Ok, just spent the day at JWT's dyno experimenting with a bunch of things on the old DE.
For those of you too new to the SR20 scene, its my my teal green 200SX, SCC's Project 200SX SE-R. For many years it was one of the most powerful NA SR's until Andri's latests big bore developments. As a recap, this is a fairly mild by todays standards motor, one easily and cheaply reproduceable by anyone. It has 300ZX pistons, mildly ported low port DPR head with modifed quench (which I now think is superflurous), C3 cams, JWT ECU, Place Racing cold air intake, Maxima MAF, extrude hone intake manifold and a 64mm thottle body. Nothing exceedingly trick here.
What we did was to add a 20V exhaust manifold and a 3" exhaust with a magnaflow 3" cat, submuffler and race muffler. We also expermented with ECU programing and cam timing. We found the right way to go with the programing and cam timing but had to call it quits because of fears of pissing off the neighboors.
First off, the cork in the DE's output is not the intake manifold as I have speculated for years (and what my software and book calculations tells me) but the exhaust! It seems like a well modded SR with cams of a lot of overlap likes a BIG exhaust. 2.5" lost 6 hp over uncorked! 3" lost nothing though the cat! The exhaust manifold is a major restriction as well. We tried the 20V manifold because it has a 3" collector and although a collector this big is against conventional wisdom, we figured that the engineers at Nissan are no dummys. This is going to hugely impact header design!
Next SR's like a lot of overlap and tight lobe centers. Going off my experince at TRD where we found that simular motors like a lobe center as tight as 100 degrees, we found much power and torque here, in fact you run out of piston to valve clearance before you run out of power increse. Most people have been leaving their lobe centers at around 117 basied on my prior testing a long time ago on S3's. Note that this only works if you have low backpressure, big induction and big cams like C3's, C4's etc.
Finaly with a lot of overlap, things that I found previously that made no difference like big TB's, and big MAF's start to make a difference. Its all about overlap scavanging and since the delta P's are low, you need free flow. Its sort of all against the conventional wisdom accumlated so far.
The results are pretty amazing. The previous non cherry picked power was a decent 172 hp. Today we got an amazing 188whp. When comparing the power to Chris Allen AKA Shaggy's VE, perhaps the current VE power record holder, the DE is making more power from 4300 rpm, as much as 17 more hp to 6700 where shaggys power passes to peak at about 11 more hp in a tiny sharp peak. Amazingly the DE has way more useable power under the curve! The powerband is broad and flat accross the top from 6000-8000 where Shaggy's VE is a sharp point, like a B series Honda. This meaty useable power.
This is with conservative 91 octane friendly tuning. We set the mixture at about 12:7-12:8:1 when SR's usualy make the most power at a crackly 13.2-13.3:1. We got a couple more hp when leaning it out but backed out because we wanted a margin of safety with 11:1 and 91 octane.
Shaggys VE makes better power below 4300 rpm, as much as 11 more at around 3300 rpm due to the low RPM lobeand 9 more at 2000 rpm, but you don't RACE at this low of an RPM!
We probably have enough piston to valve clearance to advance the intake cam 2-3 degrees more which should yield over 190 whp and an even broader powerband. We can also screw around with exhaust cam timing (SR's are pretty insensitive to exhaust timing but I think we can reduce overlap here and improve idle) We also have yet to do timing and mixture sweeps to see if the program needs to be changed with the changes in cam timing. I'll report significant progress here.
We will also test a new JWT cam, a mechancial cam with more duration and lift than any SR cam on the market so far. In some intial testing on a Grand Am Sentra, these cams were worth 20 MORE hp than C3's on a milder than mine (rules mandate) motor! The only issue is we won't have enough piston to valve clearance to optimize the cam timing with this combo.
I will also test a short runner big plenum, manifold with a 70mm TB which will be avalible for sale if it works on this motor. I am pretty enthusiastic. I think it might be posible to get well over 200 whp out of a plain old DE without spending extreme amounts of money and with exotica like stroker cranks, sleeved blocks, crazy cylinder heads, suicide tuned dyno queen timing and fuel curves, etc.
Next I will attempt to extract more than 180 whp on a full bolt on DE with a stock head and bottom end. It will be cams, springs, pulleys, CAI, intake manifold, 70mm throttle, Hotshot header, ECU, 3' exhaust. This will be as easy and cheap alternative to a VE.
I'll keep everyone posted.
Mike
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There can only be one Icy Hot Stunta, Don't Hate.
That is awesome tweaking! And to think that you had to defy conventional logic and your previous test data to get these results. Hope you see over 200 whp and I wanna see adyno chart on that sucker, that is if it doesn;t appear in SCC again...
Did you ever install that O2 induction IM on that car or only on your B13?
That is awesome tweaking! And to think that you had to defy conventional logic and your previous test data to get these results. Hope you see over 200 whp and I wanna see adyno chart on that sucker, that is if it doesn;t appear in SCC again...
Did you ever install that O2 induction IM on that car or only on your B13?
Well I am going to JWT tomarrow to work on it somemore. I expect over 190 hp tomarrow and over 200 in the next couple of weeks. I am going to test another short runner manifold but not a O2 induction.
Mike
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There can only be one Icy Hot Stunta, Don't Hate.
Sorry to intrude, I notice that JWT's new SR20 exhaust manifold is recommended with a 3" exhaust. I can't help but think it was inspired by mikes work here. Can the same philosophy used with the SR20 here be use d with a GA16 and the SR20/16VE's. Can an exhaust manifold be designed for the GA16DE engine to use a 2.25 or even 2.5 " exhaust pipe? Or do the head designs restrict that ability? Or maybe no one is willing to investigate the matter?
Further more, can the same principles be used on the VE engines (3" exhaust etc.).
Sorry to intrude, I notice that JWT's new SR20 exhaust manifold is recommended with a 3" exhaust. I can't help but think it was inspired by mikes work here. Can the same philosophy used with the SR20 here be used with a GA16 and the SR20/16VE's?
Yes it could. Various types of mods that work well on the SR20 also help the GA16 to become more responsive and make power also. It really helps to have access to a dyno to chart the gains and losses when experimenting.
Quote:
Originally Posted by shift_of_legend
Further more, can the same principles be used on the VE engines (3" exhaust etc.).
Yes it can. And thanks to Mike's wonderful research and testing, HotShot was persuaded to make a new header (Gen 6) with the same attributes. Works on the DE and VE motors and has a much larger collector for more power overall.
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96 SE-R: SR20VE - bolt ons
97 SE-R: SR20DET 54C - on hold - need $$$
03 Altima SE V6: PR CAI/SS grill/alarm & remote start/100 sf Stinger Roadkill/
19's (need tires)/stereo going in next
Damn! So what are you 1/4 times? Hey can you PM me on some pointers on going All Motor, some parts like cams and ETC. Once you get the 180 whp on the DE let me know!!!
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