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the sr TB does increase throttle response...i have done the swap in the past...makes a noticeable increase.......one of the few that have done it....:)unfortunately i dont have either the car or the manifold/tb set up any more...been years since i did it....sold it to a member on the forums...hopefully its still in use....lol
but look forward to seeing the euro cam install...and testing....
 

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I did a little more research, and testing on the Pulsar this weekend.
I have come to the conclusion that a SR20 throttle body would not bring any signifficant gain to the HP, and probbably would loose some throttle response. With the stock GA16DE TB on the MPFI manifold I hooked a vacuum gauge in place of the carbon canister, which supplies vacuum from immediatly after the butterfly. At 6,700 RPM climbing a steep hill I have 0 inches of vacuum with the throttle at 7/8- 100% open. This means that the air filter, MAF, and TB are big enough to supply sufficient air under the highest RPMs under high load.
Since I have fixed the back pressure issues on the exhaust and have sufficient flow there, I think the next place of restriction would be the cam/ head/valves. I had almost forgotten about the GA16I NISMO EURO cam, that boasts an aditional 20 HP over the stock GA16I cam. I decided that would be my next step, and have ordered it.
I really want to Dyno this setup again before I do the EURO cam swap, to get some real numbers for both setups, but I probbably will wait till after the EURO cam swap, and get the final results. I just hate to go off how the engine feels, rather than concrete numbers that show the gains/ losses of a particular swap or modification.
bob, wait to do a before and after. with your abilities you'll be able to do the cam swap in 30 mins, another 30 mins for break-in, then do some more runs on the dyno. you can do your before and after in one day :p.
 

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Can't wait to see the writeup on this bob. Looks great, and can't wait to do it to mine.
Keep up the good work, can't wait to see what your pulsar does on the dyno.
 

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Discussion Starter #84
the sr TB does increase throttle response...i have done the swap in the past...makes a noticeable increase.......one of the few that have done it....:)unfortunately i dont have either the car or the manifold/tb set up any more...been years since i did it....sold it to a member on the forums...hopefully its still in use....lol
but look forward to seeing the euro cam install...and testing....
Just to clarify what engine were you swapping the SR20 TB onto? The stock GA16I is TBI, and you would not be able to put a TB from a MPFI engine without the manifold. If you were putting the SR20 TB on a GA16DE that is a whole different story, it has 16 Valves , and 2 cams with different overlap/duration/lift.
As my current setup is now I have no need for any more flow through the TB since the Vacuum drops to 0 Inches before I get it all the way open. Maybe after I do the EURO cam swap I will need it...
 

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Discussion Starter #85
bob, wait to do a before and after. with your abilities you'll be able to do the cam swap in 30 mins, another 30 mins for break-in, then do some more runs on the dyno. you can do your before and after in one day :p.

I would like to do that, I was hoping to talk with the guys at the Dyno, and see if they would let me do 2 runs, and then come back an hour or so later and do two more runs for a small increase of price.
I just don't want to fork out $85 twice.

I really am curious what kind of power I am getting now since I have changed to a GA15, but now have headers, freeflowing exhaust, and working injectors.
I also would like to see what the Euro cam does all by itself.
 

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I would like to do that, I was hoping to talk with the guys at the Dyno, and see if they would let me do 2 runs, and then come back an hour or so later and do two more runs for a small increase of price.
I just don't want to fork out $85 twice.

I really am curious what kind of power I am getting now since I have changed to a GA15, but now have headers, freeflowing exhaust, and working injectors.
I also would like to see what the Euro cam does all by itself.
should be well over that of a GA16i. 100cc's of difference in size due to bore diameter is not going to be that much of a difference in power. if it was due to a difference in stroke, then it would probably be more significant.

as for them letting you do more pulls, unless the want to be dicks, you've been there before. letting you do a couple more pulls an hour later shouldn't be an issue.

just explain to them what you're doing. if they're not busy, i'm sure they'd even go as far as to help you get the cam in right there at the shop. like i said before, it takes no time at all.
 

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Discussion Starter #87
Well, I am a little torn at this point. I would like to Dyno it before and after, but funds right now may not allow even an after Dyno run. My father totaled his car, and I purchased another one this past weekend for him, so I either have to wait for a few months to do the cam swap :( or just swap it and do the Dyno later when money is not so tight.
I really wanted to get the Euro cam in there to see the difference, but at this point I think I will wait till I can do the Before and After Dyno.

BTW the GA15E is still running strong, and consistantly getting 32 MPG in the city. I have yet to take it on a long highway trip to see what I will get for mileage there, but I have high hopes!
Till next time,
Bob
 

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Just to clarify what engine were you swapping the SR20 TB onto? The stock GA16I is TBI, and you would not be able to put a TB from a MPFI engine without the manifold. If you were putting the SR20 TB on a GA16DE that is a whole different story, it has 16 Valves , and 2 cams with different overlap/duration/lift.
As my current setup is now I have no need for any more flow through the TB since the Vacuum drops to 0 Inches before I get it all the way open. Maybe after I do the EURO cam swap I will need it...
oh sorry still use to ga16de motors and sr20de(and sr20dets)...lol
still gettin use to dealing with these older models....but all the same glad she is running strong...and you should be upwards of 38mpg on the highway if you are pulling down 32mpg in the city! that is awesome better than most new cars
i know my 91 E with jdm swapped sr20 and all the bolt ons for it would pull 38mpg on the high way all day long and not even think about it! and my completely stock 92 xe with ga16de got 48mpg on the highway!!!!!blew my mind!(had to make several trips to maryland from ohio for work....true testament to nissan and their engineers!
sorry to hear about your dads car....was nice to get him another one...hopin it was a nissan...lol

just make sure you keep the cam nice and oiled if you arent gonna install it anytime soon!
 

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Discussion Starter #89
Still throwing down 32MPG in the city!
I talked with another dyno this past weekend, and they will do a 3 pull run before and after a swap for $100. They told me that the actual numbers of their dyno might read low, but was the most accurate in town for showing the difference in a swap or Mod in HP. After looking at the stock GA16I camshaft, the stock JDM GA15S camshaft, and NISMO Eurosport cam, I was supprised that I could not see any difference between them, with the possible exception of the NISMO cam very vaguely looks like it might have wider lobes. I wish there were more information on these cams out there like duration, lift, lobe seperation, ect.
I plan to take the pulsar on a 2,000+ mile road trip next week on a vacation, so the Dyno will have to be when I get back.
 

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Discussion Starter #90
Update:
So I had to postpone the 2,000 mile road trip /Vacation because unusal amounts of snow. The last 3 tanks of gas I have run through it (city driving) have been 34MPG.

I also found out the reason for the detonation at higher RPM when the engine was warm. When I was tuning the stock TPS to the new injector setup I noticed that it would almost flood the engine when I opened the throttle, so after much testing and ocilliscope diagnostics I put a 60K Ohm resistor in series with the TPS to attenuate the signal. That was before I resolved the bad injector issue, so 60K Ohms is actually too much, and was causing it to lean out especially under hard acceleration and when it was warmer it would detonate. I have since been trying to narrow it down to a speciffic value that would work for the new working injectors, but for now I am running it with the TPS unplugged. It actually has no throttle lag, and runs even better than with either the stock or modified versions!

My previous thoughts about the TPS being only a subsitute for a accelerator pump, were way wrong. A TPS typically has controll over the duration of the injector pulse, not only when it senses rapid changes in posistion, but during all times when the idle switch is not energised. Along with the signal from the MAF the computer decides how much fuel needs to be injected for an aproximate mixture. Then the O2 sensor does the fine tuning feedback to the computer to give you the best mileage without going lean.

I am learning so much about the way these systems work, I am very glad I decided to tackle this project.
 

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Discussion Starter #92
Update

Project GA16E is still running strong!
Work has been very slow for me the past two months, and money has gotten even more tight. I still have been holding out on the Euro cam swap till I can dyno it fot the before and after, but I am starting to get anxious.
I have chased down a few random phantom bugs that turned out to be loose connections on the CTS, and MAF.
This weekend, since I had some spare time I took the lifter cover off, and did some clean-up and then painted it.
I will be posting some pictures up of the engine bay soon, even though I usually don't care much for how an engine looks, I have to say that I am rather happy how this one looks.
Untill next time,
Bob
 

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nice job! very clean!
 

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you can route the throttle cable underneath the intake manifold to help "clean" up the engine bay a bit.....it is a common "mod" on the ga and sr motors.....
 

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Discussion Starter #96
So, It has been quite some time on this project, and I just wanted to throw out an update.
I finally got too impatient for the extra budget to come in for the Dyno on the euro cam, so I went ahead and swapped it out.
Power band is way smoother, no point does it lag, or peak.
After 5,000 miles of 85% interstate driving it has a new average of 39MPG(was 43MPG average before)

There was still one problem with the stock computer that annoyed me where it would buck when you opened the throttle a little, though it was very good everywhere else I decided to swap in the GA16DE computer and harness and installed it to the car. Now it has even more pep, and redlines at 7,000 RPM. With the Euro cam, GA16DE intake manifold and Headers it really comes alive, and I am worried about my brakes being insufficient :rolleyes:

I am sure many of you are thinking after all I have done I should have just put a GA16DE in the car, and you may be right but all in all if I were to do this mod to my 89 Sentra I still would do it this way, because I can keep most of the stock parts, just swap out the Intake manifold and computer.

More info to come
Bob
 

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Nice work !! I thought I had read some where that the GA16i and GA16DE use the same engine block only the manifold and heads are different?? Would this swap be easier if you could swap the head and manifold from the DE engine??
 

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Discussion Starter #98
Nice work !! I thought I had read some where that the GA16i and GA16DE use the same engine block only the manifold and heads are different?? Would this swap be easier if you could swap the head and manifold from the DE engine??
I remember reading that too, and was thinking the same thing. I do remember hearing that the rods and pistons were different between them. I know that the DE head uses a different timing chain cover and timing components. I think other than that I would be able to do a head and manifold and computer swap to make a GA16I into a GA16DE
It would be good to get conformation about the pistons and rods.
 

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Pics no worky :(

I'm kinda' getting interested in this. I had my mind set turbo with Yamaha RX1 carbs, but I know that with carbs my MPG will suffer a good bit being tuned for turbo (i.e. stays rich all the time).
 

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Discussion Starter #100
Long story short the Pulsar with GA16E is running great! But now is waaaaay on the back burner! I got married in June 2011 and my son was born April 2012. I now drive my 1989 sentra (better family car) and it might be a long while before I do much more to this project. I also now live in a townhome with covenents and HOA and nowhere to work on cars so I am very limmited to what I can do :(
GA16DE and GA16I uses the same block as far as I know. just a different head, pistons rods and timing junk. If I had time LOL I would swap a GA16DE head onto my sentra and continue the project with my sentra.
 
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