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JBrady

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    1999 LS400

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  1. Steve, thanks for the post. My 99 LS400 just acted up tonight. Check engine light, VSC off warning, drove ok for about 3 minutes then leaving a stop light the throttle had no response. Luckily the 98-00s still have a throttle cable and will crack the throttle open at about 3/4 throttle so I was able to limp out of traffic. Did a restart and the same warnings but the throttle was working again. Pulled the code, P1128 and just now pulled up this post in response.
  2. As of today the second link still works!!! Didnt try the first link. Thanks for posting!
  3. Ok, most of the above comments are very good advice. Let me make some small changes and additions that may be of interest to many. The 1st generation 1UZFE engine from 1990-1994 in the LS400 was 10.0-1 compression non-interference and rated 250hp/260tq. These engine are OVERRATED on power. Based on multiple chassis dyno numbers I rate the 1st gen motors at 230hp/240tq. Now, Lexus changed the power rating for the LS400 in 1995 but did NOT change it for the SC400 until 1996. The new engine in the LS400 in 1995 has 10.4-1 compression and IS an interference engine. It also has slighty more timing on the exhaust camshaft and has dual tube exhaust manifolds vs. the single tube design. These engine are correctly rated at 260hp/270tq. Note that the 1995 LS400 is SIGNIFICANTLY quicker than the 1990-1994. A full second 0-60 and 1/4 mile. The mystery is why the SC400 did not get the higher rating until 1996? I am not certain but the SC400s NEVER got the dual tube exhaust manifolds. Maybe rating the 1995 SC400 at 250hp/260tq was now correct with the other changes. Maybe Lexus used up there 1st gen stock of engines on the 1995 SC400, hard to know. The SC400 and LS400 share engines except for exhaust manifolds and oil pans. Personally I would not have a problem using the 2nd gen 1UZFE in an earlier car in fact IMO it is desireable. It would be the same as rebuilding with slightly more compression and better exhaust camshafts. This is not too much for the stock ECU to compensate for. You will need to change manifolds and oil pans between the two engines (LS vs SC). Would also be a great time to add headers.
  4. Well, when I make a post on a public forum I open the subject up to comment and discussion. What does concern me is when someone makes a statement not based on fact and thereby cluttering and confusing the discussion. As a long time Lextreme member/mod I do not recognized your above reference. I did post above regarding SRQ400s 99 SC400 with headers, dual 2.25s, no x or y pipe and stock mufflers reporting very strong low end power... is that maybe what you are thinking about? If you are certain about the other post please provide a link as I must have missed it. Regarding your own experience, did you ever TRY 2.25" pipes as a comparision or are you just guessing that they would reduce your power? You may recall jp430 at CL installing headers on his supercharged GS430 and gaining as much as 43rwhp through the STOCK 1.96" pipes. There may well be another 20rwhp in 2.25" pipes but after that I do not think the gains would be dramatic if at all going to 2.50 or larger. If you are familiar with David Vizard, he writes technical exhaust papers, was involved in the design of the Dynomax Super Turbo muffler (probably the most successful muffler produced) and was involved in the flow testing and subsequent power rating listed for many of the Dynomax mufflers. Check these links quoting Vizard: http://www.houston-f-body.org/tech/exhaust/exhaust.htm http://www.houston-f-body.org/tech/exhaust/exh4.jpg The second link shows a chart that basically indicates at 2.2 CFM flow per horsepower produced there is no significant gains to be made by adding capacity. You can argue other details but going with this you can then check out the dynomax website to compare their mufflers flow capacity and power supported. Go here: http://www.dynomax.com/documents/ultrafloss_specs.pdf look at muffler part numbers: 17291, 17292 and 17293 These 3 are the same size EXCEPT pipe size. Power supported based on their list and above Vizard info is: 2.00" = 364hp 2.25" = 455hp 2.50" = 544hp Now, honestly I am suspect of these numbers BUT it is worth noting the twin turbo Pontiac outlined in Engine Masters that made an outrageous 2800+hp (two thousand eight hundred) had only 2.50 primary collectors. So, again, when I suggest using the SMALLEST pipe that supports you needs I say so with a reason.
  5. Actually, I make the 2 into 1 nozzle and merge collectors between 20 and 30 degrees total merge angle. I assume you are looking at the Borla 40670 with dual 2.25 and single 3.00. http://www.borla.com/products/product_mult...rbo+XL+Mufflers I personally would not recommend a 3.00 center pipe. 3.00 will support huge power and is way larger than needed on a N/A Lexus running stock camshafts. You are also looking at substantial weight, questionable allowable space and over $500 for just those 2 parts. I have shipped 2 sets of the nozzle collectors. Once set to be used on a 93 SC400 running the SS headers. He wanted to go back to 2.00 into a 2.50 center after trying dual 2.50 into 3.00 and lost low end torque. http://lextreme.com/forums/showthread.php?t=4388 The other is trying the 2.25 into 2.50 pipes after trying dual 2.25 merge collector X pipe on his 1998 SC400 (vvti model, 290hp) and also loosing low end power. Here is a link showing his design: http://www.performance928.com/cgi-bin/page...ass_parent=1128 Notice both are nicely formed designs. The problem is TOO much volume for the needs of our small 4.0 liter little cam engines. My nozzle design should restore the lost low end power and still provide sufficient high rpm flow for max power. One more interesting note. Another individual installed the headers with dual 2.25 pipes and stock rear mufflers and NO crossover and his impression was dramatic improvement in low end AND top end power. So, while crossovers are good for virtually all systems they must still be designed correctly to get the desired results.
  6. Well, since the traction control is dynamic it could be malfuntioning and may be open with the engine off and mostly closed with it running. Cats need visual inspection or confirmed pressure test. Adjusting the valves is the valve lash and is done under the valve covers. Buildup occurs on the back of the valve face and the stem INSIDE the port area and would not be visable without removing the intake manifold or using a very small camera looking in through a removed injector hole. As far as your dealership acting fed up with your car... hard to respond there... I would ask the service manager what the car should accelerate to 60mph in (apx 100kph). If he doesn't know show him a copy of a published time easily found on the internet. Once the 8.0 to 8.5 second number is agreed ask him if nearly double that sounds healthy? If no help I would seek competent outside of dealership help.
  7. Replace the middle mufflers with perforated core straight through resonators from a quality provider such as Dynomax, Magnaflow or Borla. Heck, just remove them and run 2.00" pipe in there place. If that is louder than desired simply see first sentence. Now, if you want more POWER... headers, complete system, nozzle collector.
  8. With the 6 speed they are cutting 5.9s My 99 seems like a fast example as I consistently cut 5.9s on my UPDATED G-Tech Pro Competition. The original software for the GTech was MUCH more optimistic recording as good as 5.2s at the track when I ran the 14.2s in the 1/4. FYI, the GTech showed 13.8 @ 104 on both 14.2 @ 99 passes. On the street I would normally run 5.4-5.7 on the old software. The new software has me 5.9-6.0. The new software was engineered to be very close to actual 1/4 times. Only the Competition and newer models can run this software. Which resonator? BTW, I responded to the same problem in CanadaCraigs thread. With so much sludge build up I would suspect heavy deposits on the intake valves. Same as part throttle operation.
  9. Craig, I have not read every post in this thread but most of yours. I understand many things have been checked and replaced or ruled out. I did not notice if your car is equiped with traction control. The Lexus traction control is a second butterfly or throttle plate. If it is partially closed it could be throttling your engine. Don't know if that has been inspected. Not certain if if could be open when the engine is off and then close up with it running due to an out of whack signal somewhere. Partially blocked exhaust will also throttle the engine. I would confirm that the catalysts are not damaged in any way. A cracked, melted or fouled monolyth core could cause your symptoms. Another possibility could be extreme buildup on your intake valves. I have seen some engines with massive deposits on the intake valves. Deposits will reduce the valve and ports flow ability and becomes a form of throttling. If an engine has enough deposits it would cause your symptoms. Hope this helps.
  10. I haven't reviewed your pre-purchase threads but reading between the lines I think the reason for you emotions is because you felt you HAD to buy it based on your research. The LS was not and so far is not the car of your emotional choice. Having owned a 96 LS400, driving it from 50k to 90k miles (40k total driving during ownership) there are MANY surprisingly GOOD things to discover about the car. One of my favorite was its 70mph punch. Perfect place in the gearing as it will drop to 2nd and scream to redline and then shift very nicely into 3rd. Try this against any of the cars you have mentioned and I think you will be surprised. Next was its surprising cornering ability. Find a clean 90 degree turn (one street turning onto another) and "test" how quickly you can make the turn. It will take some testing as you will discover it will get around it quicker than it seems possible. It will lean but it WILL turn. The LS400 is not designed as a sports car. That said another very nice thing to consider: If you have a sports car you are SUPPOSED to be quick/fast. The LS will stay with many so call sports cars in both acceleration and handling. Try it, you will be surprised. If you stay close the other car is shocked. You can't loose because you are in an LS for crying-out-loud. Also, girls may prefer sports cars but women prefer the LS. My suggestion, drive it, drive it hard, test the limits, you will gain a new respect and with it admiration. BTW, traded the 96 for a 99 which does almost everything better. Almost. The 96 idles better. The 99 does not have the 70mph punch due to gearing changes. The 99 has an 80mph punch. I think the 96 would out pull the 99 from a 70mph punch to probably 80mph before the 99 caught and passed the 96. The 95,96,97 are all basically the same as are the 98,99,2000 models.
  11. Yes they are now available. I have my set but have not installed them. Ironically, they are bolt in for the GS400, GS430, LS430 and SC430 but on my LS400 I must fabricate a new Y pipe. I had flanges cut and pipes ready but donated them to the first GS400 header install. I have just begun welding up a new Y pipe design called a "nozzle" collector based on what was learned on the GS above. Time restrictions dictate I will probably not install until spring. Dynos have been few so far. I have not personally dyno'd them. Results have been 15rwhp and up with a supercharged GS gaining 40rwhp at one point with an average of 25rwhp on the otherwise stock pipes. Here is the update thread. http://www.clublexus.com/forums/showthread.php?t=181544
  12. The S&S Headers are a direct bolt in and will not make the car louder but will add around 20rwhp.
  13. The BFI is an excellent suggestion. The most for the least. Best performance mod is probably the PI torque converter. It does not add power but will make dramatically better launches. Power wise I would suggest headers and a quality 2.25" dual exhaust copied after the Lexus dual Y pipe design. My nozzle collectors would be best IMO :whistles:
  14. I helped design the S&S Headers. They are a direct bolt in for the 1998-2000 GS400s and fit all the V8 engined cars. For the 92 SC400 you will need to modify move or replace the cats and build a custom Y pipe. They are not certified but are direct replacement parts for the GS400 and would not be a problem for most emission compliance situations.
  15. I am new to this board but not new to Lexus or internal combustion performance. A site member just joined another forum that I participate in and based on his comments I thought I would check out LOC. Good site from what I have read so far. Now, with regard to the performance potential of the Lexus exhaust system. I have seen a couple of posts here suggesting larger exhaust pipe size... DO NOT use larger than necessary exhaust pipe unless you want LESS low and mid RPM power. 2.50 pipe is TOO LARGE. Stock is 50mm (1.96") feeding a single 60mm (2.37") center pipe. I am currently working with a few members with both headers and either 2.00" or 2.25" pipes feeding a single 2.50 pipe before splitting back into duals. The Lexus dual Y pipe design is very effective for low RPM torque and is quiet. Another consideration is what year engine and what mods you plan in addition to exhaust. 1990-1994 LS400s and 1992-1995 SC400s are rated 250hp/260tq but IMO are actually over-rated and produce more like 230hp/240tq. 1995-1997 LS400s and 1996-1997 SC400s are rated 260hp/270tq and are fairly accurately rated. If anything the SCs are still a bit down on power due to the single tube exhaust manifold design vs. dual tube on the LS. The 1998-2000 GS400s are acurately rated 300hp/310tq. The 1998-2000 LS400s are accurately rated 290hp/300tq with a more restrictive cat back exhaust. The 1998-2000 SC400s are "slightly" overrated at 290hp/300tq again due to relatively poor exhaust manifold design. All models benefit from the S&S Headers especially the SC400s and early LS400s.
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