turbogrill Posted December 30, 2021 Report Share Posted December 30, 2021 Hi, I am not building a car but curious, how would you spend the points for a C4. This would be the L98 with the TPI option 1. 450 base 40 coilovers 10 camberoption2. 450 base 25 headers 25 intakeoption3 (auto). 375 base 50 cam 25 headers 25 intake 25 tb? It seems like a 0pts TPI could do around 220whp on a good day? Quote Link to comment Share on other sites More sharing options...
Team Infiniti Posted December 30, 2021 Report Share Posted December 30, 2021 2 hours ago, turbogrill said: Hi, I am not building a car but curious, how would you spend the points for a C4. This would be the L98 with the TPI option 1. 450 base 40 coilovers 10 camberoption2. 450 base 25 headers 25 intakeoption3 (auto). 375 base 50 cam 25 headers 25 intake 25 tb? It seems like a 0pts TPI could do around 220whp on a good day? Stock TBI intake is great for low down torque, match the cam and gear, it’s what the Stranger Ranger has been up to… 1 Quote Link to comment Share on other sites More sharing options...
Indysupra Posted December 30, 2021 Report Share Posted December 30, 2021 Oil pan 20 smog delete 5 splitter 10 wing 10 Quote Link to comment Share on other sites More sharing options...
jpm71 Posted December 30, 2021 Report Share Posted December 30, 2021 Jim with Subliminal Racing C4 team here. Eric (Indysupra) beat me to it above. If you plan to run decent tires and take advantage of the available tire widths, oil pan is a must - 20 points for 2021. Many stock spring and swaybar combinations available, so we worked that route and finally found something we like. That allowed us to do a splitter and wing for 10 each. We have a 5 point pulley for smog delete stuff. Tried accusump for 10 points, didn't get the job done. We have AIM with oil pressure light set and can still flip the warning light on occasionally, which is set at 18psi. Hope to reverse engineer an oil pan for just material points someday - might be a pipe dream. 4 Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted January 2, 2022 Report Share Posted January 2, 2022 I'd think the suspension on a C4 would be fine as is, as long as you use good factory NEW stuff. FWIW there are a host of MOOG springs that count as "stock" and Bilstein shocks are free in this league. I'd cut some weight, free. I'd also upgrade to C5/6 brakes. spoiler and splitter I'd do. The manifold is the killer on that engine. If the auto is a 700r4 it will seem like you are always in the wrong gear. I'd spend 20 on the oil pan for sure.... Quote Link to comment Share on other sites More sharing options...
Indysupra Posted January 2, 2022 Report Share Posted January 2, 2022 54 minutes ago, TiredBirds said: I'd think the suspension on a C4 would be fine as is, as long as you use good factory NEW stuff. FWIW there are a host of MOOG springs that count as "stock" and Bilstein shocks are free in this league. I'd cut some weight, free. I'd also upgrade to C5/6 brakes. spoiler and splitter I'd do. The manifold is the killer on that engine. If the auto is a 700r4 it will seem like you are always in the wrong gear. I'd spend 20 on the oil pan for sure.... There are zero aftermarket front springs for a c4 that count as stock at this point. We are going to be testing some vansteal springs once they get them done but we have been waiting awhile. with the stiffest front setup it’s still undersprung in the front. It’s fast but causes some other issues. Brakes have been a challenge for us. As we develop the car we get faster and harder on brakes. We have been killing front Wilwood rotors and have been plagued with uneven pad wear. The stock c5 stuff was ok at first but the pedal was garbage by the end of the first day. We are currently looking into other options for 22. We use the intake to our advantage. We have posted alot of AIM videos because we had people asking what we revved to. When I said 4200 they were in disbelief. Some tracks we will run out 4th but that is just to save a gear change. The low revving approach saves fuel and parts. 2 Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted January 2, 2022 Report Share Posted January 2, 2022 3 hours ago, Indysupra said: There are zero aftermarket front springs for a c4 that count as stock at this point. We are going to be testing some vansteal springs once they get them done but we have been waiting awhile. with the stiffest front setup it’s still undersprung in the front. It’s fast but causes some other issues. Brakes have been a challenge for us. As we develop the car we get faster and harder on brakes. We have been killing front Wilwood rotors and have been plagued with uneven pad wear. The stock c5 stuff was ok at first but the pedal was garbage by the end of the first day. We are currently looking into other options for 22. We use the intake to our advantage. We have posted alot of AIM videos because we had people asking what we revved to. When I said 4200 they were in disbelief. Some tracks we will run out 4th but that is just to save a gear change. The low revving approach saves fuel and parts. We run a Gen III f-body. We use a kit from bigbrakeupgrade.com. It is great, zero issues. It uses a C5/6 set up. We can carry tons of speed into the 1st turn. We use Napa rotors, zero isses. Moog has a bazillion different springs to choose from. Yes on shifting low...we run a 305 and shift around 5800, but it is not stock. Old car....new car is the same just black. Be nice to see some America iron at the track. https://www.youtube.com/watch?v=GpZHzZYXhJQ Quote Link to comment Share on other sites More sharing options...
atxe30 Posted January 2, 2022 Report Share Posted January 2, 2022 <poop-stir>love to know how a C4 is 450, a boxster is 475....#justsayin</poop-stir> 2 Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted January 2, 2022 Report Share Posted January 2, 2022 55 minutes ago, atxe30 said: <poop-stir>love to know how a C4 is 450, a boxster is 475....#justsayin</poop-stir> because a boxster is an expensive foreign sports car? 1 Quote Link to comment Share on other sites More sharing options...
jim161c Posted January 2, 2022 Report Share Posted January 2, 2022 The Boxster based on pure power to weight should be a 500 pt car. A BMW e30 which weighs 32lbs more and is a 10 year older platform if swapped to the same 201 HP as the Boxster would be a 506 point car........ 5 Quote Link to comment Share on other sites More sharing options...
Cam Benty Posted January 2, 2022 Report Share Posted January 2, 2022 1. Oiling system must be addressed. 2. Weight. 3. SBC 4. 90’S GM wiring issues. 5. Virtually nil camber and caster adjustments without points accumulation. IMHO. I am getting a lesson with my build. The spring issue needs clarification on what we can use as replacement. GM does not make replacement springs for the C4. At least I have not had any luck with it. I have received a lot of good advice from fellow racers. I will be asking for Moore in the future. 1 hour ago, atxe30 said: <poop-stir>love to know how a C4 is 450, a boxster is 475....#justsayin</poop-stir> Quote Link to comment Share on other sites More sharing options...
enginerd Posted January 3, 2022 Report Share Posted January 3, 2022 40 minutes ago, jim161c said: The Boxster based on pure power to weight should be a 500 pt car. A BMW e30 which weighs 32lbs more and is a 10 year older platform if swapped to the same 201 HP as the Boxster would be a 506 point car........ And the e30 has worse suspension design And has the aerodynamics of a brick 3 Quote Link to comment Share on other sites More sharing options...
hotchkis23 Posted January 3, 2022 Report Share Posted January 3, 2022 12 minutes ago, enginerd said: And the e30 has worse suspension design And has the aerodynamics of a brick From the guy that may have best overall finishing % driving said brick..... 1 Quote Link to comment Share on other sites More sharing options...
enginerd Posted January 3, 2022 Report Share Posted January 3, 2022 1 hour ago, hotchkis23 said: From the guy that may have best overall finishing % driving said brick..... Just think of how we would do in a boxster 4 1 Quote Link to comment Share on other sites More sharing options...
turbogrill Posted January 3, 2022 Author Report Share Posted January 3, 2022 thanks! Some great points Quote Link to comment Share on other sites More sharing options...
smitham32803 Posted January 3, 2022 Report Share Posted January 3, 2022 Having raced our C4 for several years the very first thing needs to be reliability. To keep the motor alive there are 3 key elements; keep RMP low SBC will not live all day at 6,000 RPM, good oil control (we have both an Accusump along with Road Race Pan), and keep it cool (we have an inexpensive Alum radiator). With reliability in mind you need to examine the choice for transmission. For the suspension we run the factory 86 Z51 springs along with new (new at the time we built the car) Bilstein shocks and C5 brakes. 2 Quote Link to comment Share on other sites More sharing options...
turbogrill Posted January 3, 2022 Author Report Share Posted January 3, 2022 (edited) What a out switching to a auto to free up 75pts? That could be used for cam+intake. Given the large displacement it should be possible to make lots of power at 5000 rpm? Or is it better to stick with manual. Edit:https://www.corvetteforum.com/forums/c4-tech-performance/3864228-my-recipe-for-300-whp-from-an-l98.html#post1600999381 This guy makes 300whp at 4000rpm and 350whp at 5000rpm, ridiculous! (cams+intake+headers) Edited January 3, 2022 by turbogrill Quote Link to comment Share on other sites More sharing options...
Indysupra Posted January 4, 2022 Report Share Posted January 4, 2022 It does not need more power. It would need fuel every hour at that point. Lol 1 Quote Link to comment Share on other sites More sharing options...
Bandit Posted January 4, 2022 Report Share Posted January 4, 2022 (edited) 20 hours ago, smitham32803 said: For the suspension we run the factory 86 Z51 springs Going from memory weren't the '84 Z51 springs the highest rate? There were Corvette Challenge springs but supposedly very difficult to find. I recall riding in a new one, '84 Z51, and feeling every pebble in the road. Edited January 4, 2022 by Bandit Quote Link to comment Share on other sites More sharing options...
smitham32803 Posted January 4, 2022 Report Share Posted January 4, 2022 4 hours ago, Bandit said: Going from memory weren't the '84 Z51 springs the highest rate? There were Corvette Challenge springs but supposedly very difficult to find. I recall riding in a new one, '84 Z51, and feeling every pebble in the road. They kept changing the spring rates each year with each model, so there are a lot of options. When building our car i researched it and found that 84 Z51 was the stiffest, and the 86 was like the 2nd or 3rd stiffest. As time went on they got softer, the later Z51's were even softer (i am sure they were catering to their crowd at the time ) 1 Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted January 4, 2022 Report Share Posted January 4, 2022 12 hours ago, Indysupra said: It does not need more power. It would need fuel every hour at that point. Lol our 305 uses 10gal/hour... so we get 1.5 hours out of the tiny tank booo Quote Link to comment Share on other sites More sharing options...
Bandit Posted January 5, 2022 Report Share Posted January 5, 2022 C4 springs for those wondering why you don't just change them or cut them. Options are limited. 1 2 Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted January 5, 2022 Report Share Posted January 5, 2022 9 hours ago, Bandit said: C4 springs for those wondering why you don't just change them or cut them. Options are limited. Could you go to a truck supply company and have some made? Quote Link to comment Share on other sites More sharing options...
smitham32803 Posted January 5, 2022 Report Share Posted January 5, 2022 No they are composite, and have a weird mount in the end of them. For a C4 you need to use C4 springs, C3 or C5 do not interchange and there are no longer any aftermarket springs available (when that was an option only one or two companies made them and they are out of business now). 1 Quote Link to comment Share on other sites More sharing options...
Team Infiniti Posted January 5, 2022 Report Share Posted January 5, 2022 24 minutes ago, smitham32803 said: No they are composite, and have a weird mount in the end of them. For a C4 you need to use C4 springs, C3 or C5 do not interchange and there are no longer any aftermarket springs available (when that was an option only one or two companies made them and they are out of business now). I have two 84 vett in the yard, one automatic (cut up to make a rat rod) the other is mostly complete personal barn find (bought almost 25 yrs ago and stuffed in storage to keep the other running) it's a 4+3, how can I determine if one of them has the stiff springs? Quote Link to comment Share on other sites More sharing options...
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