Pyro Posted September 4, 2007 Share Posted September 4, 2007 What heads are you using? What compression ratio? What carb and intake? What mufflers? With 131 mph and 2750 lbs that comes out to about 485hp. And that is with 180 shot of n20. So your engine is only making around 340 hp (410 crank hp). Seems a little low for a cam that big. what mph on the motor? 117, 118 mph? Quote Link to comment Share on other sites More sharing options...
zthis Posted September 4, 2007 Author Share Posted September 4, 2007 What heads are you using? What compression ratio? What carb and intake? What mufflers? With 131 mph and 2750 lbs that comes out to about 485hp. And that is with 180 shot of n20. So your engine is only making around 340 hp (410 crank hp). Seems a little low for a cam that big. what mph on the motor? 117, 118 mph? The 131 pass on NOS wasn't on NOS of the line Car normally runs 11.2 @ 120 MPH. Last race weekend i had a 11.007@122 and 11.05@123 air was cold and there was a tail wind. 10.75:1 compression, 750DP Holley Carb Team G dome with 1 inch pheloic spacer. Eldebrock Performer RPM Aluminum heads 64CC and 170 runners well ported. full length 1 3/4 hedman headers bolted directly to 3 inch sonic turbo mufflers with no tail pipes Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted September 5, 2007 Share Posted September 5, 2007 Nice launch by the way. I would tighten the front end down another link, and also install another rubber shim in the rear. Waisting energy by lifting and squatting, you will need to experiment with this. Build the engine rpm up more when leaving the line if the rear tires will hold. Shift point would probably be around 6500 rpm. Again this is something you can experiment with. I would also run royal purple engine oil ( synthetic oil xpr 5w30 ) fresh oil filter and only 4 qts of oil, like I said this is good for a 1/10. Weight savings - the saying is every 100lbs is good for a 1/10 as well. They say after you run the car once, drain the water from the radiator / engine. Pour in cold water with engine running is also suppose to be good for a 1/10. I have never tried this. Mechanical fuel pump verses electric pump. Less friction on engine means more power. Good luck on your venture. John Guys thanks for the posts some real good ideas i realize i won't need muchbut why stop at a 10.99. John at JNJracing take a look at the picture of my launch posted above do you think that is too much rear squat if so i'll add another round of rubber in the rear springs? Jap Tin i'd forgotten about shallow staging a few inches head start can't hurt either I think i can swing something of a cold air intake to the carb. I normally race with no breather so i'm not sure how that will all work out. i'm also considering a trip to the dyno just to make sure i'm shifting at the optimum RPM. Anyone know how many (if any) HP can be gained by switching from a mechanical to electric fuel pump? Any other ideas i'm racing saturday???? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted September 5, 2007 Share Posted September 5, 2007 Weight savings - the saying is every 100lbs is good for a 1/10 as well. whew.. so my little 50 pound speaker box in the rear wont hurt me that much.. 1/20 of a sec! lol. the weight helps w traction eh? (sandbagging!! haha) Quote Link to comment Share on other sites More sharing options...
Pyro Posted September 5, 2007 Share Posted September 5, 2007 I see, no n20 off the line. That makes since. Sounds like you have a good setup. But, I think you could use a little more cr and a little bigger set of heads. Maybe 11:1 cr and 195 afr's or maybe get some 210 afr's which would also work well on your future 406. I think you are at the limit for 170cc heads with trap speeds in the low 120's with 2750 pounds. Quote Link to comment Share on other sites More sharing options...
G.I.jonas Posted September 5, 2007 Share Posted September 5, 2007 They say after you run the car once, drain the water from the radiator / engine. Pour in cold water with engine running is also suppose to be good for a 1/10. I have never tried this. ????.. what exactly does that do to gain a tenth again? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted September 5, 2007 Share Posted September 5, 2007 cools the engine down.. keeps it at operating temp. rather than blistering hot and causing pre-ignition or worse detonation. so you can advance the timing slightly with a cooler engine Quote Link to comment Share on other sites More sharing options...
ragefear Posted September 5, 2007 Share Posted September 5, 2007 Yea, the only thing I know that doin the whole coolant swap will do is crack aluminum blocks... This I know... Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted September 5, 2007 Share Posted September 5, 2007 I agree w/Pyro. You have reached the limit w/170cc heads. Your engine package; all be it a good one is similar to the 5.0's when they first came out. Their cylinder heads were in the 135cc range. For a 302 displacement the 135cc heads were perfect stop and go rush hour engines. Throw in some NOS and they were fun. Put some 160cc aftermarket heads on and the engine came alive. So, what would have been the point w/a factory 5.0 if someone gave the engine a 280 solid cam and building the engine with 11.0:1 SCR and still keep the same cylinder heads? See the point I'm trying to make? Ratiowise (mathematically speaking) your engine the 355 w/170cc heads is the same set up as the 302 w/135cc heads. There is only so much performance you are going to get out of smaller intake port heads. Remember, the word "smaller" is a relative issue. Relative to WHAT? Relative to desired output and engine displacement. Your 170cc cylinder heads are great for a smaller normally aspirated engine. If you are going to use the NOS on a regular basis, w/the 355, then you need to have cylinder heads in the 195cc range: with all other engine spec's remaining the same as you mentioned earlier. If you decide to build the 406 and utilize the same cam specs, same SCR, and the NOS; then you need cylinder heads in the 220cc range. This would mimic 210cc's w/a port job. You can always count on about 10cc being added to the port w/a proper port job. If you decided not to use the NOS w/the 406 and wanted to run w/out probs on pump gas then the 210cc is spot on. Regardless of which way you go, those 170's are perfect for a peppy pure street engine and doesnt really do anything for you cam specs or your SCR. With your SCR and cam specs in mind, it sounds like you want a weekend warrior. Yet, your choice of 170's relative to your engine displacement equals a pure street engine. In other words, your cylinder heads are not matched to your cam/SCR specs or vise versa as in your cam/SCR are not matched to your choice of cylinder heads(?). With your cam specs and your chosen SCR relative to your engine displacement and desired output, you really need larger heads to properly compliment the rest of the engine package. Now, ratiowise (again mathematically speaking) if you went w/the 406 displacement and 195cc heads, you would be in the same situation you are now and the same situation the 302's were with the factory 135cc heads. What displacement are you planning on going with when you stroke the 400? AND, are you going the route of NOS w/the stroked 400 also? Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
zthis Posted September 6, 2007 Author Share Posted September 6, 2007 Kevin Thanks for the post I agree with you 100% (well maybe 95%). The motor is what it is. It had a smaller cam at one point and it liked the new one better. For the rest of this season i'm focused on getting that 10 without changing anything in the motor and once i do the NOS is going back on and i'll start lowering my 10.30 NOS pass. Curtis Quote Link to comment Share on other sites More sharing options...
datsunlover Posted September 6, 2007 Share Posted September 6, 2007 I'm sure you will pick up a little bit switching to an electrical pump, just not having to use engine power to drive the mecanical one... how much I don't know... Same principal as running an electric fan, as oposed to a mecanical. And I've heard of people running a lower oil level than normal, just so it's not in the pan 'dragging' on the crank/rods as it flys around, but I don't know if I'd want to chance it myself. Sorry if I missed it, what are you running for a rear end? I'm just thinking if you don't want to do more major engine work to gain power, could you use the power you HAVE but do more with it by running a higher (numericaly) rear gear? Or would you 'run out' of gears in the transmition to soon? Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted September 6, 2007 Share Posted September 6, 2007 An old trick a guy told me was to use some soft springs on the brake caliper rods to keep the pads from dragging on the rotors... He swore by it... Another thing you may want to try is some headlight covers to reduce drag. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted September 6, 2007 Share Posted September 6, 2007 How about remove the alternator belt and maybe the alternator? Quote Link to comment Share on other sites More sharing options...
zthis Posted September 6, 2007 Author Share Posted September 6, 2007 i'm currently back to 3.55 gears (crossing the line at 6200). I beat my 3.90 (crossing the line at 6800) to pieces early this season. I was running low 11.3s with that gear set but i made a few other small changes when i went to 3.55 (carb spacer and shimmed up the back of the hood 1 inch to release air. I think 3.70 would be the ideal gear. I will be removing the alternator belt. Not sure if i'm going to have time to switch the fuel pump or not. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted September 6, 2007 Share Posted September 6, 2007 Maybe just an alternator cut out switch. Not as 100% as removing the belt, but you can at least ensure a full charge in case you get stuck at the line. Quote Link to comment Share on other sites More sharing options...
zthis Posted September 9, 2007 Author Share Posted September 9, 2007 OH YA GOT MY 10...... 10.998 at 122mph 1.567 60 ft backed up with a 10.927 at 122mph 1.520 60 ft my previous best was actually a 11.070 at 121mph theres what i done... installed electric water pump removed alternator belt removed 90 lbs (NOS system, stereo, wiper motor few other odds and ends quart (or liter as we say in Canada) lower on oil reduced tire pressure to 15 psi tighten chain on front end shallow staged and finally said a small prayer to the Z gods. Thanks to all you guys for the tips NEXT RACE GOAL 9.999 on NOS Curtis Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted September 9, 2007 Share Posted September 9, 2007 Congrats Curtis, Since you did so much at once it is going to be hard to determine what helped th most, but at least you reached your goal. John Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted September 9, 2007 Share Posted September 9, 2007 Congrats!! Quote Link to comment Share on other sites More sharing options...
Bigdeezs Posted September 13, 2007 Share Posted September 13, 2007 I love reading a post with a happy ending! Quote Link to comment Share on other sites More sharing options...
m1noel Posted September 14, 2007 Share Posted September 14, 2007 Congrats Curtis, and nice 60' times. Mike Quote Link to comment Share on other sites More sharing options...
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