Guest bastaad525 Posted January 30, 2004 Share Posted January 30, 2004 SUs are a JOKE on Lseries motors that have modified heads. They simply can't flow enough CFMs... Mike heheh I say this half jokingly but: Norm get's away with them just fine funny I'm usually the anti-using-Norm-as-an-example guy because he is so much of an exception to the rule. But he does have the fastest running L6 in the 1/4 that I know of, and is running stock 240 SU's that he has modified himself, and running SM needles which can be gotten easily. He's also running a pretty mild cam. To me, when I saw a website showing all that he had done, the head stood out as the 'wow he has a lot of work in that' piece... the ports and chambers were all like mirror smooth. I believe he is running stock sized valves. SU's may not have the top end potential of trips but trips are a joke when it comes to street driving... at least, the only Z I've driven with trips was, and it was tuned on a dyno. Anyways... doesn't the saying go that "all the power in an L6 is found in the head"? I know when I was pondering buying a set of triples for my N/A most people advised against it as "I would not see much benefit from them on a stock head" Personally, I think the REAL way to go if you want carbs is to get a set of the 2" SU's that Rebello sells, and to get them to custom grind some needles for you. I've only read of a couple people that have used those but the few things I've read suggest they are GREAT for high performance L6's and a good middle ground between stock SU"s and trips, and wont give up your low end like trips seem to always do. Plus they aren't that much more expensive than a set of regular set of rebuilt SU's from MSA or Ztherapy. Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted January 30, 2004 Share Posted January 30, 2004 Well, I wouldn't call stock SU's a joke. Before I had the SU's bored out to just under 50 mm I ran them with the stock bore with the same engine setup and was pulling down 12.94 @ 104.49 mph on 24" drag radials. That mph definitely indicates the engine was putting out well in excess of 200 rwhp with stock bore SU's. When I switched to the big bore SU carbs I was initially only running 105.8 mph on 20" slicks. Later on I did a few minor mods and tranny regearing and upped the mph to 107.26 mph with 22" street tires this past fall and that's with spinning the tires in all 4 gears. People should STOP selling SU's short.They are great carbs!!! later,norm Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 30, 2004 Share Posted January 30, 2004 Well Doug Carrow's Z hauls serious ass with his trips and I think it all boils down to who is tuning them. No denying the work Norm has done to his beast... He has a combo that simply cannot be beat. But I know from personal and humiliating experience 1st hand... I nearly gave away a set of Mikunis that I could NOT get to run... The guy who bought them SPANKED me on a regular basis... He was GREAT at tuning them and keeping them sorted. EDIT: I was typing while Norm posted... Couple comments Norm, Your car hauls ass, but you are also on slicks, which does help a little... and Your SUs are big bore units that have been worked... They are the exception, not the dusty crusty normal example so many of the guys are stuck with! Mike Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 30, 2004 Share Posted January 30, 2004 Very few would use Mikunis if your results were the norm, Norm. I'm not aware of ANYONE who has come even close to your results with them. I like the idea of those carbs, but after switching to triples I would not go back. I have friends who autox and roadrace in Z's and 510's who feel the same way, and none who have gone to Mikunis and then decided to switch back to SU's. Jon Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted January 30, 2004 Share Posted January 30, 2004 EDIT: I was typing while Norm posted... Couple comments Norm' date=' Your car hauls ass, but you are also on slicks, which does help a little... and Your SUs are big bore units that have been worked... They are the exception, not the dusty crusty normal example so many of the guys are stuck with! Mike [/quote'] Hey remember Mike my 12.804 was done on regular $50 street tires. I haven't run slicks since November 2000. I "should" be down in the low 12.6's to high 12.5's with slicks now seeing as how badly I was spinning the street tires. later,norm Quote Link to comment Share on other sites More sharing options...
Guest FinalRights Posted January 30, 2004 Share Posted January 30, 2004 Lol,I haven't had much input in this topic in awhile. I've scrapped the entire idea of running anything extra on the 280. I've found out for sure that I can do the rb swap on my z31,so thats where all my money will be headed. The 280 is going to be the daily drive/if something breaks car. Quote Link to comment Share on other sites More sharing options...
Guest SpudZ Posted January 30, 2004 Share Posted January 30, 2004 Hey All, I have chatted with Doug Piner a bit over the last year or so , and his L24 in E Production trim... 12.5 to 1 compression , SU's and no larger then a .500 lift cam is making around 240 HP and over 200 ft lbs torque. He wouldn't send me a copy of his dyno sheet though ... He was concerned about all the money he spent on R & D for the engine If things go right this year . I might be building an L26 and using the 2000 pound weight limit that F Prepared autocross Z's are allowed with that engine displacement . Mike Quote Link to comment Share on other sites More sharing options...
zredbaron Posted January 30, 2004 Share Posted January 30, 2004 I think 200rwhp is attainable from a NA L-series without breaking the bank, doing a turbo conversion, or adding NOS... Flat top pistons N42/E31 big valve head - or some other combo in excess of 10:1 compression ratio Moderately hot cam Header/2.5" exhaust Triple 40's Electronic ignition Quality ignition system/multispark box Someone else with triples back me up here. I'm thinking more the other way around. Your standard port job probably nets 15 hp on a good day, while switching to Mikunis from stock SU's is EASILY worth 30 whp, properly tuned. I too have that exact setup, 3.1L stroker. Compression is too high for 93 octane. I just posted my dyno chart into my personal profile picture gallery. Sorry, I don't have a website for hosting pics. It is a very smooth graph, but the numbers are low. VERY low. 157 peak rwhp, 176 ft-lb max torque. (the gain between the runs was achieved solely by tuning the electromotive timing graph) Why is the power so low? I paid over $1k for what was supposedly a top notch head job. In return, I got back my E31 head cracked, littered with sand, and "assembled" (if you could call it that) with far too mild a cam. I had no window, I needed the car to run. It was assembled and has been crippled like this for 3 years now, but is rarely driven. Needless to say, I was pissed beyond my capacity. The car is still a blast to drive, beats most v8s, but the power isnt where it should be. So basically this just goes to show you that it only takes one weak link to ruin a potentially powerful engine. Especially head work. As many of you know, I am getting to redo my head and upgrade my 3x2 40mm dcoes to one of TWM's hex throttle body setups. Well, probably. I still haven't decided for sure. Regardless, I hope to get over 250rwhp when I rebuild. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 30, 2004 Share Posted January 30, 2004 I just realized that my 200 hp estimates for SU's is based on ITS motors which can't up compression and do port jobs. My bad. This added to the fact that Doug Piner (don't know him personally but it sounds like he has a lot of $$$ in the engine) can't get over 240hp with 12.5:1 compression and lots of headwork leads me to believe that the SU's are still a serious handicap in comparison to triples or TB's. Jon Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted January 30, 2004 Share Posted January 30, 2004 I just realized that my 200 hp estimates for SU's is based on ITS motors which can't up compression and do port jobs. My bad. This added to the fact that Doug Piner (don't know him personally but it sounds like he has a lot of $$$ in the engine) can't get over 240hp with 12.5:1 compression and lots of headwork leads me to believe that the SU's are still a serious handicap in comparison to triples or TB's. Jon Hey Jon, don't assume that the SU carbs are the limiting factor there.He is only running a 2.4L and so therefore he can only injest so much air into that small displacement engine. Later,norm Quote Link to comment Share on other sites More sharing options...
Mack Posted January 30, 2004 Share Posted January 30, 2004 yes, i would tend to agree with norm on this one. If he is indeed pushing 240hp out of an L24, I would think that would be about the limit for a SOHC, non crossflow 2.4L motor. unless your BRE/Pete Brock and your insane and have a way bigger budget than brains, then I guess 268hp is the limit on an L24. thats what it says in the little book that came with my model, lol! it lists 11.5:1 compression, 8200rpm redline and a bore of 3.660 in. I gues thats a .040" overbore. still a hell of a lot of HP. and tripple 44pph solex/mikuni carbs. I guess if you added 30 more cubic inches, who knows that the limit is if you had their head porting knowledge and expertise, not to mention budget. On a side note, Will i be the first to use the maxima N47 in a build up? I haven't seen anyone else on here with one.......... McAdam Quote Link to comment Share on other sites More sharing options...
Guest SpudZ Posted January 30, 2004 Share Posted January 30, 2004 Hey All, when I gave Dougs figure of 240 Hp for his L24 that was a rounded number he actually said over 240 HP , but wouldn't tell me the exact number . Remember that E Production Z motors are Limited Prep . I am not sure they are allowed to do a whole lot to the internals of the motor like a GT2 engine. If I remember right , Scott from Ztherapy quoted a 170 CFM flow for the Z SU's . An L24 is 146 cu. in . , L26 is 157 cu. in . , and a L28 is 168 cu in. . In my Auto Math book they did the flow calculations on a 350 cu. in. small block Chevy in Super Stock trim and came out with a 600 CFM carb for it . It ran faster with the 600 then the 650 CFM carb. I know there is many more factors here , cam, head flow and exhuast flow. If we take those numbers above in to consideration then Norms 2.9 liter would be close to the flow max of the stock bore SU's . Probably one reason why he bored his out for the added flow. I would figure a healthy race prepped L28 would need to tripples , but anything less then that would to fine with the SU's. Mike Haven't a clue what I am talking about Quote Link to comment Share on other sites More sharing options...
johnc Posted January 30, 2004 Share Posted January 30, 2004 FYI... Chet Whittle ran a Sunbelt 2.4L engine in ITS that made an honest 205 hp on basically stock SUs. There are a number of other ITS 2.4Ls running about the same power with stock internals and SUs. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 30, 2004 Share Posted January 30, 2004 OK, I'm giving up. SU's are GREAT. That's why all the people who aren't limited by class use nothing but SU's, right? You guys want to waste time and $$$ trying to draw blood from a stone with SU's, fine. As someone who has run the EXACT same motor with SU's and triples and had I would guess 40 hp gain from the triples (it was REALLY surprising), I am now and will forever remain unconvinced. And I wasn't a moron with the SU's either. Just for reference the SU manifold was port matched and the carbs were rebuilt and tuned well. I played around with oils and wound up using ATF and Marvel Mystery oil. I get tired of this persistant denial with SU's. The problem for me is that for YEARS the SU contingent had me totally fooled. I would run around telling OTHER people not to switch to Mikunis. Finally I broke down and switched after years of badgering by my 510 racing roommate plus I got the opportunity to buy the whole setup for $300, and he was right and I will not go back. Until you all try running the SAME engine with SU's and Mikunis you won't truly understand the difference. It is a BIG difference. Jon Quote Link to comment Share on other sites More sharing options...
Drax240z Posted January 30, 2004 Share Posted January 30, 2004 I'm with Jon on this one. Hows this, there is a 2.3L (4 cylinder) in a 510 around here that is running a custom cast manifold, and dual Z SU's. There is also the exact same buildup running dual 40 DCOE's. I mean exact, same pistons, same cam, same header, same freaking everything. (the young guy was impressed with the other setup, so he copied it to a T - except when it came to carbs) The SU car is very lively, does great at low speed/autocross, gets good economy and rips it up pretty much. A pretty easy car to drive fast. The Dual DCOE 40 car is half-ass tuned, and is comparible in acceleration to the SU car when going flat out. If this engine is tuned properly (which it is in line for at our shop) I have no reservations in saying it will pull on the SU car. Proof? Not really. But more fuel for the fire. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 30, 2004 Share Posted January 30, 2004 Come on, Drax! You gotta push him up in the line so you can prove our point!!! Except do me a favor and get that guy some 44's... Jon Quote Link to comment Share on other sites More sharing options...
Drax240z Posted January 30, 2004 Share Posted January 30, 2004 I can probably swing a race between the two, but it might be a few months. I'm going to but a G-TECH PRO soon so that might have to suffice. Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted January 30, 2004 Share Posted January 30, 2004 Sorta ditto what Jon said. There are people (Norm, Scott Bruning, Sunbelt) who can make killer hp with SUs. Then there's the rest of us. I too put off 3x2s to the very end (actually a good policy, imo, do the rest FIRST). They far exceeded my expectations. On the track, the Sunbelt headwork and cam was next to worthless without the triples. Prior to the head and cam, with 2" SUs and a Schneider grind I got 190 lb-ft and 180hp. After the headwork and prior to 3x2s, the engine still didn't want to pull hard up top at the track, and the midrange was now suffering. No good at all. Installed used triples (had been run on a 3.1 liter in Japan) Thursday, went to the dyno Friday and put down 235 to the wheels at 6500 rpm. At the track that Sat/Sun the car was fundamentally transformed above 5500rpm. WHEEEEEEEE! I would bet that the headwork without the carbs might've gotten me 10-15hp, and I'd bet the carbs without the headwork might've gotten me a 15-20hp. The two together, though, gave 55hp! Quote Link to comment Share on other sites More sharing options...
Guest norm[T12SDSUD] Posted January 30, 2004 Share Posted January 30, 2004 Hey Jon, I think you missed my point.I never once suggested that the SU's were superior to the triples. I was merely pointing out the fact that SU's can make some serious HP!! Loan me your Mikuni's for a month and I'll test the theory of triples superiority!! LOL Actually, with my mild cam, triples would not add much HP over the SU's.However, were I to go with a more radical cam I could see a large HP gain being possible. later,norm Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 30, 2004 Share Posted January 30, 2004 I know what you're saying Norm, and I appreciate the fact that you have made BIG hp with SU's. But people prop you up as an example and say that triples are a waste of time and $$$, and hell, I used to be one of them! I respect your accomplishments with them, but I've learned that Mikunis are faster. Oh, and get your own damn triples! Jon Quote Link to comment Share on other sites More sharing options...
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