91greenbird

iTrader: (4)

well its time for my next mods and i think im gonna do intake i cant decide between hsr or modded tpi. hsr will lose alot of power down low but will gain alot from 4500rpms up but cost about $700 with everything u need to start it up and go but it requires some modifications to the fuel line and throttle body and heads. modded tpi consisting of tpis base, slp runners ported, and plenum ported and matched to slp runners will still have bad *** torque and will give me more then the 4500rpm wall tpi's have and is direct bolt on but cost about $1000. This car is my daily driver that will see the track once a month which should i chose. Im kinda leaning towards tpi because i seen dyno sheets and hsr makes your car lose alot of power until 4500rpms then u gain alot of power but whats the point on a stock internal 350 i would be afraid to take the iroc past redline which should i pick??

LT1FUN

Well, from the looks of it, this car sounds as if it's mainly for everyday street use with some occasional track time on weekends and such.

With that in mind, I'd suggest sticking with TPI. True, by the time you've upgraded the runners/intake (especially if you go to the high-end stuff like AS&M/TPIS) sticking with TPI will end up costing you more than a complete HSR set-up.

But you have to ask yourself, what's more important? Top end power (5500+) or low-mid range torque? On a daily driven street car, I'd choose low-mid range torque over top end HP any day of the week. Torque is what makes a car fun to drive.

You have to be realistic with what you plan on doing with the car. I mean, how often do you drive at 5500+rpm? Seriously. Probably not very often. So ditching TPI and loosing all that low-end torque, just to pick up some extra HP with the HSR kinda seems like a waste really, when you take into consideration that you'd only notice that HP advantage the HSR give you, in an RPM range that you're only in, what, 5-10% of the time anyways?

Not a good trade off in my opinion, but that's just me.

Like I said, it all depends on what you want from the car. If it's a serious street/strip car, and maximum performance is what you're looking for, go with the HSR, but for a fun street car to mess around in everyday, I'd stick with TPI.

Besides, TPI looks so much cooler

Personally, in the next few weeks, I'll be ordering AS&M big-tube runners and a TPIS big mouth intake base aswell as port the factory plenum. This set-up should pull all the way to 5500 and make enough torque to do a burn-out from here to the next town


Looking at your sig, it looks as if we have virtually the same mods done to our L98's.

I just installed SLP headers last week.

https://www.thirdgen.org/forums/exha...p-1-3-4-a.html

I have a 3" high flow cat, Dynomax cat-back, upgraded ignition and cut-out air baffles with K&N filters. 160 thermostat and coolant TB bypass. New Yokohama's all around, and I also advanced the timing. So basically, you and I have virtually the exact same mods. Same cars too though mine's an '88.

My goal with this car is just to run 12's with bolt-ons and just have a nice, clean, fun, daily driver. I have no use for an HSR...

Street Lethal

iTrader: (16)

How about the combination of both...

LT1FUN

Well, when you find an intake for the L98 capable of both, you let me know, 'cause it sure as hell isn't the HSR!

I know guy's who've done the swap, and have had the oppertunity to drive their cars on several occasions. The loss in low end compared to TPI is easily felt when you lay into it from a stand-still.

The loss of low-end is more than obvious....

Come on now, you're not saying that a HSR puts out the same torque numbers down low as TPI are you? There are countless comparisons out there that clearly show that while intakes like the HSR and miniram and such, have an advantage in the upper RPM's, when it comes to low-mid range torque, TPI is still king.

shaggy56

From everything I have seen the Superram seems to do this the best. At $1000 for the whole setup its a bit pricey though.

Street Lethal

iTrader: (16)

It's not finding an intake that is the problem here, it's everything else in a whole. So long as you obtain a decent flowing intake manifold, the entire power curve lies strictly within the valvetrain. Dynamic compression levels, aggressive lobes, duration, lift, LSA, air flow, all play key roles in obtaining power throughout the entire RPM band.

Yes, but that very same torque curve is easily re-attained by selecting the proper valvetrain components to complement the Holley Stealth Ram. Swapping to a 224/228 cam, with LSK lobes, and a 110+0 LSA will easily put that power back under the curve where you want it (while providing excellent upper-end performance, performance in which the stock L98 intake falls short of).

shaggy56

Yes what you say is true but he is speaking stock L98. So he has to deal with the poor flowing l98 heads which wont let anything like the HSR even flow near its proper potential.

Street Lethal

iTrader: (16)

But this is part of my point though. Never discredit a product when the condition in which it's performing is completely flawed. He asked if there was a manifold capeable of power both high and low, and the answer to his question is absolutely. I myself am running a FAST 90/90 setup on my LS1, and because of the grind of the cam that I chose, I have absolutely no loss in the lower end torque band, and she pulls extremely hard way above 6k....

Symmetry is the key here, everything must work in harmony. If the stock L98 heads and cam are flawed, they why would someone even consider throwing a HSR on top of it? It would only move the powerband upward, and being that the stock L98 is a complete dog at higher RPM's, you're doing more harm than good. But this doesn't mean that the HSR will not allow for low end torque, on the contrary, with the right setup, it'll provide more than one can imagine...

shaggy56

Well I cant speak for either because I never had the HSR and I cant even justify an LTR tpi anymore.

3rdgenZ

iTrader: (1)

all that is fine and dandy, but like the guy said it will be a daily driver
so in my own keep the tpi.maybe even a cam, then you can take advantage of the rpm youve gained.
or you could go with the hsr a take the money you saved and put a cam in it

Brisk

iTrader: (25)

well I'm going with the tpi route.. my car will see the track once or twice - ever. weekend warrior, not daily driver.. so the fun factor is priority #1 on my list... hell the cam I just installed made an obvious loss in torque.. something I wasn't too pleased about.

Street Lethal

iTrader: (16)

I don't understand the point here. A cam with a 110+0-LSA, 22x/22x duration, on an LSK lobe, is ideal for a daily driven 350 engine, and will provide ample power under the curve where its needed...

What are the cam spec's?

87TPI350KID

I would only go the HSR on a mild engine IF you have a stick. Feels like a 6 cyl off the line but pulls like a **** up top. I would just live with tpi's horrible 1/4 mph and bodacious 60' times

LT1FUN

As I said in my earlier posts, if you're looking for all out performance, go with the HSR. It'll make more HP than any TPI combination from 5500+. But since the starter of this thread is saying this is mainly a street car that will see track time maybe once a month, it appears (to me anyways) that having the fastest thing on the road isn't his number one priority.

So arguing about how you can get all your low-end torque back with HSR by going with a bigger cam with a 110 LSA seperation heads, gears, torque converter, proper tuning etc. etc. etc.... is irrelavant in this situation.

In order to take advantage the HSR's breathing capabilities, you'd have to upgrade to atleast 195cc heads (someting like the AFR's that have an opperating range that goes to 6500) and get a much bigger cam which will no doubt require custom tuning to get the car running properly. Good luck trying to find someone who can tune a car with a cam that has 110 LSA by the way

Also, he'd have no choice but to pick up a converter with a much higher stall speed and lower gears to go along with that kind of cam which would cause streetability problems not to mention his fuel consumption would go throught the roof. (I know what your saying, who cares abbout fuel consumption right? Well, people who use their cars as every day drivers do. Not eveyone is willing to spend $100/week on gas)

And after all is said and done, I'm absolutely positive a TPI set-up will still make MUCH more torque down low.

Their's a dyno less than 5 minutes from my house and I spend most of my summers hanging around there watching all the cars.

I've lost track how many HSR 3rd gen's I've seen dyno, and I have yet to see torque numbers that have impressed me in the slightest. They pull great up top, for sure, more than TPI ever could, but they cannot compete with the TPI's low-end grunt, no matter what cam I've seen them use.

Sorry, but we're going to have to agree to disagree on this one.

I'n his application, I'd still suggest sticking with TPI.

No use in having to upgrade every other part on the car, just to regain the low-end he lost by going with an HSR.

Can you get TPI-like torque out of an HSR? (I'll just have to take your word for it as I've personally never seen it happen - EVER!)

Is it worth all the extra hastle on a daily driver? Not in my eyes.....


Oh, and for the record, TPI is also capable of some truly discusting ET's if the builder knows what he's doing. Isn't there a 305 TPI running 9's in the 1/4 with the factory runners/base (ported of coars) running an ATI procharger somewhere on this board? I remember seeing the video once.

A couple local guy's are also running mid-low elevens with spraying their TPI's so it's not as if TPI's a total waste

Chrome

Jesus, by that logic and his "situation" why not just keep the factory TPI setup and save the money until he can justify a "higher performance" vehicle.

Dropping 1k for "upgraded" TPI components which really aren't going to net you that much especially if he really wants to get serious in the future is a waste of money; IMO.

Here's my suggestion. Don't do anything.

Save your money until you can get a decent set of heads (and they don't have to be AFRs). Get you a nice cam (228ish is NOT BIG) so you'll still have a decent idle. Pick up that Holley Stealth Ram. Also, you could invest in steeper gears (3.73) in the rear and a M6 (2nd overdrive). To take full advantage of your engine I would suggest stroking it to a 383 and you'll get your torque back... .

If you want to play; you have to pay... or something like that.

Kat

iTrader: (4)

I went from having a 6 speed/TPI combo pulling 2.1 60's and 13.7xx@101 mph to a 700/HSR pulling 1.8 60's and 13.601@100 mph (still the same tune as the stick/tpi setup)

:shrugh: The HSR isn't bad as people make it out to be. Yeah you do lose some torque, but you do make it up in the big end.

3rdgenZ

iTrader: (1)

[quote=Street Lethal]I don't understand the point here. A cam with a 110+0-LSA, 22x/22x duration, on an LSK lobe, is ideal for a daily driven 350 engine, and will provide ample power under the curve where its needed...

thats on a Ls1 right.
my point is that the tpi does all its work under 6k. the huge torque and med rang power is perfect for a street car.ls1 motors work completly dif, due to there port and intake design which is way better than a stock tpi.

Street Lethal

iTrader: (16)

To be quite honest here, the stock tuned port injection system does the majority of it's work under 4500-RPM. As for the LS1 being different, absolutely. However, a 350 cubic inch engine, is a 350 cubic inch engine (I know, the LS1 is a little smaller). I personally don't go by factory intake and head designs. Yes, the LS1 is much better in design from the factory... but the L98 can easily be made to match it in power. AFR heads, custom TR-cam, HSR intake, and the know how in tuning, and you can put down just as much as any LS1.

87TPI350KID

Loosing .32 seconds in my 60' time is not worth .1 in the 1/4.
With tpi, you can cruise along at 30 mph, pull it into 2nd and stand on it and watch the tires beg for mercy. With a stealthram, you can pull in into 2nd and it wont do much.. then all the sudden it pulls after the tpi rev band falls off. All you doing is pushing your peak hp and curve 1500 rpm up. And if you rev your car to 6500 rpm every day, then so be it.

Street Lethal

iTrader: (16)

It's in no way irrelevant. The Holley Stealth Ram is a superior piece to the "stock" TPI unit. Compression is obviously not reduced when switching to a better breathing intake system.... the torque that it produces though rises higher in the RPM band.

As for his situation, exactly what kind of situation is he in? I was in a similar situation when I installed my FAST 90/90 setup w/the stock LS1 camshaft. A little low end torque was lost (well, moved), but it came back ten fold with the installation of my current camshaft, in which, obviously, was designed to compliment it.

This comment pretty much summed it all up. You obviously know very little about cam overlap, and the affect that it has on an engine's idle....

Orr89RocZ

iTrader: (20)

nothing wrong with the HSR. if you bolt it on with stock tune it will run, but its not gonna make the power its capable of. the tune for TPI will make the HSR lean up topend and throw off air/fuel across the rev range.

a properly tuned HSR on a L98 should run alot better than the TPI. loss of low end will be minimal. gearing and converter in a 700r4 will give you all the low end you need. 3.06 first gear and 2800-3000stall is all you need with 3.27/3.42 gear out back. thats a powerfull lowend.

and the topend will be superior from 4000 on up to 5500. stock L98 cam will make power to 5grand. thats alot of improvement on past the 1/8 mile and timeslips will show atleast 1-2 tenths improvement.

case in point, my friends slp runner/bigmouth intake L98 runs pretty much dead even with me thru the 1/8 mile if I get a slight launch on him. else he's ahead by 1/2 car or so. but after that, his modded TPI makes better topend and he pulls away well. HSR would pull on me even harder. you can clearly see the topend advantage in this situation.

3rdgenZ

iTrader: (1)

so the real question is if he is willing to change his cam as well, and tune

Street Lethal

iTrader: (16)

Absolutely. I'd be the first to admit that throwing the Holley Stealth Ram on a stock L98 would be a big mistake, but if he's willing to compliment the HSR with better flowing heads, custom cam and tune, he'll make more power under the curve than any "stock" TPI system can produce, and then some....

1989GTATransAm

iTrader: (3)

The original poster was talking moded TPI. I have mine highly moded but don't expect it to match a HSR. An ASR probably.

I also agree with the posters on putting a HSR on an otherwise stock motor is a waste of money. You need to have the right combination of parts. Thats heads, cam, compression etc.

Orr89RocZ

iTrader: (20)

i kinda disagree.... the Ls1 features different heads/intake/exhaust ports all together. i believe they are 18 degree heads. it flows far superior to conventional 23 degree small block heads. it would take a very serious 23 degree head to match the same cc intake port LS1 head. LS1 ignition system too helps make power. Lsx design is just superior overall.

i dont know a whole lot of 400-450rwhp small block fuel injected 350's that can run like a 400-450rwhp Ls1. the reliability/driveability and mileage isnt there.

Kat

iTrader: (4)

I also went from a stick to a auto too. That helped a lot in the traction department.

If you are in to spinning tires, good for you from second gear. I kinda like how my just hooks and goes now. The HSR kinda matches the LT1 cam and LT4 rockers that are in the L98. Well the cam will be going soon, real soon for a XR282.

Street Lethal

iTrader: (16)

The reliability/driveability and mileage factor doesn't really have much to do with the design of the LS1 block and heads though. All engine's share the same thing in common, they pump air. The reason why the LSx family of engine's "feels" better, is mainly due to their more precise engine management systems, and more advanced ignition systems (individual coils per cylinder)...

contact

at some rpm, say 3000,
how much extra torque, do the
tuned pipes of TPI provide...

compared to 'nothing', ie
have the cyl-heads suck air directly from a plenum.?

I am aware that the 'ram-tuning' effect is real,
but is it as large as ten percent?

Shagwell

Kat's all over this one. - Dans87GTA is running an HSR. Mildly ported L98 heads(bowl job), 202/214, 497/502 112 cam. He lost ZERO 60ft and ZERO 330 switching from a ported TPI intake to the HSR, gained 5 mph and .09, and has actually had more traction issues now than before(thus the only .09 faster). He's spinning out of the hole and getting the same 60ft(= more power).....car still knocks down around 16mpg town, 21-22 highway, and he drives hard.
-otherwise, look into the FIRST intake system. - You couldn't give me a PITAram...er superam.

Orr89RocZ

iTrader: (20)

yep thats what i was goin for.. just didnt come out right

91greenbird

iTrader: (4)

im gonna stick with tpi since it is my daily driver and no were here tune and i dont have the money for 195cc heads or a cam at the time. I figured intake mods then cylinder heads (thinking of vette ported 113 heads) and a comp computer friendly cam with .474 lift on both sides 111 lsa and 220 intake and 224 exhaust duration which peak rpm for that cam is 5500rpms. With that in mind im gonna get a tpis bigmouth intake, slp runners (port them to match plenum), and a ported plenum and hope it pulls to 5500rpms. I agree with lt1guy completely hsr will be useless for me id be afraid to rev my stock internal 350 past 5500rpms and i like having low end and it cost to much to get all the parts to get your low end back. I would like some 3.27 or 3.45 gears but thats gonna be a pain in the *** because i have a the ****ty rare 9 bolt 2.77 rear.

JB97C5

The Superam is rather troublesome though. Ask other guys on the board.

I'd shop ebay and then port the lower intake (TPOS, Edeljob, etc ), SLP runners, and plenum as much as humanly possible. Save yourself some money and port it yourself.

shaggy56

I have the Superram so who do i need to ask. I just want to say that is the weakest excuse for people not to want the Superram