How feasible is low 12s on the long tube TPI design? Obviously port/polish is ok as are things like the SLP runners/base etc. I'm just curious if low 12s is realistic on a 350 TPI car with this intake design. I've seen plenty in the 12s, and a couple in the low 12's but the ones I've seen in the low 12s were running minram or stealth ram setups. Not the TPI long tube design. As some of you have read I plan on jumping into a z28 with a TPI 5.0 with a 5 speed and will slowly turn it into a street machine I'll build a motor around a future 327 or 350 drop in. I was just wondering how well these long tube designs can be rigged up to flow.

 

My buddy had a 383 with ASM runners and a non-ported TPIS base, AFR 190s and 1.75" SLP shorties and ran a 12.25.

We won't get into what he could've run with another intake, but the long tubes can flow well enough to support 12s. Again, that's not to say another intake wouldn't have been better.

 

Right I know another intake could be better, I've looked around and I can't seem to find much on just getting intake systems. Everyone wants to sell injectors, fuel rails and all kinds of **** I would not need. Basically I'm just trying to get a feel for what the standard system is capable of, and if folks wanna comment on other intakes, list prices and links so I can read up. But 2500 bucks for an intake system is pretty ridiculous if you ask me.

 

Stealth Ram is 650 TOTAL, including the upper, lower and all the little things to finish the install.

 

Thats not bad, what are some of the other options?

Are these intakes necessary if you're only real goal is low 12's?


It would seem like switching to a stealth ram or something similar would give you a lot more options with respect to mods simply because you have a lot more breathing room to work with. Seems like those are good to 6500 rpm or so on a 350 or 383...but I'm still playing catchup after being out of the game for a few years so I could be wrong.

 

probably very true, i can pull to 5800 with ease with stock cam, heads, ect ect. i think its the best intake for the money. if you look at most comparisons the only one that beats it hp wise is the mini ram, and thats only by a few. then the torque numbers are still up there with the long tube designs.

 

I read an article last night that said the stealth ram flowed better than the mini ram up top? I guess it was wrong....

Seems like it may be worth the 650 dollars or so to throw one on the 305 until I build the 350.


Did you notice a big drop in low end torque?

 

Do a search for thirdgen member "Mike Crews". He is/was(been a year or two) a 383 LTR set-up w/ vortec heads. He was running 11.96 last I knew...not bad for a stock very appearing LTR car.

- The stealthram can be had cheap as just the intake and fuel rails. It's bang for you buck. - Deff. more adaptable/responsive.

later, justin...

 

Yah I would like to know the difference in how a stealth ram feels compared to a LTR setup. I am wondering when my stock intake will be come a hinderance, it probably already is. I have wondered about runnin a stealth ram on my 305.

 

Chevy HiPerformance magazine did a story last fall on just a """350"""" that ran 12's. This just had a bigger cam, tubes, manifold, and throttle body. It showed how easy it was to get there with proper parts.

 

I would imagined with your setup you'll see a good shift north in power delivery. Just based on what I'm reading on the web, it appears even on stock cars to have a moderate affect on 4000+ rpm performance. You've got some stuff done that may see a significant benefit from an intake change.

 

There is a guy on these boards who posts frequently and boasts a 12.XX time with a 355 LTR, trick Flow heads and a smaller cam. The cam is below 224.* He is N/A as well. The LTR design is not a horrible choice, just invest in a set of good heads and exhaust.

 

You can make fast vehicles, it looks as if low 12s is possible. Basically I'm debating if I'd build a motor smaller than a350 and stick with the LTR design or build a 350 with something like a stealthram setup. I'm not doing either in the near future I haven't even found the car yet but it makes for good discussion and has me wondering what I should do with reguards to future modification/engine selections. Seems like on a 305 its adaquate and even for some bigger applications. I personally like a lot of passing power in a vehicle, which the TPI LTR system has, but it runs out of steam above 5000+ at least thats what I gather from reading. Looks like SLP siamesed runners and a ported plenum and lower intake help a lot, but it still seems to pose a restriction.

 

I have a ported TPI ( Edlebrock HI flow base and runners) The runners . Now running with a ZZ4 ....the top end was at 4900 . So don't expect a big difference in the power band location . Just less of a drop off.

As far as TPI not makeing power above 5000 .....try above 4800 ...and that is a but less as the cubes shoot up .



Good luck man

 

TPI can pull off good et's with the mph they can trap. the mph will be somewhat lower than most other cars because of the less horsepower but the insane torque gets me running quick in the 1/8th and thus enables decent ET's but with low mph.

to me, low 12's isnt that quick anymore with alot of cars in the 11's nowadays and being very streetable. mid low 12's at 108-110mph is nice but those times will only come on very good launch with big street tires or a good launch with slicks/radials. on the street, you will get beat by turbo fwd cars that do 13.0s but they trap 115mph. and alot of other domestics like the ls1 and cobra stangs that do like mid 12s with bolt ons and trap 115mph. all the while their gettin great gas mileage to boot. so its best to ditch teh LTR, unless u dont mind not being able to go faster than mid 12's. i do

swap on another intake like miniram and stealth ram and pick up 50hp or more and run those same et's at 115mph on street tires.

that performance gain is just worth it. might as well get the most use out of those 1500 dollar heads. in smog legal places, well superram is the best bet. still flows more than any LTR. kinda a PITA and expensive but its your only legal alternative.

 

The stealth ram and mini ram seem to be good setups and give a lot more breathing room on the top end of things. For 650 bucks it seems liek it would be well worth the difference of only a couple hundred dollars from a ported TPI LTR setup.

 

yeah the cost of LTR setup is about 300 for the base used.. and 300 for runners used.

new, your looking at like 450 base, 450 runners if u dont use the SLP's... 250 for slps

so depending on where u shop, ur looking at anywhere from 500-900 dollars for a TPI LTR setup, not including the porting u might need to have done for 383 motors and higher revs on 350's.

600-650 dollars for a NEW stealth ram just blows TPI LTR out of the water

 

i did notice a drop, but not a big one. it picked up enough top end hp so that my ETs didnt differ any. i can tell you, that if i hang it in 1st gear and try to hit 30mph im at something like 4000rpm, as with the stock intake i was only at 3k.

 

mph and rpm shouldnt vary with intake swaps. gears from ur rear end and tranny affect that

intakes affect ur power levels so the time it takes to get to one speed will change

 

i did notice a drop, but not a big one. it picked up enough top end hp so that my ETs didnt differ any. i can tell you, that if i hang it in 1st gear and try to hit 30mph im at something like 4000rpm, as with the stock intake i was only at 3k.

 

Intake's do not affect your rpm and speed. Transmission and rear gearing does.

 

I've run a 12.86 @ 106 with my 383 TF Heads, LPE 219 cam, ASM Runners, and edelbrock intake. Small S-10 convter too on 3.27's. I know there is more since I had some wheel spin during those runs.

 

then explain how it changed without me messing with the tranny or rear end. a simple intake change, and it happened

 

It didn't, its that simple. Engine RPM and MPH are tied to transmission gearing, and rear differential gearing. Simply changing intakes or exhausts or both will not result in a change of RPM at a given speed. The changes can and do affect acceleration but an intake change can not effect your RPM at a given mph.

 

Thats an impressive time given your MPH. My car traps at 105mph and the best I've been able to pull is a 13.3 on street tires.

 

I plan on being in the low 12's with in 6 months. I'm having a new short block built up. My Total Seal rings are not sealing the oil al that well. So the new block will be .030 over, Comp Cams XFI268-113 cam, further cleanup and porting my Trick Flow heads.

I will also be installing Dyno Don's 1 3/4" headers and converting to speed density for max airflow on the intake side. I just had the 3 1/2" Mufflex sytem installed and the Meziere electric water pump. I think the lower 12's will be in the offering.

By the way this will be in a car with all the options including air condition and cruise contol on my trips to the track.

 

Bang for you buck...still stealthram. - Look into an intake called "FIRST" if you do a search on here you'll find abunch of info. It's a bit more dough, but it really makes a good happy medium between low rpm torque and high rpm hp. It's a lot like a LTR, but the runners are shorter(something like 2in shorter) and they mount closer to the center of the intake, thus shortening the runner length in the base also. It even has the prevision for an EGR, so it's emmissions legal.

later, justin...

- rpm vs mph is ONLY changed through gearing - not trying to flame, just agreeing with a fact.

 

Not only that, the FIRST system is HUGE in general. the runners and openings in the base are substantially bigger than aftermarket ported TPI's

 

Never even heard of it, who makes it? What kind price do they have on it?

 

i realize all of this, BUT as i said...if i put it in first (i have an auto) and i try to get to 30mph it wont get there until about 4000rpm. BEFORE the intake swap 30mph was 3000rpm DEAD ON everytime. i know this because alot of the stupid street racing that i do is from a 30mph roll

 

Dude its IMPOSSIBLE for an intake change alone to affect the RPM/MPH correlation. You changed something else or misread your tach. If you wanna know how/why this could happen start your own thread. It is NOT possible, I dont wanna clutter this up anymore with this RPM vs MPH stuff.

 

http://ncarboni.home.att.net/NCtpi.html

there's some info on a first TPI on a 418 roller motor.. went 12.85 at 111mph. not bad but no where near where i would expect a 418 to be... probly alot more in it left.. with better tunning and cam.. and with a stealth ram or miniram i would say mid bottom 11's if done right. 87 TA is high 10's at 126's with miniram 406


heres a quick comparison from a thread i read
RPM ---- ASM --- FIRST --- MR
2500 ---- 183 ----- 175 ----- 175
2750 ---- 215 ----- 200 ----- 200
3000 ---- 242 ----- 235 ----- 220
3250 ---- 268 ----- 265 ----- 240
3500 ---- 300 ----- 295 ----- 268
3750 ---- 318 ----- 328 ----- 283
4000 ---- 332 ----- 350 ----- 300
4250 ---- 350 ----- 367 ----- 325
4500 ---- 358 ----- 375 ----- 348
4750 ---- 360 ----- 382 ----- 363
5000 ---- 358 ----- 387 ----- 377
5250 ---- 350 ----- 374 ----- 387
5500 ---- 328 ----- 362 ----- 397


website i believe
www.firstinjections.com

 

The trick Flows canreally be opened up on the exhaust side. The exhaust is meant to fit the stock manifolds. If you have hooker long tubes, or even any header, you can really open the exhaust side up.

 

Man that miniram is impressive, it just kept right on building power. Although for street use the FIRST system looks to be good, it developes a lot more low and midrange power than the miniram and still provides a pretty good top end power curve.

As you said though those are pathetic numbers for a 400+ cu in built motor.

But man that miniram is badass up top

 

Not to add clutter, but he's correct. it is IMPOSSIBLE for an intake to make such a change. 100 HP or 1000HP, both would still reach the same MPH at the same RPM, assuming everything else stayed constant.

----------------------------------------

To stay on topic... ....I personally am a fan of the stock appearing long tube look. I've read a LOT on what can be done and still make power. It's also important to remember that street driving/butt dyno is a LOT different than comparing numbers on a quarter mile run. A TPI running mid 13s losing a 1/4 run to a mid 12 second LS1 is a huge loss. 1 second is FOREVER in the quarter. On the street, especially with all that low end, the two are almost even in most cases. Stoplight to stoplight, you'd never know the difference. Only at higher speeds or highway driving would the LS1 motor really start to break away. It depends what's important.

 

miniram is only great for large inch applications that need alot of air period, and/or super high reving motors, or a all out high end drag racing motor where u want most all topend

it can work on any motor.. but the lack of bottom end power might make the difference on the street compared to a TPI or FIRST

as u can see, miniram keeps pulling to 5500rpms and beyond. i'm not sure of the specs on the comparison, but minirams can support 7000rpms more than likely. many are very comfortable in the 6000+ range.

TPI is out by 5000rpms. for a street car, that aint bad if ur looking to make alot of power under the curve. TPI and FIRST have big edge over miniram at all rpm levels below 4500rpms. but after that.. miniram just makes numbers and stands out.

if u gear it right and keep the motor running that high, a TPI motor wont stand a chance against that miniram car. superior top end will win after the 1/8 mile everytime.

 

Yeah but that first system seems to do pretty good and getting into the 12's on a first system should be somewhat easy and I dont have to rev the motor to the moon. The first system runs out of breath on a 406 but on a 350 or 327 I bet you could squeeze 6k out of it without much problem and probably be fairly deep into the 12's on that intake and still have great power on the street.

 

thats what i think too.. the first system seems to pull good in the mid 5000's similar to a superram and should be a nice 12 second combo without too much effort.... the price i think its about the same for the two systems so its ur choice.

else try a extrude honed aftermarket system... should make good airflow but will be expensive, so buy your parts used

 

To clarify, the dyno numbers listed above were pulled from a May 1991 Popular Hot Rodding article entitled EFI Shootout

The engine used was a 9:1 355 with AFR Heads and a mystery “AFR cam”. However,,,, in order to get similar numbers using the EAPro simulation program with no more than a cam change,, it should be around a 214/224 - 112 with .440 / .465 lift. If that looks somewhat familiar,, that's probably why AFR didn't want to give the specs. Anyway,,, the ASM system is a fully ported GM base and ASM long tube runners. The "FIRST" unit was being sold by Electromotive in 1991 and the design has not changed. I believe the MiniRam may have had a revision or two since 1991, but I wouldn't expect to see any significant gains.

I've run the FIRST and the StealthRam on the 9.8:1 355 in my IROC. In my opinion the FIRST unit is better suited for my combination than the StealthRam,,,, due more to the car's 2800 stall and 3.23 gears than the engine. It's run a 12.59 at almost 108mph with the FIRST in 85degree weather shifting at 5800 / 5600 rpm. To get the StealthRam to run similar ETs I was shifting at 6400/6200 - which was a little high for my taste using a hydraulic flat tappet (218/228 -110) and stamped steel rocker arms. The midrange rush is great with the FIRST, something I missed when I had the StealthRam on the car. Still, the HSR is hard to beat if you're doing more racing than driving. It was impossible to screw up the launch at the track with the HSR even when the car had a totally stock suspension- heat the slicks and floor it. Either intake works about the same on my middle of the road combination, but the more you more to the right or left, would determine which intake would work best.

 

EA makes this EApro but where can I find a copy?


btw taht trap speed is impressive with the FIRST system. What kind of dyno numbers do you have?

 

Jegs has the standard version 759-EA32C for $117. It gets peak power numbers remarkably close, but the power curves show up smoother than the real deal. It doesn't show typical peaks and dips that you get when the wrong diameter or length headers are used,,, or say if the exhaust port opening is made too large - which happens a lot with back yard porting. The PRO version is down right amazing at how closely it matches the actual dyno curves. The EA Pro version at Jegs is 759-EAP12I3 - it's $467. In my opinion it is well worth the money. here's the link to it for details-
http://www.performancetrends.com/Eng...r_Pro_v3.3.htm
It's harder to use and might not be a bad idea to e-mail or call performance trends to see if you could get the stardard version first, get comfortable with it then upgrade to EA Pro later. They used to allow you to do this. It's only a few bucks more at their site than Jegs anyway.

The IROC dynoed 330 rwhp at 5850 with the StealthRam. With the mild pocket port on the heads,,, and based on the ETs it ran in 85 degree temps, it should be making around 320 rwhp at or around 5300 with the box stock FIRST. I'm considering doing a little gasket matching on the FIRST and taking it to the track once the temps are in the high 40s or low 50s. I'd expect it to run in the mid 12.20 range between 111 - 112mph then.

 

wow very impressive

Looks like the first setup may be good for a 327 TPI revving to about 6k You think that would be a reasonable setup?

 

Thats sounds like a really good combination. I like de-stroke motors. - The 3.250 stroke of the 327 makes for less bottom end than a comparable 350, but a system like the FIRST would fix that, plus it would keep the motor from running out of breath at high r's. BadSS has been playing w/ the FIRST system. I believe there are several people making good power to around 6200-6500 rpm with it. If I was going back to efi I would look into it for the motor I have now...my new 3.50 stroke, 4.155 bore 380ci er...probably the Stealthram because this motor will probably see close to 8k

 

It will depend on the heads, cam, and exhaust whether or not the FIRST on a 327 would shift at or around 6,000. Changing the stroke on my set up should drop peak power to about 310 rwhp and raise peak power to 5600 – which you would shift around 6000. However, less HP at a higher rpm ALWAYS results in lower ETs given the engine is the only change. In this example if the 350 runs 12.60@108, the 327 would run 12.88@106.2. To run the same ETs with the 327, I’d have to change from 3.23s to 4.11 gears and run 400 more rpm worth of stall.

Of course, using the same car/heads,, if I went with a single plane MPFI like Holley or Edelbrock offers and embraced the RPM capability of the 327, I could put out as much as 345 rwhp at 6400 rpm, shifting as high as 6800rpm. Now,,, I could run 12.60@110mph with the original stall with just a gear change to 3.73s. Bumping the stall 400 rpm and using 4.11 gears with the short runner single plane I could run as quickly as 12.45@111mph. Of course optimizing the cam for the different intake systems should result in even better than estimated ETs. So,,, it is all about what you want and how far your cash will let you take it.

Shagwell,,, if I were building a 380 / 3.5 stroke engine to run 8000 rpm, I'd go with a Dominator flanged Brodix HV intake converted to EFI and a 2000cfm T/B. Of course,,, I'd have to check e-bay for months hoping to pick either or both up for pennies on the dollar - if you know what I mean.

 

Thanks for the response, are you using that EApro system to get your power numbers?

327 has always appealed to me for its ability to rev and be a reliable motor. Reliability is important and the 327 seems to offer good capability, while being unique in 3rd gens and as mentioned earlier the short stroke motors are typically very reliable. I've read that I could rev a 327 to 7,000 rpm pretty easily if the bottom end is built right, but when revving that high you seem to run a substantially higher risk of breaking the motor. I think when I build I'll build with the ability to run at 7000 rpm but keep my power band so that it peaks around 5800 to 6000 rpm and redline being about 6500 rpm. Based on whats going on what you've said peak power at 6000 or so is possible with a First system and I should be able to develope enough power to get deep into the 12s.

 

A quick question...sorry for o/t
If you change the intake and exhaust system on an engine (modified for performance) thus allowing the engine to produce a greater percentage of power, how might this affect the Torque Converter and its slippage and subsequent effect on RPM?

 

I've searched all over for this EApro software and have found nothing on it. Anyone have a link?

edit: found the link posted above

 

could cause more slip, maybe a couple hundred rpm...MAYBE.
but if your trans and your convertor are good, above your stall, it shouldn't really change
-sorry to be off topic

- I agree on the single plain/mpfi set-up, I guess I just kinda like the looks of the stealthram(and the like). I don't think I'll be turning 8k, I figure more around 75-7700. I may never go back to efi. Through my current combo(in sig) this was my daily driver. It's now going to be about a 20k mile a year car(I like the idea of power tour...) I'm currently running the single plain/750 carb combo. My peak hp is around 6700, but I usually turn it around 7200 in low gear...just feels good

- also, I agree fully about the heads and cam make the motor/power band.

 

You've gotta have an intake to support the heads and cam. If you try to rev a factory TPI system to 7k you'll do yourself no good beyond 5500 the system just doesn't breath.

 

u can rev any motor to 7000 rpms if its built right... nothing magical about a 327 over 355 or 383 or what not. just the bottom end needs to be built/balanced for it.