Datsun Deron

I haven't dyno'd my car but in my opinion 250 to 300 hp should be very attainable. I'd say anything more would be pushing it and need the addition of meth injection. If you havent purchased a turbo already I suggest going right to the t3/t4 turbo right away, I wish I would have... If you have it built I'd say run the setup and see what happens (but then again im cheap). The reason I went with flat tops and p90 was because I couldn't get anymore power out of my f54 (flat tops) and n47 head combo. I didn't want to pay another $1000 to rebuild a bottom end again with only 15,000 miles on it. I've been very pleased with the setup I've got, great power for daily driving.

arrang - I am running a 180 degree thermostat at the moment, good to know about the 160 degree thermostat. I just picked up a 3 row aluminum radiator a couple weeks ago but haven't installed it yet. It's on my todo list. Excellent suggestions. I'll add a lower thermostat to my shopping list. six shooter - The sensor is the open GM sensor pyro - thanks , Im hoping next year for some meth injection maybe. What are your thoughts on a 90 PSI pump? Or do I have to get the expensive 200 psi ones? Ryaapp2 - great read thanks for all the info.

@ letitsnow - Thanks for the info thats very interesting and a relief. I'd be curious to see now what happens on a 1st to 4th run. @ dexter72 - Good to know I will install an NA cam as soon as I can. I can really feel the power start to drop off around the 5000-5500 mark so that should help. I'll get to a larger turbo one of these days . @ six_ shooter - I'm am using the typical GM sensor. Great info on your setup and regarding not running an intercooler. 180 and 190 is getting up there wow.

Well I managed to get out and do some data logging yesterday morning and had some interesting results. I'll have to retract my previous statement about this being an FYI post as I've now got technical questions... I did a 3rd and 4th gear pull to around the 5300-5500 mark. -The lowest IAT that MS saw during the drive was 58 which is consistent with the weather network. -At the beginning of the pull @1800 rpm my IAT's were 64.5 (first screen shot) -At the end of the 3rd gear pull my IATS were at 87 degrees (second screen shot) -From here on out the IATS just keep climbing and climbing -At the end of my 4th gear pull my IATS were at 102 (last screen shot) -I wasn't able to get into 5th since the speeds were getting up there. I was very surprised to see the IAT's continue to climb until I let off the throttle. In my mind I thought it would level off somewhere but there was no sign of that. I'm just wondering if the readings from this sensor are actually accurate. The sensor has a potential of getting heat soaked from external sources, radiator etc. That being said I can't see it getting heat soaked that fast when the car is moving I've just seen heat soaking at idle. My turbo has a heat blanket and my manifold is wrapped as well. The only potential candidate I could see would be the radiator. Also when I let off the throttle between gear changes the IAT temps did level off. So that must be an indication that it is accurate? Have others seen similar results where the IATs continue to climb on runs with multiple gear changes? As far as I can tell there are two major issues that need to be addressed. The air filter is pulling in hot air behind the radiator. (im not running a shroud anymore like the picture below since I'm running a pusher style fan now). And the poor placement of the intercooler with no ducting. I also need to change the bins in my timing and VE table as im getting into the 180s for MAP at times. The picture below shows where my IAT sensor is (it's on the bottom of the pipe) right before the throttle body. It looks like I've got some changes to make and more data logging to do.

@ roger280zx - My apologies if you or anyone thought this was a thread about problems with my tuning or timing, that was not my intention. I made this post entirely just for the record incase anyone else was dreaming of running flat tops and a turbo, perhaps I wasn't clear. From what I've seen there isn't a whole lot of information out there regarding this setup so I thought I'd add my experiences. Most forum threads say to avoid this configuration all together and I'd like to prove that it can be done with decent results. Also with what I've read regarding my combo these results are fairly typical (low boost and retarded timing) so I really wasn't surprised with my findings. That being said I absolutely appreciate everyone's input and will definitely make use of the suggestions that were said. I agree if I can squeeze some more timing out of the thing I'll have even more fun. With the suggestions you've made regarding the intercooler location etc it could save me the hassle and cost of buying a meth kit in the future. @ letitsnow - I'll try to do some logging next time I'm out and let you know the outcome. I'll see if I can take off a little early for work tomorrow .

@ arrang - Thats a great point, I'm running the stock 280zx turbo camshaft I can't confirm the stamp on it. I've got quite a few spare non turbo cam's laying around. I'll take a look to see if I can find an A cam. I do have an aggressive non turbo reground cam but I dont think that will help me much since the turbo is sized so small. @ letitsnow - Good to know about the other plugs, next time im due for a replacement I'll be sure to look into those. The car feels great, pulls very nicely with the current setup. Plenty of power through the full RPM range. Unfortunately I've never been in a low CR 280zx yet to compare the difference. @ roger280zx - I'm thinking I'll try to calculate the intercooler efficiency with the setup as is. Then later I'll add some ducting and compare the differences. I don't think I'll change the angle of the intercooler this summer, if I do it might be more of a fall/winter project. (summer is a busy time for me). The current setup in the car feels great so I'm not in too much of a panic to change anything. @ dexter - I'll also close the gap to 25 and see how that helps. Thanks again all for the input, I'll try to provide some updates to this thread when I can.

@ Gollum - You didn't come across rude at all. I'd be very curious to see what would happen with 110 octane as well. @ Dexter - Thanks for the heads up on the lower bins. I noticed the stock turbo guys were running in the 40's and made it a little conservative just incase. I'll be sure to adjust those next time im tuning. As for weather here we do get some pretty hot days through July to September ranging anywhere from 86 to 104 degrees (when we get the real heat waves). I haven't tried closing the spark plug gaps yet, and I am currently running NGK plugs (two steps colder). We had some detonation issues when I first did the swap. Would two steps colder be too cold? I could possibly run 1-2 degrees more timing but pulled it back for the added insurance. @ roger280zx - I had originally tilted the intercooler so more of it was being hit by the opening in the air dam. Ideally though straight up and down, further back with some ducting would be the ideal way to go. I've actually been very curious to calculate the efficiency of the intercooler with the way its currently laid out. I should get on that. I might also look at ducting in the near future. @ pyro - Thanks for confirming the 8.8:1. My very scientific calculations came from information from this forum or zar.com.

@ BluDestiny - The engine pulls great with flat tops and turbo. I've been really happy with my setup. I originally did a non turbo build, then converted to MS, then wanted to turbo but was too cheap to pay and have another bottom end rebuilt. I figured I'd run her and see what happens, so far so good. If I did another turbo L28 build I'd still likely shoot for either a stock compression ratio or closer to 8:1 maybe. Good luck with the build! If you need to steal any timing or fuel maps just let me know and I can send it your way. @ letitsnow - That sounds about right from what I saw on the tuning/map sharing post on hybridz. The stock turbo motor is a completely different animal from this configuration.

Randy - my air fuel ratios are 11.5-11.7. The injectors have not been flow tested. Gollum - ill check the plugs when I get a chance Letitsnow - I could hear the ping by ear driving the car. Then we pulled the timing back 2-3 degrees for a safety margin I'm honestly surprised to see much concern regarding my results. From what I've read regarding my configuration I thought my results are pretty standard. Keep in mind I'm running non turbo flat tops and a p90 head. This setup brings my compression ratio way up around the 9:1 mark instead of the low factory compression at 7.4:1. Should I be able to pull more timing? I thought most people shy'd away from this setup for that very problem.

Sorry I should have mentioned in the post incase it got missed in my signature. I'm currently running a Spearco intercooler with MS-2 and EDIS Ignition.

Hi all, I thought I'd post my findings on tuning my car for the archives. I've been running flat top pistons, a stock turbo from an 84 300zx (same size as a 280zx turbo), 7 psi and a P90 head for a couple years now and decided it was time to start turning up the boost. I purchased a manual boost controller from ebay and installed it last weekend. I think it cost around $20 dollars. The hardest part of the tuning was getting the boost set properly on the manual boost controller. Mine was pretty sensitive. 1/2 a turn made a difference of 3-4 psi. For the first few full turns until you find the sweet spot it made no difference at all. After some very brief 15 PSI spikes I was able to get the thing set to 10 PSI (where i wanted it). Once we started tuning with higher boost the flat top and p90 combo becomes a detonation machine. The most timing I could run at 10 PSI (165 KPA) was 14 degrees. The one other restriction that might affect my tuning is the fact that my air filter is located behind my radiator. I'm hoping to relocate this in the near future and will post again later if this allows me to advance the timing any further. As for a power difference it was hard to tell on the butt dyno since we were tuning while driving uphill (where I drive its primarily flat) but I do believe that the car is faster despite having to pull so much timing out. I think I will likely leave the car at 10 psi for now until I can get my hands on a meth injection kit. But then again that little knob is just waiting to be turned . Edit - I should note I'm also running 94 octane fuel Here's my ignition table to date:

Well I wrapped my manifold last night and so far so good. I actually wrapped the manifold in the car with some old 2 inch header wrap that my father had kicking around. Unfortunately I don't know the length but I used the entire roll. It was a bit of a pain to get installed and took about 2 hours. It would have been a breeze had the manifold not been in the car...The header wrap roll was already cut into two very long pieces so that helped make it a little easier to fish in there. I would just wrap the pipe and fish the rest of the wrap out the other side then repeat until completely done. I was able to wrap cylinders 1 and 2 in one piece, 3,4 and 5 in one piece and 6 in one piece. I wore gloves, long sleeves, a dust mask and eye protection. Even with the long sleeves I still managed to get some of the fibers on my arm. I took a shower and tried to wash my arms best I could but it was still itchy going to bed. My advice would be to wear long sleeves and tape your sleeves to the gloves. I also had some scrap 1 inch wrap sitting around and I used that for the downpipe. As for the turbo blanket I purchased that off ebay from a seller called "speedmotoring" for $43.95. It was incredibly easy to install. I had to add a little slit for the wastegate arm but that was all. Its held on with two metal springs. For the metal zip ties those were also purchased off ebay from a seller called "l88_tools" it was 9.99 for 12 ties and I purchased two packs just incase. I didn't want to pay the local price which was over triple the cost. I ended up using 4 ties for the down pipe and around 10 for the manifold. For cylinders 3 and 4 I had to connect two of them together to make it fit. After the install the underhood temps are MUCH cooler, I also found that the turbo spools up sooner and faster. I wish I had done some datalogging of the before and after but unfortunately don't have much for before datalogging since I've switched computers. Here are some pictures:

Rain would be free water injection

I purchased a CX Racing intercooler pipe kit from ebay for mine from a seller called "Just-Intercoolers" he had an auction where you could pick 8 or so pipes for a set price (whatever bends you wanted). Once I got them it took a few hours of cutting and aligning but im happy with the result. The only downside is I'd prefer my air filter to be in front of the radiator or pull in cooler air somehow. Since all the pipes are on one side of the car it makes it tough to fit another one through there. I might look at building a box around the air filter to pull in air from under the car. My intercooler is a spearco same side unit as well.

Thanks for the info Gollum you make some very good points, especially regarding timing. I suppose comparing flat tops to dished pistons is indeed apples and oranges. The million dollar question for me is if I keep turning the boost up and retarding the timing at what point does it become worthless. The only real solution is to spend some serious time and money playing on dyno to find the answer. As a side note I also ran an MN47 head with flat tops for a few years. The flat tops with p90 head and turbo has been far more fun .