Rockfrog Posted October 10, 2014 Share Posted October 10, 2014 So, just made the first run in the Ratmanche .... Seems a little down on top end (maybe just in my head, haven't driven her since june). Hold steady in 5th but not a lot of pull available (probably due to 3.07s and 235s). Anyway, to the meat, I was thinking about something I read about adding the 99 intake to earlier 4.0s and it was about a reduction in intake velocity causing a top end power loss. Any thoughts on this? I do have a 2.5L throttle body available which is the same size bore as the Renix TB (at least to my eyeball Guage they appear so) ... Any merits to the theory? I was also thinking I might swap the 2.5s IAC housing onto the stock 94 TB in an attempt to reduce the idle (hot idle is back up to 1200 or so rpm, have to wait til Wednesday to see where cold idle is again). Only other issue on the first 250km run was a slight stumble on deceleration only. Otherwise she runs smooth as a babies bottom. Link to comment Share on other sites More sharing options...
ParadiseMJ Posted October 10, 2014 Share Posted October 10, 2014 I am also plagued with 3.07's. It is somewhat sluggish in OD (aka 5th) unless I'm going 70+ on the freeway/highway. When I had a 5 speed, 5th gear was pretty much useless (unless I was going 70+ on the freeway/highway). My own experience tells me that 3.07's just suck in general. You're not going to get alot of power, ever, in any gear over 3rd. Link to comment Share on other sites More sharing options...
Rockfrog Posted October 10, 2014 Author Share Posted October 10, 2014 I have a 3.55 27 spline 8.25 to throw in eventually... Guess it's just culture shock coming from the XJ on 35s and 4.56s Update... Way more power in 1st through 4th even some in 5th once I sorted out the IAC and a few vacuum leak issues. Link to comment Share on other sites More sharing options...
Rockfrog Posted October 18, 2014 Author Share Posted October 18, 2014 I've like to revisit this one from a different angle ... Would there be any benefit ... from a fuel economy perspective ... to dropping from the 58mm bore of the 4.0 HO throttle body down to the 52mm of a 2.5 throttle body? I mean it was the stock Renix bore anyway. Just thinking out loud really more than anything. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 I've like to revisit this one from a different angle ... Would there be any benefit ... from a fuel economy perspective ... to dropping from the 58mm bore of the 4.0 HO throttle body down to the 52mm of a 2.5 throttle body? I mean it was the stock Renix bore anyway. Just thinking out loud really more than anything. Nah. Link to comment Share on other sites More sharing options...
Rockfrog Posted October 18, 2014 Author Share Posted October 18, 2014 You be makin me sad mister. I just remember reading about a drop in take velocity being the main issue with using a 99 intake. Engine is running great, except for a troublesome exhaust leak (crappy exhaust gasket, possible warped manifold have a spare good one). Last run was 16.8 mpg with a really leaky exhaust (mating flange had loosened off and the section past the cross member was cobbled) and a large vacuum leak ... so actually pretty good considering. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 18, 2014 Share Posted October 18, 2014 I just remember reading about a drop in take velocity being the main issue with using a 99 intake. I've never heard of that one. Been running the 99 intake for years and did have it dynoed before and after. It made some pretty decent numbers. Even got a slight improvement in fuel economy. http://www.jeepstrokers.com/forum/viewtopic.php?f=5&t=387 Link to comment Share on other sites More sharing options...
Rockfrog Posted October 18, 2014 Author Share Posted October 18, 2014 Cool, so I'm probably just over thinking it is all then. Going to grab some more exhaust donuts later today and seal the flange connection, not impressed with the "wire mesh" seals I keep getting. Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 18, 2014 Share Posted October 18, 2014 Just my opinion- Unless you are going to port and polish your head, remap, tune your injectors, upgrade your exhaust, cam and cam timing, choose intake and polish runners.......etc........ IOWs you may well increase flow at the TB only to choke it up at the head or exhaust.......to lean it out if you do not alter fuel........then what is the point? Further- I'd rather look for grunt- Torque. Who runs the 4.0s or 2.5s at 5000rpm anyway? Link to comment Share on other sites More sharing options...
Rockfrog Posted October 18, 2014 Author Share Posted October 18, 2014 Well it made more sense than using an 88 manifold on a 92 head. The 88 head was toast, not use able. I had a 99 intake, 92 head and various throttle bodies on hand ... So I made due. I have a boat load of 92 up parts, no 90 down. This wasn't a let get power project, it was a get my arse to work project. I have an XJ for the other stuff. I'm just looking at making the best of what I have at the moment. She has plenty of grunt, and rarely sees over 3000rpm if ever. Upside is now most engine parts are more readily available. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 Just my opinion- Unless you are going to port and polish your head, remap, tune your injectors, upgrade your exhaust, cam and cam timing, choose intake and polish runners.......etc........ IOWs you may well increase flow at the TB only to choke it up at the head or exhaust.......to lean it out if you do not alter fuel........then what is the point? Further- I'd rather look for grunt- Torque. Who runs the 4.0s or 2.5s at 5000rpm anyway? The HO used a 58mm TB on a stock engine. Same size valves, cam, displacement etc........... Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 18, 2014 Share Posted October 18, 2014 The HO used a 58mm TB on a stock engine. Same size valves, cam, displacement etc........... Yep, that's correct. Another Renix advantage is that with an HO you'll never experience the joys of dealing with 35 overly-sensitive obsolete sensors that all interact with each other and a poorly engineered leaky vacuum system. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 The HO used a 58mm TB on a stock engine. Same size valves, cam, displacement etc........... Yep, that's correct. Another Renix advantage is that with an HO you'll never experience the joys of dealing with 35 overly-sensitive obsolete sensors that all interact with each other and a poorly engineered leaky vacuum system. Now we're talking. Let the fun begin!! Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 18, 2014 Share Posted October 18, 2014 The HO used a 58mm TB on a stock engine. Same size valves, cam, displacement etc........... Yep, that's correct. Another Renix advantage is that with an HO you'll never experience the joys of dealing with 35 overly-sensitive obsolete sensors that all interact with each other and a poorly engineered leaky vacuum system. Now we're talking. Let the fun begin!! I'll take a pass and let all you masochists enjoy. :rotfl2: Link to comment Share on other sites More sharing options...
Rockfrog Posted October 18, 2014 Author Share Posted October 18, 2014 I minimized the whole vacuum mess up and a couple associated solenoids and valves. Don't have A/C so she's pretty much down to bare bones. I find both my Renix, and my 00 HO about equal to work on ... Just a different tool for each (scanner for the 00, and a voltmeter for the Renix). At the end of the day, it's just a 4.0 ... Easy peasy. Just need to tweak her here and there. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 18, 2014 Share Posted October 18, 2014 I minimized the whole vacuum mess up and a couple associated solenoids and valves. Don't have A/C so she's pretty much down to bare bones. I find both my Renix, and my 00 HO about equal to work on ... Just a different tool for each (scanner for the 00, and a voltmeter for the Renix). At the end of the day, it's just a 4.0 ... Easy peasy. Just need to tweak her here and there. Yup. Link to comment Share on other sites More sharing options...
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