misfitmechanic Posted March 29, 2016 Share Posted March 29, 2016 Ive been doing some reading lately on doing a 99+ intake swap on a earlier 4.0 H.O. and was wondering if its a swap worth doing. Ive got a new header to install and it would make sense to upgrade the intake too. The engine in my Comanche is out of a 91 xj so I would have to find a intake ( duh ), power steering pulley and power steering bracket off a 96 and newer xj. Ive read that the 99+ 4.0 engines make there peak torque output at almost 1000rpm less than the earlier 4.0 H.O and would hopefully compliment the upgraded cam that's already in the engine. Thanks for any info or opinions.Earl Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 30, 2016 Share Posted March 30, 2016 Is 12HP worth it? http://www.jeepstrokers.com/forum/viewtopic.php?f=5&t=387 Link to comment Share on other sites More sharing options...
misfitmechanic Posted March 30, 2016 Author Share Posted March 30, 2016 12hp isn't a big gain, I was more hoping on " shifting" the peak torque output into a rpm range that I spend more time in. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 30, 2016 Share Posted March 30, 2016 Don't do it then. :P Link to comment Share on other sites More sharing options...
misfitmechanic Posted March 30, 2016 Author Share Posted March 30, 2016 What does the purple line on your chart represent? AFR? I wish the torque curve on your first graph with the intake started at a earlier rpm. From the reading ive done 99+ engine torque peak is around 2800, while a 91 to 95 H.O torque peak is closer to 3800rpm. If possible id love to shift my peak torque to 2800rpm. Link to comment Share on other sites More sharing options...
johnj92131 Posted March 30, 2016 Share Posted March 30, 2016 What does the purple line on your chart represent? AFR? I wish the torque curve on your first graph with the intake started at a earlier rpm. From the reading ive done 99+ engine torque peak is around 2800, while a 91 to 95 H.O torque peak is closer to 3800rpm. If possible id love to shift my peak torque to 2800rpm. Have you looked at the Renix engine torque curve? As I recall it shows peak torque at a much lower rpm Link to comment Share on other sites More sharing options...
misfitmechanic Posted March 30, 2016 Author Share Posted March 30, 2016 This is a web site that I've got some of my ideas from. http://www.cleggengine.com/downloads/specs/JEEP_4.0_PERFORMANCE_SPECS.pdf Link to comment Share on other sites More sharing options...
teamsmith Posted March 30, 2016 Share Posted March 30, 2016 Ive been doing some reading lately on doing a 99+ intake swap on a earlier 4.0 H.O. and was wondering if its a swap worth doing. Ive got a new header to install and it would make sense to upgrade the intake too. The engine in my Comanche is out of a 91 xj so I would have to find a intake ( duh ), power steering pulley and power steering bracket off a 96 and newer xj. Ive read that the 99+ 4.0 engines make there peak torque output at almost 1000rpm less than the earlier 4.0 H.O and would hopefully compliment the upgraded cam that's already in the engine. Thanks for any info or opinions. Earl I've got a 99 intake sitting in my garage that I'll sell you for cheap. I'm not sure what the going rate is but I can send you pictures. Link to comment Share on other sites More sharing options...
benjy_26 Posted March 30, 2016 Share Posted March 30, 2016 12HP out of one mod isn't a lot? Lol I must have MUCH lower expectations then. Link to comment Share on other sites More sharing options...
misfitmechanic Posted March 30, 2016 Author Share Posted March 30, 2016 Well it's a lot better than a kick in the arse Link to comment Share on other sites More sharing options...
misfitmechanic Posted March 30, 2016 Author Share Posted March 30, 2016 Earl I've got a 99 intake sitting in my garage that I'll sell you for cheap. I'm not sure what the going rate is but I can send you pictures. I live in Ontario Canada so I doubt it would be a cost effective option. Thanks for the offer though Link to comment Share on other sites More sharing options...
schardein Posted March 30, 2016 Share Posted March 30, 2016 I think that the small HP gain, in addition to the much easier belt adjustment of the newer P/S pump setup makes it a worthwhile upgrade. At least at "pick-a-part" prices. Also makes sense if you are replacing a cracked exhaust manifold. If you are doing one, do the other at the same time. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 30, 2016 Share Posted March 30, 2016 Interesting reading: http://mallcrawlin.com/forum/showthread.php?6355-4-0L-99-intake-manifold-swap-with-REAL-DYNO-NUMBERS! Link to comment Share on other sites More sharing options...
Rockfrog Posted March 30, 2016 Share Posted March 30, 2016 I've been running one for the last year or two (time flies). Yeah, it made a difference, especially to a tired old renix 4.0 I used a 92 head, 99+ intake manifold, 94 fuel rail and Volvo 746 injectors, a 94 4.0 throttle body, 94 exhaust manifold, and 96 power steering pump. Think that covers most of it. Even with literally shaveably polished cylinder walls, and a noticeable oil burn at cold start, yeah she's tired, I can now spin my 32" ish JK take offs (255/75r17) at will with 3.07 gearing in first. Something I couldn't do with the stock head and intake/exhaust on 235/75r15's before hand. About the only thing I'd change (beside rehoning the damn motor - sudden onset time constraints canned that plan) would be a smaller throttle body actually ... In fact I'm going to trial a 2.5L Throttle body shortly. With the Renix values plugged into a Throttle Body size calculation and a power TQ) peak at 3400 (something I have yet to go past) ... I need a measly 46mm throttle body for full range power. The 58mm stock 4.0L TB pushes the curve further out the line and is actually something I have noticed on the highway, a slight lag below 1800rpm in higher gears where the motor works harder and the TB is open more. I'm going to try swapping a 2.5L Throttle body on for S&G's to see what happens with a 52mm TB in place. If it works, great, if not, swapping back is easy as pie. Been curious about it for sometime actually, might as well scratch that itch. There is a diminishing return on TB size, and with the larger volume of the later intake plenum (IIRC it 4300cc vs 2600cc volume) there is some food for thought there. The GM TPS swap started this way as well, and works like a hot damn for 1/4 the price. Who's to know if we don't at least try. But I am quite happy with the results of the head/manifolds swap as is. Link to comment Share on other sites More sharing options...
Jeepman Posted March 30, 2016 Share Posted March 30, 2016 EarlI've got a 99 intake sitting in my garage that I'll sell you for cheap. I'm not sure what the going rate is but I can send you pictures. I live in Ontario Canada so I doubt it would be a cost effective option. Thanks for the offer though I have a few of these Newer intakes in my Shop... I am in Stoney Creek ON Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 30, 2016 Share Posted March 30, 2016 I've been running one for the last year or two (time flies). Yeah, it made a difference, especially to a tired old renix 4.0 I used a 92 head, 99+ intake manifold, 94 fuel rail and Volvo 746 injectors, a 94 4.0 throttle body, 94 exhaust manifold, and 96 power steering pump. Think that covers most of it. Even with literally shaveably polished cylinder walls, and a noticeable oil burn at cold start, yeah she's tired, I can now spin my 32" ish JK take offs (255/75r17) at will with 3.07 gearing in first. Something I couldn't do with the stock head and intake/exhaust on 235/75r15's before hand. About the only thing I'd change (beside rehoning the damn motor - sudden onset time constraints canned that plan) would be a smaller throttle body actually ... In fact I'm going to trial a 2.5L Throttle body shortly. With the Renix values plugged into a Throttle Body size calculation and a power TQ) peak at 3400 (something I have yet to go past) ... I need a measly 46mm throttle body for full range power. The 58mm stock 4.0L TB pushes the curve further out the line and is actually something I have noticed on the highway, a slight lag below 1800rpm in higher gears where the motor works harder and the TB is open more. I'm going to try swapping a 2.5L Throttle body on for S&G's to see what happens with a 52mm TB in place. If it works, great, if not, swapping back is easy as pie. Been curious about it for sometime actually, might as well scratch that itch. There is a diminishing return on TB size, and with the larger volume of the later intake plenum (IIRC it 4300cc vs 2600cc volume) there is some food for thought there. The GM TPS swap started this way as well, and works like a hot damn for 1/4 the price. Who's to know if we don't at least try. But I am quite happy with the results of the head/manifolds swap as is. A motor is happiest when the suck and blow are open enough to compliment each other. Sounds like you have good suckage maximus getting strangled by exhaustus minimus. I good header like a Borla, and 2.5" pipe all the way out would balance it out nicely me thinks. Of course, you have to go by what the dyno says, and I don't mean the unreliable butt dyno. Link to comment Share on other sites More sharing options...
Rockfrog Posted March 30, 2016 Share Posted March 30, 2016 The exhaust is a "no crush" stock down pipe to a later model 2.5" from the trans crossover to the tail. Anyway, getting off track, can't hurt but to try in any event. Link to comment Share on other sites More sharing options...
misfitmechanic Posted March 31, 2016 Author Share Posted March 31, 2016 Jeepman, I think I have a intake lined up. If it dosent pan out I'll get in touch with you. I think I'm gonna track everything down for the intake swap first then install everything when I do the header. Link to comment Share on other sites More sharing options...
MiNi Beast Posted February 18, 2022 Share Posted February 18, 2022 Fixin to swap a 99 intake on myself, looking for details before I go ahead and tear things apart. Be also replacing power steering system as well for a tapped hydo assit setup. Never go wrong with any extra ponies me thinks. Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted February 18, 2022 Share Posted February 18, 2022 26 minutes ago, MiNi Beast said: Never go wrong with any extra ponies me thinks. You are CLEARLY not married to an "equine professional". Link to comment Share on other sites More sharing options...
75sv1 Posted February 18, 2022 Share Posted February 18, 2022 I didn't read the whole thread on 12 HP. I remember Hornbrod post a Dyno graph on a Stroker motor with 12 hp increase with a 99+ intake manifold. I've also read the Jordace88 thread. He was on NAXJA for a few months. Posted a 27 hp increase. But if you read the thread, he did a PSI increase to the fuel pump. I'll also note, there is a thread on NAXJA by Bajabronco with his dyno results. Later he upgraded to an adjustable fuel pressure and added 12 hp. OK blah, blah, blah. I have swapped out to 99+ intakes on two '98 XJs. One was mostly stock. The other some improvements. Bored TB 60mm and 62mm, Doug Thorley header, 2.5 exhaust, Ford and then Bosch 12 hole injectors. Some improvements. I will note that I am able to take some inclines better. That can also be done with regrearing. Now if you want to argue about dyno results and butt dyno, I will say for all the dynos the company I work for has, they still do road testing. Now, as to shifting the rmp, torque etc. I say you need to look at the cam specs. The latter ones have less lift and are a split lift cam. Presently, I have mostly assembled a stroker with parts from Bishop Buel racing. Also, I am gearing up to do a mini-stroker, 232 crank. I am looking to get Schneider cams to grind some cams on stock 99+ camshafts. Also, looking to possibly make some dual row roller cams for the 99+ motors. I am also doing Chevy valves with 30 degree intake valve seats. Link to comment Share on other sites More sharing options...
Limeyjeeper Posted February 18, 2022 Share Posted February 18, 2022 This will tell you all you need to know about HP increases with intakes. Pretty interesting. Link to comment Share on other sites More sharing options...
75sv1 Posted February 18, 2022 Share Posted February 18, 2022 Nice video. A lot of info. Still, it is a 4.6 stroker, and highly tuned from there. I will say, I did do the TB blade thinning on my 2000 XJ, stock motor. It seems to help a bit on inclines. I didn't have to downshift to 3rd as much as before. I will say, that I did not get as perceived as much as my '98. I am expecting its the exhaust ports. Could be other stuff. I am running an aftermarket JBA 2000+ ceramic coated header on it. I'd say, I didn't notice any real gain from that. Again, I guess the exhaust ports. I wish they showed their exhuast port a bit more. They go with an O shaped. The 87-99 is a D port. The 2000-2006 is a square port. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted February 20, 2022 Share Posted February 20, 2022 On 2/17/2022 at 6:59 PM, MiNi Beast said: Fixin to swap a 99 intake on myself, looking for details before I go ahead and tear things apart. Be also replacing power steering system as well for a tapped hydo assit setup. Never go wrong with any extra ponies me thinks. If your putting one on a pre 96 engine, grab the pulley bracket and tensioner setup from the 96 and later. You’ll need that to tension the belt since the PS pump will now be stationary on the new intake. Link to comment Share on other sites More sharing options...
75sv1 Posted February 24, 2022 Share Posted February 24, 2022 I remember a write up about swapping on a 99+ intake to 87-95 motors. I think you need to space the PS pump forward a bit. Link to comment Share on other sites More sharing options...
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