I'll probably be swapping in an SR20DET sometime next spring, but wouldn't mind playing with the GA16 for awhile before hand. Anyway, I've got a few ideas that I am interested in just looking at the engine and wanted to see if anyone has any background on any of it.
1st: Does anyone happen to have any data on the intake plenum volume and the runner lengths and diameter on the GA16DE intake manifold from the B14 cars? I was looking at one earlier and the plenum looked a bit larger and the runners a bit wider/shorter, so I was thinking about trying to fabricate a couple of adapter brackets to adapt it onto the B13 GA16DE that I'm using now just to play around. If the volume and runners are sufficiently different it might just be worth it for a little bit of high-end power.
2nd: As I was looking at the throttle linkages on the throttle body it occured how easy it would be to change the location of the TB unlike on some other cars just by replacing the brackets a little. This led me to wonder if anyone has experimented with larger throttle bodies with parabolic tapers to the intake manifold? A parabolic taper would tend to increase intake velocity of the intake charge, and that coupled with a larger TB would also allow the mass of the intake charge to increase as well. A simple 1-2cm plate adapter would be easy enough, and also provide a way to reduce turbulance by moving the greatest source further away from they cylinders and allowing the intake charge to smooth out. I'd think that this would be a fairly effective way of freeing up some power, and would be especially effective on a FI car.
I'll probably be swapping in an SR20DET sometime next spring, but wouldn't mind playing with the GA16 for awhile before hand. Anyway, I've got a few ideas that I am interested in just looking at the engine and wanted to see if anyone has any background on any of it.
1st: Does anyone happen to have any data on the intake plenum volume and the runner lengths and diameter on the GA16DE intake manifold from the B14 cars? I was looking at one earlier and the plenum looked a bit larger and the runners a bit wider/shorter, so I was thinking about trying to fabricate a couple of adapter brackets to adapt it onto the B13 GA16DE that I'm using now just to play around. If the volume and runners are sufficiently different it might just be worth it for a little bit of high-end power.
2nd: As I was looking at the throttle linkages on the throttle body it occured how easy it would be to change the location of the TB unlike on some other cars just by replacing the brackets a little. This led me to wonder if anyone has experimented with larger throttle bodies with parabolic tapers to the intake manifold? A parabolic taper would tend to increase intake velocity of the intake charge, and that coupled with a larger TB would also allow the mass of the intake charge to increase as well. A simple 1-2cm plate adapter would be easy enough, and also provide a way to reduce turbulance by moving the greatest source further away from they cylinders and allowing the intake charge to smooth out. I'd think that this would be a fairly effective way of freeing up some power, and would be especially effective on a FI car.
These sound like great ideas. I cant help with any knowldge of the American delivered intake plenum sizes but if you wnt I can measure the Australian N15 ga16de intake plenums as I have a spare sitting detatched under my house.
RE: Q1, Would increasing the volume of the intake plenum work that much better than extrude honing the existing plenum? Would the gains be worth the cost of the replacement part?
and Q2, you have me confused about which part of the sr20 (assuming that is the throttle body you'd try) has parabolic shapes. Are you talking about engineering a larger throttle body where the whole inside chamber is of a parabolic shape or are you saying that changing the butterfly plate to a parabolic shape would increase the intake charge velocity? Also, would there be any reduction in turbulence induced by the throttle body if you were to polish the butterfly plate?
The throttle body off an Australian N15 Pulsar SSS with an sr20 is supposedly the largest fitting throttle body supplied to this country. Guys over here with the Silvia S14 or S15 200sx(our spec - you have the 240sx) have been swapping their sr20 throttle bodies with those of Pulsars. I can see if I can get any more info on the Pulsar throttle body if you would like. I dont know if its any different to what you get over there.
cheers,
Mark
cheers,
Mark
__________________
Mark.
nth.bris.qld.au - JNN15 ga16de and abandoned upgrade to an Autech SR20 with LSD due to seller losing parts :( Mark Greenmantle Photography
Your observations are correct, the B14 IM is better than the B13. I have compared the B13 IM gasket to the B14 and it is significantly different. I believe the biggest difference is the coolant passage on the head. Also IIRC the bolt pattern is different, not to mention spacing. That said the B14 head is better as well with straighter ports and the B14 cams have a bit more top end than the B13 cams. It is a rather involved swap in terms of putting a B14 head on a B13 car.
The larger TB would help quite a bit, I'm assuming this taper is in the IM itself? can the same effect be achieved (to some degree) by a nice velocity stack on the intake itself? After all both are before the throttle plate correct?
If you need detailed pics. of a B14 cylinder head and IM I have them.
These sound like great ideas. I cant help with any knowldge of the American delivered intake plenum sizes but if you wnt I can measure the Australian N15 ga16de intake plenums as I have a spare sitting detatched under my house.
If you could measure the volume of the plenum itself that would be great. Shouldn't be harder than blocking off the intake runners and filling it with water and then measuring the quantity of water. Never know where a good swap part might be found.
Quote:
RE: Q1, Would increasing the volume of the intake plenum work that much better than extrude honing the existing plenum? Would the gains be worth the cost of the replacement part?
Depending on the increase in volume and runner design it could be a beneficial modification. With an extrude-honed manifold it usually opens the runners enough that they are really only applicable on a forced induction car, but since the displacement and compression of the GA16's from the different years are the same, a lot of times the intake is redesigned in later years to provide additional power to compensate for power lost to emissions changes (head design and intake design typically get better to compensate for emissions controls, for instance the Saturn DOHC engine where in 93 the head was redesigned to replace the power lost from the transition from a tubular to a cast exhaust manifold).\
Quote:
and Q2, you have me confused about which part of the sr20 (assuming that is the throttle body you'd try) has parabolic shapes. Are you talking about engineering a larger throttle body where the whole inside chamber is of a parabolic shape or are you saying that changing the butterfly plate to a parabolic shape would increase the intake charge velocity? Also, would there be any reduction in turbulence induced by the throttle body if you were to polish the butterfly plate?
An SE-R TB might be a good candidate. What I am thinking would be to machine a 2cm spacer to allow a parabolic taper between the new TB and the intake manifold port. Should be a simple design, and the only hard part is machining the taper usually. I've got the formula for designing an ideal parabolic taper at home, but from what my alcahol-soaked brain can recall, it should be 1.5x the diameter, so a 40mm opening should have a taper based on a 60mm diameter curve. Again, I may have the formula wrong, but I can check when I get home.
Quote:
The throttle body off an Australian N15 Pulsar SSS with an sr20 is supposedly the largest fitting throttle body supplied to this country. Guys over here with the Silvia S14 or S15 200sx(our spec - you have the 240sx) have been swapping their sr20 throttle bodies with those of Pulsars. I can see if I can get any more info on the Pulsar throttle body if you would like. I dont know if its any different to what you get over there.
Good info, do you happen to know the throttle plate diameter and the bore diameter at the mouth and outlet?
Your observations are correct, the B14 IM is better than the B13. I have compared the B13 IM gasket to the B14 and it is significantly different. I believe the biggest difference is the coolant passage on the head. Also IIRC the bolt pattern is different, not to mention spacing. That said the B14 head is better as well with straighter ports and the B14 cams have a bit more top end than the B13 cams. It is a rather involved swap in terms of putting a B14 head on a B13 car.
I hadn't even started looking at the head yet, I'll have to get my hands on one one of these days. As far as the intake, that should be pretty easy to do with just an adapter plate. The coolant passage shouldn't be a problem at all. I'll have to see if I can pull an intake from a junker around here one of these days and see how different they are.
Quote:
The larger TB would help quite a bit, I'm assuming this taper is in the IM itself? can the same effect be achieved (to some degree) by a nice velocity stack on the intake itself? After all both are before the throttle plate correct?
A plate to adapt the intake to the TB would probably be the most efficient way, both economically and hp-wise. Should be easy to machine off the car and then just install as a bolt-on swap.
Quote:
If you need detailed pics. of a B14 cylinder head and IM I have them.
If you wouldn't mind, that would be great. If you want, you can email them to forum-admin@domesticracingconcepts.com. (That's a site that I am in the process of modifying to all hell, the site that you currently see there should be transitioned to the new site on the 21st, presuming that I can get past these database issues with MySQL and finally fix the bugs in the dev site).
sc2_ct I'll see what I can find out for you re: volume of TB
and re: sr20de bore from N15 SSS.
cheers
Mark
__________________
Mark.
nth.bris.qld.au - JNN15 ga16de and abandoned upgrade to an Autech SR20 with LSD due to seller losing parts :( Mark Greenmantle Photography
Hey Wes, I got those pictures you sent, those look great. My first impression is what an odd TB mounting design. That was definately not designed for performance. I need to wait for some parts to dry (I'm currently using the hood for a workbench since I've got a lot of exterior and interior work going on right now), but I need to take a look at the TB connection on the 1st design GA's intake manifold. I'm almost thinking that with that design it would be a lot more involved to make an effective intake design. A circular bore into the intake plenum would probably be a much more effective design than that channeled design in the pictures. To do that you'd almost have to fill in that area with layed up welds and then bore it to a propper circular opening and blend it into the plenum (I can't tell with the lighting what happens after the mouth itself, but I would assume that it it flattens out pretty quickly based on the outside dimensions of the upper manifold, so the blending shouldn't be too difficult. It would definately be moving the powerband up pretty high to do that too, so you'd definately want to use FI and a re-worked head. The only part that really worries me though is that I'm not sure how the change in the inlet is going to affect the air distribution across runners 1-4.
Another option would be to design a plate that had the same scale inlet and outlet and the same dimensions, but that would definately require some CAD work to get the correct dimensions and I'm not sure it could be machined efficiently without a CAD-operated mill.
As for the pictures of the head work, that looks pretty good. Is that a 2 or a 3 angle valve job? I think I might bring the head off this car down to the machine shop for a little freshening up and to see how it reacts to some better flow. From what I understand the exhaust flows pretty well, but that the intake is the main weakness on this engine? Do you know of a good source for light-weight replacement valves for the GA16DE by any chance?
Also, since most of the intake work that looks possible is likely to build power higher in the powerband, that begs the question of how capable this engine is of high revving? Do you happen to have the figures on the rod/stroke ratio by any chance? I'd check the book, but it is a few towns away in my other project car (a 13.9 second Saturn lol). If the R:S is decent and the side-loading weren't too bad, it might make sense to try some light valves and stiff springs and try to move that redline up. Does the GA16DE typically have problems with valve or ring float at upper RPMs? Sorry to hit you with so many questions, but I've started getting interested in the GA16DE and am starting to wonder whether there might in fact be a demon in there somewhere. From what I've heard in a couple of other posts, the connecting rods are pretty tough, but the bearing seem to be an achillies (sp??) heel of sorts.
I'm almost thinking of putting off that SR20DET swap in favor of a 5speed swap and playing with this engine for awhile. It may be the red-headed stepchild of Nissan engines, but then again, someone who modifies Saturns probably doesn't fit the norm anyway LOL.
The valves are small and the springs will have float issues at higher RPM's. The valves also have a small shaft diameter so I was reluctant to back cut and unshroud the stockers for fear of weakining them too much. I would say Ferrea would be a good candidate to make a new set of valves.
The weakiness that Bob found was the connecting rod bolts, time will tell how the bearings hold up.
guys, finally found my memory card for my camera so will be taking pics of the australian ga16 parts in the morning.
cheers
Mark
__________________
Mark.
nth.bris.qld.au - JNN15 ga16de and abandoned upgrade to an Autech SR20 with LSD due to seller losing parts :( Mark Greenmantle Photography
I hadn't even started looking at the head yet, I'll have to get my hands on one one of these days. As far as the intake, that should be pretty easy to do with just an adapter plate. The coolant passage shouldn't be a problem at all. I'll have to see if I can pull an intake from a junker around here one of these days and see how different they are.
A plate to adapt the intake to the TB would probably be the most efficient way, both economically and hp-wise. Should be easy to machine off the car and then just install as a bolt-on swap.
If you wouldn't mind, that would be great. If you want, you can email them to forum-admin@domesticracingconcepts.com. (That's a site that I am in the process of modifying to all hell, the site that you currently see there should be transitioned to the new site on the 21st, presuming that I can get past these database issues with MySQL and finally fix the bugs in the dev site).
mate, click here to see where I posted the pics. I have some of the answers there but havent gotten around to finding something I can measure the volume of the intake manifold with. (the missus will kill me if I take her kitchen stuff into the garage.. hehe)
cheers,
Mark
__________________
Mark.
nth.bris.qld.au - JNN15 ga16de and abandoned upgrade to an Autech SR20 with LSD due to seller losing parts :( Mark Greenmantle Photography
I have a 95 200SX SE-R throttle body and I would like to put it on my 92 XE intake. Exactly how would you plenum the intake to make the throttle body fit right.
Hey Wes, I got those pictures you sent, those look great. My first impression is what an odd TB mounting design. That was definately not designed for performance. I need to wait for some parts to dry (I'm currently using the hood for a workbench since I've got a lot of exterior and interior work going on right now), but I need to take a look at the TB connection on the 1st design GA's intake manifold. I'm almost thinking that with that design it would be a lot more involved to make an effective intake design. A circular bore into the intake plenum would probably be a much more effective design than that channeled design in the pictures. To do that you'd almost have to fill in that area with layed up welds and then bore it to a propper circular opening and blend it into the plenum (I can't tell with the lighting what happens after the mouth itself, but I would assume that it it flattens out pretty quickly based on the outside dimensions of the upper manifold, so the blending shouldn't be too difficult. It would definately be moving the powerband up pretty high to do that too, so you'd definately want to use FI and a re-worked head. The only part that really worries me though is that I'm not sure how the change in the inlet is going to affect the air distribution across runners 1-4.
Another option would be to design a plate that had the same scale inlet and outlet and the same dimensions, but that would definately require some CAD work to get the correct dimensions and I'm not sure it could be machined efficiently without a CAD-operated mill.
As for the pictures of the head work, that looks pretty good. Is that a 2 or a 3 angle valve job? I think I might bring the head off this car down to the machine shop for a little freshening up and to see how it reacts to some better flow. From what I understand the exhaust flows pretty well, but that the intake is the main weakness on this engine? Do you know of a good source for light-weight replacement valves for the GA16DE by any chance?
Also, since most of the intake work that looks possible is likely to build power higher in the powerband, that begs the question of how capable this engine is of high revving? Do you happen to have the figures on the rod/stroke ratio by any chance? I'd check the book, but it is a few towns away in my other project car (a 13.9 second Saturn lol). If the R:S is decent and the side-loading weren't too bad, it might make sense to try some light valves and stiff springs and try to move that redline up. Does the GA16DE typically have problems with valve or ring float at upper RPMs? Sorry to hit you with so many questions, but I've started getting interested in the GA16DE and am starting to wonder whether there might in fact be a demon in there somewhere. From what I've heard in a couple of other posts, the connecting rods are pretty tough, but the bearing seem to be an achillies (sp??) heel of sorts.
I'm almost thinking of putting off that SR20DET swap in favor of a 5speed swap and playing with this engine for awhile. It may be the red-headed stepchild of Nissan engines, but then again, someone who modifies Saturns probably doesn't fit the norm anyway LOL.
The rod/stroke ratio for the GA16 is 1.6:1 as far as connecting rods go I came across something very interesting lastnight as I was tearing down a GA16DE.I compared the rods to a set I have from a GA16I.The I rods make the DE rods look weak! The beam on the DE rods was .705" wide ,the I rods were .830". The small end of the DE rods is also alot thinner,in some areas it's less than .090" thick,the I rod is about .125" and seems to be centered much better .The DE rod looks like a twig when sitting next to the I rod.The DE motor I took apart was out of a wrecked Sentra production date 10/91.maybe these early motors have thin rods I don't know.I would like to hear from anyone that has torn down a DE motor and see how thick the rods were in it.After seeing these rods I can't believe they are holding up ,with a set of I rods and some forged pistons the GA16DE should have a pretty tough bottom end.Also I have an old Nissan Motorsports catalog from I think 97 and it shows the same part# for the I and DE rods,the # for the cranks are also the same.Does anyone know the rod lengths of the GA14,15,18,motors?Is there really a GA18 and what country is it from?
Last edited by turbob12 : Sep 14th, 2004 at 05:15 AM.
I've got a 95 200SX SE-R Tb sitting around too. Eyeballing it, the bolts match up with the intake manifold, TPS plugs right in, coolant lines are no prob, and throttle and cruise connections were looking good too. My plan was to take off the intake manifold and port match it to the TB with a dremel - essentially turning that end of the manifold into a velocity stack immediately behind the butterfly...
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