strotter Posted November 17, 2001 Share Posted November 17, 2001 I think I understand some of the advantages of single-plane intake manifolds - improved power and efficiency at high RPM's, with a moderate improvement at mid-ranges, and a decline at lower speeds. This sounds great for a high-reving engine, such as my 327, especially in a small, light car such as a Z. Although I am partial to high revs, I'm concerned about streetability and economy. I'm not looking for all-out power with a lumpy idle or twitchy behavior around town - something I associate with single-planes, though I have little experience with them. If my goal is a touring machine with some punch if I'm in a hurry, would the single-plane fit the bill, or would I be better off with the more conventional dual-plane? BTW, I'm preparing the motor to use a TBI unit from an '89 Firebird, with all the associated sensors and electronics, with one of the adapter plates available from Holley and others, and a set of ported/polished .202 "Double-hump" heads (#3782461's). Any comments/concerns would be appreciated. Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted November 17, 2001 Share Posted November 17, 2001 Scott, If you are going to run injection then a lot of the problems assocatiated with single plane manifolds can be tuned out. You dont have to worry about low air flow not sending the right signal to the carb. The victor jr seem to be a favoured manifold, however i wonder if you can get away with something more like a tunnel ram becuase of the advantages of fuel injection. Any one else know? Douglas Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 17, 2001 Share Posted November 17, 2001 Hood clearance provided, a tunnel ram could easily be (and has been) used in a multiport system, the one I saw used a sheetmetal upper for the plenum with the throttlebody on the front. Not sure on they're performance, but I'm sure it can't be that bad. Regards, Lone Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted November 18, 2001 Share Posted November 18, 2001 I am running a 350 with dual TBI's on a tunnel ram now and it is fine so far. I have recently purchased a dual four low rise manifold that I will be swapping on now. I just have to work out some time from work to do so! Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted November 19, 2001 Share Posted November 19, 2001 Single plane sbc's rock in our light Z's IMO. I ran my V.Jr. 2975 with the performer carb and loved it...would shred from a 725rpm idle with no trouble. Idle was fine and I had no problems/issues with the single plane. I believe their conveyed poorly for the differences b/t them and dual planes....some guys run V.Jr's on trucks with milder cams and have no issues at all etc. They're not for 8k rpm race setups only by any means.....I just think if joe public new how streetable they were and they were so common on mild mills then a hardcore racer would feel he'd need something different which edelbrock would like to avoid...(like a super victor ) Your idle won't be the most fuel efficient but we're not comparing ourselves to Geo Metro's now so who cares I run the V.Jr. now with my EFI and am still loving it. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 19, 2001 Share Posted November 19, 2001 DrewZ, How does that work with twin tbi and how do you pull it off? What computer does it use. Kinda curious, I havn't seen that set up before outside of chevy's stock single TB version. Regards, Lone Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted November 19, 2001 Share Posted November 19, 2001 FWIW - Holley is going to be coming out with a Tunnel EFI intake soon. It was shown at SEMA this year but I've not yet seen pics Grump did Doug ever get pics to you? Going to have to get out to SEMA one of these days, sounds like a blast! I'm running a Vctor Jr myself and will be converting it to EFI. Low airflow at idle leads to wall wetting in a carb app supposedly but with EFI it's no biggie. I do see a fuel stain under my carb but it seems to run well off idle. Left a few feet of rubber just the oher day after shortshifting 2nd, these cars are light enough that they don't need massive low end torque.... Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 19, 2001 Share Posted November 19, 2001 I have the nice Holley Dual Plane (300-36) that's flows pretty good up top. As tested in the magazines against the Vic Jr. , it loses 10-15 hp above 6000 rpm for many warm (224@0.050") builds. My dilemna with my motor is that I'll gain top end HP (18 according to grumpyvette's computer) but DD2K show me giving up 25+ ft lbs at 2000, using the Vic Jr vs. the dual plane. It's still at something like 320 ft lbs with the Vic Jr (as opposed to 345ish with the dual plane). Sounds like plenty of fun, but what I'm concerned with is 70mph 5th gear cruise at 2100 rpm and throttle response. For people who've run similar cams (say 228/234@0.050" hyd. flat - mine's a 236/240@0.050" solid flat) to mine in a 9.7:1-ish 327 with the Vic Jr., can you comment on this situation (2100 rpm cruise throttle response)? Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 20, 2001 Share Posted November 20, 2001 BLKMGK no picture yet from DOUG. pparaska the difference between 345 ft lbs and 320 ft lbs is about 7.5% I doubt you will notice the difference in top gear at all but you will notice the loss of hp over the acceleration curve if you go with the dual plane intake Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted November 20, 2001 Share Posted November 20, 2001 Don't know if my cam compares Pete but my Vic pulls all the way down to about 1K or 1500 no problem - heck my car IDLES at 1K! No bucking as I ease into it in 6th when it's down low like that too. A shame you aren't closer by, I'd show ya'! Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 20, 2001 Share Posted November 20, 2001 BLKMGK, grumpyvette, thanks for the responses. I'm going for the Vic JR! Now if I only had more than 0.003" crank endplay, I could get this thing together! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 20, 2001 Share Posted November 20, 2001 I love the dual TBI idea. I have been trying to find a big block TBI for my SBC and have had no luck. With the 95+ computer they are fully prgramable and my buddy works in the shop for a GM dealer. Hell, maybe he can get me a smaoking deal on all new stuff!! Jake Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted November 21, 2001 Share Posted November 21, 2001 Hey lone wasuup man. Sorry about the slow response but the shop is still busy for anothe rmonth and than I will have no life except for the board like last winter!!! LMAO! It works really well with GREAT throttle response from idle I am using the .....787...or was it the 747.... can't remember exactly. It was a really easy system to make, I bought it mostly complete already, but its simplicity to dual TBI it was nothing at all. For example, if you had a 87 chev 1/2 ton with TBI all you need to do is get a dual manifold, second TBI with all connectors, and the hardest thing is to setup a base chip to work the duals from.The TBI's are not as voltage specific as TPI so the dual routing of the TBI wiring was not much of a difficult task. It helps that the guy I got the system from has been training GM tech's for 15 years, I believs??? Quote Link to comment Share on other sites More sharing options...
strotter Posted November 21, 2001 Author Share Posted November 21, 2001 OK, here's the deal, then: I'm gonna go for it, and see what I see. I've got a single-plane manifold already, a Holley Street Dominator (and I don't want to say how long it's been sitting in my closet). I mean, if it turns out to be a problem, I can afford the cost and effort to swap on another manifold. But man, I have to say, it looks just wicked cool. ZROSSA, you said I can "tune out" some of the problems associated with single-planes. I assume you mean by reprogramming the PROM. That begs two questions: first, what behaviors in particular are you talking about, and, second, how specifically would you do so? I'm a bit of a computer guy, and a bit of a car guy, but I've never in my life programmed a PROM - I imagine I'll be spending a lot of time in the apropriate forum at some later date, but I'd like to know it's something that can be done by a novice. I'm hoping that fuel injection will just *automatically* clean up some of those problems. Finally, I'd like to point out that I havn't picked out a cam yet, other than "steetable". I can say, however, that I'd like to stick with a factory hydraulic roller setup, much like that found on the 305 that's donating its' FI, electronics, and tranny. Perhaps one of the less radical cams, with 214 to 218 degrees duration (at .050" lift), with a wide lobe separation angle (112 to 114 degrees). Those numbers come from some of the Comp Cams, which I understand will yield streetable yet fun results. Any suggestions here would also be appreciated. Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted November 21, 2001 Share Posted November 21, 2001 Scott, I think the guys here have already covered most of it and for that matter are far better qualified than I to answer the question. The main thing with a single plane is lack of low rpm torque. This seems to be from lack of high speed airflow to properly mix the fuel and air together. Fuel injection doesnt need high manifold airflow to do this becuase its done with fuel pressure so it tends to pick up the low rpm torque. In saying all this a lot of the guys are runing big carbs and single plan manifolds and not having problems due to the low weight of the z. I hope this was some help and not misleading in any way, I am new to V8's and have always played with revy little fours in light cars in the past. Cheers Douglas Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted November 21, 2001 Share Posted November 21, 2001 I"m not familiar with the dominator single plane, look for a smooth transition as the runners square up to the intake ports......V.Jr. has this, Weiand Xcelerator does not have a smooth turn/quite angular. On a roller cam...LT1-4 OEM roller cams (yes used/cheap) are great with 1.6 rockers if your mill has higher compression. ZZ4 cam is a little larger and still has fine idle with 509/521 lift AIR with 1.5 rockers. Keep in mind you can run more attitude with a roller in comparison to non-roller and have same manners (ie. a roller will idle smoother with same spec'd lift vs. a non-roller). Lt1's/ZZ4 cams can be had for cheap from used mills and these cams were made from billet steel and are generally in as new shape. $50 is not an uncommon price Quote Link to comment Share on other sites More sharing options...
Guest chevsun Posted November 22, 2001 Share Posted November 22, 2001 Will the vic JR. fit under the stock hood? I have about 1/2" to spare with the RPM. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 22, 2001 Share Posted November 22, 2001 What about the Weiand Team G, anyone have any experience with that? Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted November 22, 2001 Share Posted November 22, 2001 I was runnin g a Scorpion with a 750 holley and it cleared so I believe most non-tunnelram intakes should clear with the low slung air filtre. The adjustment that I made to make my big cam work was to adjust the voltage valued at the map sensor. The base and range of voltage was adjusted until my motors powerband was steady. My cam is 290/292 500/509 with a 112sep. Quote Link to comment Share on other sites More sharing options...
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