Posted January 26, 2005 The stock "pop" off valve and boost regulator are still on the intake, but are not connected. I think we have a winner! doenst the stock pop off valve start to vent at like, 10 PSI or something? you have to remove it and plug the hole all together. If you do that, I bet it'll help A LOT Mack Quote Link to comment Share on other sites More sharing options...
Drax240z Posted January 26, 2005 Share Posted January 26, 2005 Uhh, yeah you can't disconnect the POV and leave it in the intake manifold... major boost leak! (over 8psi anyway) Quote Link to comment Share on other sites More sharing options...
81280zxtc Posted January 26, 2005 Author Share Posted January 26, 2005 I have posted the dyno results in my album...I can't seem to upload them to the message board... Please take a look and let me know what are your thoughts. Thanks. Quote Link to comment Share on other sites More sharing options...
Guest 240zJake Posted January 26, 2005 Share Posted January 26, 2005 wow this is a big pic..there you go though Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted January 26, 2005 Share Posted January 26, 2005 Couple of comments. Not saying there might not be a problem that needs addressing, but we are making the same classic mistake of comparing HP numbers from different dynos. Could part of the problem be the dyno/run? What gear was this pull done in? The graph is showing MPH not RPM and it looks like 5250RPMs occured at about 74mph. If this was 3rd gear with a 3.70 and 25" tire, 5250 should be more like 82mph by my calculation. Now if he is running a 3.90 it would be closer to the dyno sped and of course a 3.54 would make it worse. Am I off base or is this a consideration? Quote Link to comment Share on other sites More sharing options...
mtcookson Posted January 26, 2005 Share Posted January 26, 2005 Not tryin to start an argument or anything' date=' and after this comment, i'll leave it alone. I have done the dynos myself at a friends shop, using both a 2.25 crushed, and a 2.5 mandrel exhaust, and it does in fact increase torque with a more restrictive exhaust. This was done on a turbo Civic however, not a Z car. I would assume, for the most part, the results would be similar. Although it's not relative to the topic at hand. So I'll leave it at that.[/quote'] actually... its not really the size of pipe per se. its more of the design. its generally said that more back pressure increases torque however if you get a larger pipe and have it designed well enough for good flow you can actually increase torque as well. that's why with a lot of boosted cars you see the torque go up dramatically with a 3 inch exhaust system. it flows well enough to allow the torque to increase. something along those lines anyways. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.